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!14294 [翻译完成】#I6C6EJ 

Merge pull request !14294 from Annie_wang/PR14133
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en/application-dev/reference/apis/Readme-EN.md
浏览文件 @ 86bb6eb7
......@@ -215,9 +215,13 @@
- data/rdb
- [resultSet](js-apis-data-resultset.md)
- File Management
- [@ohos.environment (Environment)](js-apis-environment.md)
- [@ohos.file.environment (Directory Environment Capability)](js-apis-file-environment.md)
- [@ohos.file.fileAccess (User File Access and Management)](js-apis-fileAccess.md)
- [@ohos.file.fileExtensionInfo (User File Extension Information)](js-apis-fileExtensionInfo.md)
- [@ohos.file.fs (File Management)](js-apis-file-fs.md)
- [@ohos.file.hash (File Hash Processing)](js-apis-file-hash.md)
- [@ohos.file.securityLabel (Data Label)](js-apis-file-securityLabel.md)
- [@ohos.file.statvfs (File System Space Statistics)](js-apis-file-statvfs.md)
- [@ohos.filemanagement.userFileManager (User Data Management)](js-apis-userFileManager.md)
- [@ohos.multimedia.medialibrary (Media Library Management)](js-apis-medialibrary.md)
- [@ohos.storageStatistics (Application Storage Statistics)](js-apis-storage-statistics.md)
......
en/application-dev/reference/apis/js-apis-environment.md → en/application-dev/reference/apis/js-apis-file-environment.md
浏览文件 @ 86bb6eb7
# Environment
# @ohos.file.environment (Directory Environment Capability)
The **Environment** module provides APIs for obtaining the root directories of the storage and public files.
> **NOTE**
>
> - The initial APIs of this module are supported since API version 8. Newly added APIs will be marked with a superscript to indicate their earliest API version.
> - The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
> - The APIs of this module are system APIs and cannot be called by third-party applications.
> - The APIs of this module support processing of error codes. For details, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).
## Modules to Import
```js
import environment from '@ohos.environment';
import environment from '@ohos.file.environment';
```
## environment.getStorageDataDir
......@@ -30,10 +31,10 @@ Obtains the root directory of the storage. This API uses a promise to return the
**Example**
```js
environment.getStorageDataDir().then(function(path){
console.info("getStorageDataDir successfully:"+ path);
}).catch(function(error){
console.info("getStorageDataDir failed with error:"+ error);
environment.getStorageDataDir().then((path) => {
console.info("getStorageDataDir successfully, Path: " + path);
}).catch((err) => {
console.info("getStorageDataDir failed with error message: " + err.message + ", error code: " + err.code);
});
```
......@@ -54,8 +55,12 @@ Obtains the root directory of the storage. This API uses an asynchronous callbac
**Example**
```js
environment.getStorageDataDir(function(error, path){
// do something
environment.getStorageDataDir((err, path) => {
if (err) {
console.info("getStorageDataDir failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("getStorageDataDir successfully, Path: " + path);
}
});
```
......@@ -76,10 +81,10 @@ Obtains the root directory of public files. This API uses a promise to return th
**Example**
```js
environment.getUserDataDir().then(function(path){
console.info("getUserDataDir successfully:"+ path);
}).catch(function(error){
console.info("getUserDataDir failed with error:"+ error);
environment.getUserDataDir().then((path) => {
console.info("getUserDataDir successfully, Path: " + path);
}).catch((err) => {
console.info("getUserDataDir failed with error message: " + err.message + ", error code: " + err.code);
});
```
......@@ -100,7 +105,11 @@ Obtains the root directory of public files. This API uses an asynchronous callba
**Example**
```js
environment.getUserDataDir(function(error, path){
// do something
environment.getUserDataDir((err, path) => {
if (err) {
console.info("getUserDataDir failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("getUserDataDir successfully, Path: " + path);
}
});
```
en/application-dev/reference/apis/js-apis-file-fs.md 0 → 100644
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# @ohos.file.fs (File Management)
The **fs** module provides APIs for file operations, including basic file management, directory management, file information statistics, and stream read and write.
> **NOTE**
>
> - The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
> - The APIs of this module support processing of error codes. For details, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).
## Modules to Import
```js
import fs from '@ohos.file.fs';
```
## Guidelines
Before using the APIs provided by this module to perform operations on files or directories, obtain the path of the application sandbox as follows:
**Stage Model**
```js
import UIAbility from '@ohos.app.ability.UIAbility';
export default class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage) {
let context = this.context;
let pathDir = context.filesDir;
}
}
```
**FA Model**
```js
import featureAbility from '@ohos.ability.featureAbility';
let context = featureAbility.getContext();
context.getFilesDir().then((data) => {
let pathDir = data;
})
```
For details about how to obtain the FA model context, see [Context](js-apis-inner-app-context.md#context).
## fs.stat
stat(file: string|number): Promise<Stat>
Obtains detailed file information. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------------- |
| file | string\|number | Yes | Path of the file in the application sandbox or file descriptor (FD) of the file.|
**Return value**
| Type | Description |
| ---------------------------- | ---------- |
| Promise<[Stat](#stat)> | Promise used to return the file information obtained.|
**Example**
```js
let filePath = pathDir + "test.txt";
fs.stat(filePath).then((stat) => {
console.info("get file info succeed, the size of file is " + stat.size);
}).catch((err) => {
console.info("get file info failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.stat
stat(file: string|number, callback: AsyncCallback<Stat>): void
Obtains detailed file information. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ---------------------------------- | ---- | ------------------------------ |
| file | string\|number | Yes | Path of the file in the application sandbox or file descriptor (FD) of the file. |
| callback | AsyncCallback<[Stat](#stat)> | Yes | Callback invoked to return the file information obtained.|
**Example**
```js
fs.stat(pathDir, (err, stat) => {
if (err) {
console.info("get file info failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("get file info succeed, the size of file is " + stat.size);
}
});
```
## fs.statSync
statSync(file: string|number): Stat
Obtains detailed file information synchronously.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------------- |
| file | string\|number | Yes | Path of the file in the application sandbox or file descriptor (FD) of the file.|
**Return value**
| Type | Description |
| ------------- | ---------- |
| [Stat](#stat) | File information obtained.|
**Example**
```js
let stat = fs.statSync(pathDir);
console.info("get file info succeed, the size of file is " + stat.size);
```
## fs.access
access(path: string): Promise<boolean>
Checks whether a file exists. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the file in the application sandbox. |
**Return value**
| Type | Description |
| ------------------- | ---------------------------- |
| Promise<boolean> | Promise used to return a Boolean value. |
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.access(filePath).then((res) => {
if (res) {
console.info("file exists");
}
}).catch((err) => {
console.info("access failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.access
access(path: string, callback: AsyncCallback<boolean>): void
Checks whether a file exists. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------- | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the file in the application sandbox. |
| callback | AsyncCallback<boolean> | Yes | Callback invoked to return the result. |
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.access(filePath, (err, res) => {
if (err) {
console.info("access failed with error message: " + err.message + ", error code: " + err.code);
} else {
if (res) {
console.info("file exists");
}
}
});
```
## fs.accessSync
accessSync(path: string): boolean
Synchronously checks whether a file exists.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the file in the application sandbox. |
**Example**
```js
let filePath = pathDir + "/test.txt";
try {
let res = fs.accessSync(filePath);
if (res) {
console.info("file exists");
}
} catch(err) {
console.info("accessSync failed with error message: " + err.message + ", error code: " + err.code);
}
```
## fs.close
close(file: File|number): Promise<void>
Closes a file. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ---- | ------ | ---- | ------------ |
| file | [File](#file)\|number | Yes | File object or FD of the file to close.|
**Return value**
| Type | Description |
| ------------------- | ---------------------------- |
| Promise<void> | Promise that returns no value.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath);
fs.close(file).then(() => {
console.info("File closed");
fs.closeSync(file);
}).catch((err) => {
console.info("close file failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.close
close(file: File|number, callback: AsyncCallback<void>): void
Closes a file. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| -------- | ------------------------- | ---- | ------------ |
| file | [File](#file)\|number | Yes | File object or FD of the file to close.|
| callback | AsyncCallback<void> | Yes | Callback invoked when the file is closed asynchronously.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath);
fs.close(file, (err) => {
if (err) {
console.info("close file failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("close file success");
}
});
```
## fs.closeSync
closeSync(file: File|number): void
Synchronously closes a file.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ---- | ------ | ---- | ------------ |
| file | [File](#file)\|number | Yes | File object or FD of the file to close.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath);
fs.closeSync(file);
```
## fs.copyFile
copyFile(src: string|number, dest: string|number, mode?: number): Promise<void>
Copies a file. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ---- | -------------------------- | ---- | ---------------------------------------- |
| src | string\|number | Yes | Path or FD of the file to copy. |
| dest | string\|number | Yes | Destination path of the file or FD of the file created. |
| mode | number | No | Whether to overwrite the file of the same name in the destination path. The default value is **0**, which is the only value supported.<br>**0**: overwrite the file of the same name.|
**Return value**
| Type | Description |
| ------------------- | ---------------------------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
let srcPath = pathDir + "srcDir/test.txt";
let dstPath = pathDir + "dstDir/test.txt";
fs.copyFile(srcPath, dstPath).then(() => {
console.info("copy file succeed");
}).catch((err) => {
console.info("copy file failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.copyFile
copyFile(src: string|number, dest: string|number, mode?: number, callback: AsyncCallback&lt;void&gt;): void
Copies a file. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| -------- | -------------------------- | ---- | ---------------------------------------- |
| src | string\|number | Yes | Path or FD of the file to copy. |
| dest | string\|number | Yes | Destination path of the file or FD of the file created. |
| mode | number | No | Whether to overwrite the file of the same name in the destination path. The default value is **0**, which is the only value supported.<br>**0**: overwrite the file with the same name and truncate the part that is not overwritten.|
| callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked when the file is copied asynchronously. |
**Example**
```js
let srcPath = pathDir + "srcDir/test.txt";
let dstPath = pathDir + "dstDir/test.txt";
fs.copyFile(srcPath, dstPath, (err) => {
if (err) {
console.info("copy file failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("copy file success");
}
});
```
## fs.copyFileSync
copyFileSync(src: string|number, dest: string|number, mode?: number): void
Synchronously copies a file.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ---- | -------------------------- | ---- | ---------------------------------------- |
| src | string\|number | Yes | Path or FD of the file to copy. |
| dest | string\|number | Yes | Destination path of the file or FD of the file created. |
| mode | number | No | Whether to overwrite the file of the same name in the destination path. The default value is **0**, which is the only value supported.<br>**0**: overwrite the file with the same name and truncate the part that is not overwritten.|
**Example**
```js
let srcPath = pathDir + "srcDir/test.txt";
let dstPath = pathDir + "dstDir/test.txt";
fs.copyFileSync(srcPath, dstPath);
```
## fs.mkdir
mkdir(path: string): Promise&lt;void&gt;
Creates a directory. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the directory in the application sandbox. |
**Return value**
| Type | Description |
| ------------------- | ---------------------------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
let dirPath = pathDir + '/testDir';
fs.mkdir(dirPath).then(() => {
console.info("Directory created");
}).catch((err) => {
console.info("mkdir failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.mkdir
mkdir(path: string, callback: AsyncCallback&lt;void&gt;): void
Creates a directory. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------- | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the directory in the application sandbox. |
| callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked when the directory is created asynchronously. |
**Example**
```js
let dirPath = pathDir + '/testDir';
fs.mkdir(dirPath, (err) => {
if (err) {
console.info("mkdir failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("mkdir success");
}
});
```
## fs.mkdirSync
mkdirSync(path: string): void
Synchronously creates a directory.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the directory in the application sandbox. |
**Example**
```js
let dirPath = path + '/testDir';
fs.mkdirSync(dirPath);
```
## fs.open
open(path: string, mode?: number): Promise&lt;File&gt;
Opens a file. This API uses a promise to return the result. File uniform resource identifiers (URIs) are supported.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the file in the application sandbox or URI of the file. |
| mode | number | No | [Mode](#openmode) for opening the file. You must specify one of the following options. By default, the file is open in read-only mode.<br>- **OpenMode.READ_ONLY(0o0)**: Open the file in read-only mode.<br>- **OpenMode.WRITE_ONLY(0o1)**: Open the file in write-only mode.<br>- **OpenMode.READ_WRITE(0o2)**: Open the file in read/write mode.<br>You can also specify the following options, separated by a bitwise OR operator (|). By default, no additional options are given.<br>- **OpenMode.CREATE(0o100)**: If the file does not exist, create it.<br>- **OpenMode.TRUNC(0o1000)**: If the file exists and is open in write-only or read/write mode, truncate the file length to 0.<br>- **OpenMode.APPEND(0o2000)**: Open the file in append mode. New data will be added to the end of the file.<br>- **OpenMode.NONBLOCK(0o4000)**: If **path** points to a named pipe (also known as a FIFO), block special file, or character special file, perform non-blocking operations on the open file and in subsequent I/Os.<br>- **OpenMode.DIR(0o200000)**: If **path** does not point to a directory, throw an exception.<br>- **OpenMode.NOFOLLOW(0o400000)**: If **path** points to a symbolic link, throw an exception.<br>- **OpenMode.SYNC(0o4010000)**: Open the file in synchronous I/O mode.|
**Return value**
| Type | Description |
| --------------------- | ----------- |
| Promise&lt;[File](#file)&gt; | Promise used to return the file object.|
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.open(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE).then((file) => {
console.info("file fd: " + file.fd);
}).catch((err) => {
console.info("open file failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.open
open(path: string, mode?: number, callback: AsyncCallback&lt;File&gt;): void
Opens a file. This API uses an asynchronous callback to return the result. File URIs are supported.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------------- | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the file in the application sandbox or URI of the file. |
| mode | number | No | [Mode](#openmode) for opening the file. You must specify one of the following options. By default, the file is open in read-only mode.<br>- **OpenMode.READ_ONLY(0o0)**: Open the file in read-only mode.<br>- **OpenMode.WRITE_ONLY(0o1)**: Open the file in write-only mode.<br>- **OpenMode.READ_WRITE(0o2)**: Open the file in read/write mode.<br>You can also specify the following options, separated by a bitwise OR operator (|). By default, no additional options are given.<br>- **OpenMode.CREATE(0o100)**: If the file does not exist, create it.<br>- **OpenMode.TRUNC(0o1000)**: If the file exists and is open in write-only or read/write mode, truncate the file length to 0.<br>- **OpenMode.APPEND(0o2000)**: Open the file in append mode. New data will be added to the end of the file.<br>- **OpenMode.NONBLOCK(0o4000)**: If **path** points to a named pipe (also known as a FIFO), block special file, or character special file, perform non-blocking operations on the open file and in subsequent I/Os.<br>- **OpenMode.DIR(0o200000)**: If **path** does not point to a directory, throw an exception.<br>- **OpenMode.NOFOLLOW(0o400000)**: If **path** points to a symbolic link, throw an exception.<br>- **OpenMode.SYNC(0o4010000)**: Open the file in synchronous I/O mode.|
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.open(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE, (err, file) => {
if (err) {
console.info("mkdir failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("file fd: " + file.fd);
}
});
```
## fs.openSync
openSync(path: string, mode?: number): File
Synchronously opens a file. File URIs are supported.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the file in the application sandbox or URI of the file. |
| mode | number | No | [Mode](#openmode) for opening the file. You must specify one of the following options. By default, the file is open in read-only mode.<br>- **OpenMode.READ_ONLY(0o0)**: Open the file in read-only mode.<br>- **OpenMode.WRITE_ONLY(0o1)**: Open the file in write-only mode.<br>- **OpenMode.READ_WRITE(0o2)**: Open the file in read/write mode.<br>You can also specify the following options, separated by a bitwise OR operator (|). By default, no additional options are given.<br>- **OpenMode.CREATE(0o100)**: If the file does not exist, create it.<br>- **OpenMode.TRUNC(0o1000)**: If the file exists and is open in write-only or read/write mode, truncate the file length to 0.<br>- **OpenMode.APPEND(0o2000)**: Open the file in append mode. New data will be added to the end of the file.<br>- **OpenMode.NONBLOCK(0o4000)**: If **path** points to a named pipe (also known as a FIFO), block special file, or character special file, perform non-blocking operations on the open file and in subsequent I/Os.<br>- **OpenMode.DIR(0o200000)**: If **path** does not point to a directory, throw an exception.<br>- **OpenMode.NOFOLLOW(0o400000)**: If **path** points to a symbolic link, throw an exception.<br>- **OpenMode.SYNC(0o4010000)**: Open the file in synchronous I/O mode.|
**Return value**
| Type | Description |
| ------ | ----------- |
| [File](#file) | File object opened.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
console.info("file fd: " + file.fd);
fs.closeSync(file);
```
## fs.read
read(fd: number, buffer: ArrayBuffer, options?: { offset?: number; length?: number; }): Promise&lt;number&gt;
Reads data from a file. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ----------- | ---- | ------------------------------------------------------------ |
| fd | number | Yes | FD of the file. |
| buffer | ArrayBuffer | Yes | Buffer used to store the file data read. |
| options | Object | No | The options are as follows:<br>- **offset** (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position.<br>- **length** (number): length of the data to read. This parameter is optional. The default value is the buffer length.|
**Return value**
| Type | Description |
| ---------------------------------- | ------ |
| Promise&lt;number&gt; | Promise used to return the data read.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE);
let buf = new ArrayBuffer(4096);
fs.read(file.fd, buf).then((readLen) => {
console.info("Read file data successfully");
console.info(String.fromCharCode.apply(null, new Uint8Array(readLen)));
fs.closeSync(file);
}).catch((err) => {
console.info("read file data failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.read
read(fd: number, buffer: ArrayBuffer, options?: { offset?: number; length?: number; }, callback: AsyncCallback&lt;number&gt;): void
Reads data from a file. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| -------- | ---------------------------------------- | ---- | ---------------------------------------- |
| fd | number | Yes | FD of the file. |
| buffer | ArrayBuffer | Yes | Buffer used to store the file data read. |
| options | Object | No | The options are as follows:<br>- **offset** (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position.<br>- **length** (number): length of the data to read. This parameter is optional. The default value is the buffer length.|
| callback | AsyncCallback&lt;number&gt; | Yes | Callback invoked when the data is read asynchronously. |
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE);
let buf = new ArrayBuffer(4096);
fs.read(file.fd, buf, (err, readLen) => {
if (err) {
console.info("mkdir failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("Read file data successfully");
console.info(String.fromCharCode.apply(null, new Uint8Array(readLen)));
fs.closeSync(file);
}
});
```
## fs.readSync
readSync(fd: number, buffer: ArrayBuffer, options?: { offset?: number; length?: number; }): number
Synchronously reads data from a file.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ------- | ----------- | ---- | ---------------------------------------- |
| fd | number | Yes | FD of the file. |
| buffer | ArrayBuffer | Yes | Buffer used to store the file data read. |
| options | Object | No | The options are as follows:<br>- **offset** (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position.<br>- **length** (number): length of the data to read. This parameter is optional. The default value is the buffer length.|
**Return value**
| Type | Description |
| ------ | -------- |
| number | Length of the data read.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE);
let buf = new ArrayBuffer(4096);
let num = fs.readSync(file.fd, buf);
fs.closeSync(file);
```
## fs.rmdir
rmdir(path: string): Promise&lt;void&gt;
Deletes a directory. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------------- |
| path | string | Yes | Path of the directory in the application sandbox.|
**Return value**
| Type | Description |
| ------------------- | ---------------------------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
let dirPath = pathDir + '/testDir';
fs.rmdir(dirPath).then(() => {
console.info("Directory deleted");
}).catch((err) => {
console.info("rmdir failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.rmdir
rmdir(path: string, callback: AsyncCallback&lt;void&gt;): void
Deletes a directory. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------- | ---- | -------------------------- |
| path | string | Yes | Path of the directory in the application sandbox.|
| callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked when the directory is deleted asynchronously. |
**Example**
```js
let dirPath = pathDir + '/testDir';
fs.rmdir(dirPath, (err) => {
if (err) {
console.info("rmdir failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("Directory deleted");
}
});
```
## fs.rmdirSync
rmdirSync(path: string): void
Synchronously deletes a directory.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------------- |
| path | string | Yes | Path of the directory in the application sandbox.|
**Example**
```js
let dirPath = pathDir + '/testDir';
fs.rmdirSync(dirPath);
```
## fs.unlink
unlink(path: string): Promise&lt;void&gt;
Deletes a file. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------------- |
| path | string | Yes | Path of the file in the application sandbox.|
**Return value**
| Type | Description |
| ------------------- | ---------------------------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.unlink(filePath).then(() => {
console.info("File deleted");
}).catch((err) => {
console.info("remove file failed with error message: " + err.message + ", error code: " + err.codeor);
});
```
## fs.unlink
unlink(path: string, callback: AsyncCallback&lt;void&gt;): void
Deletes a file. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------- | ---- | -------------------------- |
| path | string | Yes | Path of the file in the application sandbox.|
| callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked when the file is deleted asynchronously. |
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.unlink(filePath, (err) => {
if (err) {
console.info("remove file failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("File deleted");
}
});
```
## fs.unlinkSync
unlinkSync(path: string): void
Synchronously deletes a file.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------------- |
| path | string | Yes | Path of the file in the application sandbox.|
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.unlinkSync(filePath);
```
## fs.write
write(fd: number, buffer: ArrayBuffer|string, options?: { offset?: number; length?: number; encoding?: string; }): Promise&lt;number&gt;
Writes data into a file. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ------- | ------------------------------- | ---- | ---------------------------------------- |
| fd | number | Yes | FD of the file. |
| buffer | ArrayBuffer\|string | Yes | Data to write. It can be a string or data from a buffer. |
| options | Object | No | The options are as follows:<br>- **offset** (number): start position to write the data in the file. This parameter is optional. By default, data is written from the current position.<br>- **length** (number): length of the data to write. This parameter is optional. The default value is the buffer length.<br>- **encoding** (string): format of the data to be encoded when the data is a string. The default value is **'utf-8'**, which is the only value supported.|
**Return value**
| Type | Description |
| --------------------- | -------- |
| Promise&lt;number&gt; | Promise used to return the length of the data written.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
fs.write(file.fd, "hello, world").then((writeLen) => {
console.info("write data to file succeed and size is:" + writeLen);
fs.closeSync(file);
}).catch((err) => {
console.info("write data to file failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.write
write(fd: number, buffer: ArrayBuffer|string, options?: { offset?: number; length?: number; encoding?: string; }, callback: AsyncCallback&lt;number&gt;): void
Writes data into a file. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| -------- | ------------------------------- | ---- | ---------------------------------------- |
| fd | number | Yes | FD of the file. |
| buffer | ArrayBuffer\|string | Yes | Data to write. It can be a string or data from a buffer. |
| options | Object | No | The options are as follows:<br>- **offset** (number): start position to write the data in the file. This parameter is optional. By default, data is written from the current position.<br>- **length** (number): length of the data to write. This parameter is optional. The default value is the buffer length.<br>- **encoding** (string): format of the data to be encoded when the data is a string. The default value is **'utf-8'**, which is the only value supported.|
| callback | AsyncCallback&lt;number&gt; | Yes | Callback invoked when the data is written asynchronously. |
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
fs.write(file.fd, "hello, world", (err, writeLen) => {
if (err) {
console.info("write failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("write data to file succeed and size is:" + writeLen);
fs.closeSync(file);
}
});
```
## fs.writeSync
writeSync(fd: number, buffer: ArrayBuffer|string, options?: { offset?: number; length?: number; encoding?: string; }): number
Synchronously writes data into a file.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ------- | ------------------------------- | ---- | ---------------------------------------- |
| fd | number | Yes | FD of the file. |
| buffer | ArrayBuffer\|string | Yes | Data to write. It can be a string or data from a buffer. |
| options | Object | No | The options are as follows:<br>- **offset** (number): start position to write the data in the file. This parameter is optional. By default, data is written from the current position.<br>- **length** (number): length of the data to write. This parameter is optional. The default value is the buffer length.<br>- **encoding** (string): format of the data to be encoded when the data is a string. The default value is **'utf-8'**, which is the only value supported.|
**Return value**
| Type | Description |
| ------ | -------- |
| number | Length of the data written in the file.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
let writeLen = fs.writeSync(file.fd, "hello, world");
console.info("write data to file succeed and size is:" + writeLen);
fs.closeSync(file);
```
## fs.truncate
truncate(file: string|number, len?: number): Promise&lt;void&gt;
Truncates a file. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------------------- |
| file | string\|number | Yes | Path of the file in the application sandbox or file descriptor (FD) of the file. |
| len | number | No | File length, in bytes, after truncation.|
**Return value**
| Type | Description |
| ------------------- | ---------------------------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let len = 5;
fs.truncate(filePath, len).then(() => {
console.info("File truncated");
}).catch((err) => {
console.info("truncate file failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.truncate
truncate(file: string|number, len?: number, callback: AsyncCallback&lt;void&gt;): void
Truncates a file. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------- | ---- | -------------------------------- |
| file | string\|number | Yes | Path of the file in the application sandbox or file descriptor (FD) of the file. |
| len | number | No | File length, in bytes, after truncation.|
| callback | AsyncCallback&lt;void&gt; | Yes | Callback that returns no value. |
**Example**
```js
let filePath = pathDir + "/test.txt";
let len = 5;
fs.truncate(filePath, len, (err) => {
if (err) {
console.info("truncate failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("truncate success");
}
});
```
## fs.truncateSync
truncateSync(file: string|number, len?: number): void
Synchronously truncates a file.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------------------- |
| file | string\|number | Yes | Path of the file in the application sandbox or file descriptor (FD) of the file. |
| len | number | No | File length, in bytes, after truncation.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let len = 5;
fs.truncateSync(filePath, len);
```
## fs.readText
readText(filePath: string, options?: { offset?: number; length?: number; encoding?: string; }): Promise&lt;string&gt;
Reads the text content of a file. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------ | ---- | ------------------------------------------------------------ |
| filePath | string | Yes | Path of the file in the application sandbox. |
| options | Object | No | The options are as follows:<br>- **offset** (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position.<br>- **length** (number): length of the data to read. This parameter is optional. The default value is the file length.<br>- **encoding** (string): format of the string to be encoded. The default value is **'utf-8'**, which is the only value supported.|
**Return value**
| Type | Description |
| --------------------- | ---------- |
| Promise&lt;string&gt; | Promise used to return the content read.|
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.readText(filePath).then((str) => {
console.info("readText succeed:" + str);
}).catch((err) => {
console.info("readText failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.readText
readText(filePath: string, options?: { offset?: number; length?: number; encoding?: string; }, callback: AsyncCallback&lt;string&gt;): void
Reads the text content of a file. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | --------------------------- | ---- | ------------------------------------------------------------ |
| filePath | string | Yes | Path of the file in the application sandbox. |
| options | Object | No | The options are as follows:<br>- **offset** (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position.<br>- **length** (number): length of the data to read. This parameter is optional. The default value is the file length.<br>- **encoding** (string): format of the string to be encoded. The default value is **'utf-8'**, which is the only value supported.|
| callback | AsyncCallback&lt;string&gt; | Yes | Callback used to return the content read. |
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.readText(filePath, { offset: 1, encoding: 'UTF-8' }, (err, str) => {
if (err) {
console.info("read text failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("readText succeed:" + str);
}
});
```
## fs.readTextSync
readTextSync(filePath: string, options?: { offset?: number; length?: number; encoding?: string; }): string
Synchronously reads the text of a file.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------ | ---- | ------------------------------------------------------------ |
| filePath | string | Yes | Path of the file in the application sandbox. |
| options | Object | No | The options are as follows:<br>- **offset** (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position.<br>- **length** (number): length of the data to read. This parameter is optional. The default value is the file length.<br>- **encoding** (string): format of the string to be encoded. The default value is **'utf-8'**, which is the only value supported.|
**Return value**
| Type | Description |
| ------ | -------------------- |
| string | Promise used to return the content of the file read.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let str = fs.readTextSync(filePath, {offset: 1, length: 3});
console.info("readText succeed:" + str);
```
## fs.lstat
lstat(path: string): Promise&lt;Stat&gt;
Obtains information about a symbolic link. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------------------------- |
| path | string | Yes | Path of the symbolic link in the application sandbox.|
**Return value**
| Type | Description |
| ---------------------------- | ---------- |
| Promise&lt;[Stat](#stat)&gt; | Promise used to return the symbolic link information obtained. For details, see **stat**.|
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.lstat(filePath).then((stat) => {
console.info("get link status succeed, the size of file is" + stat.size);
}).catch((err) => {
console.info("get link status failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.lstat
lstat(path: string, callback: AsyncCallback&lt;Stat&gt;): void
Obtains information about a symbolic link. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ---------------------------------- | ---- | -------------------------------------- |
| path | string | Yes | Path of the symbolic link in the application sandbox.|
| callback | AsyncCallback&lt;[Stat](#stat)&gt; | Yes | Callback used to return the symbolic link information obtained. |
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.lstat(filePath, (err, stat) => {
if (err) {
console.info("lstat failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("get link status succeed, the size of file is" + stat.size);
}
});
```
## fs.lstatSync
lstatSync(path: string): Stat
Obtains information about a symbolic link synchronously.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------------------------- |
| path | string | Yes | Path of the file in the application sandbox.|
**Return value**
| Type | Description |
| ------------- | ---------- |
| [Stat](#stat) | File information obtained.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let stat = fs.lstatSync(filePath);
```
## fs.rename
rename(oldPath: string, newPath: string): Promise&lt;void&gt;
Renames a file. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ------ | ---- | ---------------------------- |
| oldPath | string | Yes | Path of the file to rename in the application sandbox.|
| newPath | string | Yes | Path of the renamed file in the application sandbox. |
**Return value**
| Type | Description |
| ------------------- | ---------------------------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
let srcFile = pathDir + "/test.txt";
let dstFile = pathDir + '/new.txt';
fs.rename(srcFile, dstFile).then(() => {
console.info("File renamed");
}).catch((err) => {
console.info("rename failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.rename
rename(oldPath: string, newPath: string, callback: AsyncCallback&lt;void&gt;): void
Renames a file. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------- | ---- | ---------------------------- |
| oldPath | string | Yes | Path of the file to rename in the application sandbox.|
| newPath | string | Yes | Path of the renamed file in the application sandbox. |
| callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked when the file is asynchronously renamed. |
**Example**
```js
let srcFile = pathDir + "/test.txt";
let dstFile = pathDir + '/new.txt';
fs.rename(srcFile, dstFile, (err) => {
if (err) {
console.info("rename failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("rename success");
}
});
```
## fs.renameSync
renameSync(oldPath: string, newPath: string): void
Synchronously renames a file.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ------ | ---- | ---------------------------- |
| oldPath | string | Yes | Path of the file to rename in the application sandbox.|
| newPath | string | Yes | Path of the renamed file in the application sandbox. |
**Example**
```js
let srcFile = pathDir + "/test.txt";
let dstFile = pathDir + '/new.txt';
fs.renameSync(srcFile, dstFile);
```
## fs.fsync
fsync(fd: number): Promise&lt;void&gt;
Flushes data of a file to disk. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ---- | ------ | ---- | ------------ |
| fd | number | Yes | FD of the file.|
**Return value**
| Type | Description |
| ------------------- | ---------------------------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath);
fs.fsync(file.fd).then(() => {
console.info("Data flushed");
}).catch((err) => {
console.info("sync data failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.fsync
fsync(fd: number, callback: AsyncCallback&lt;void&gt;): void
Flushes data of a file to disk. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| -------- | ------------------------- | ---- | --------------- |
| fd | number | Yes | FD of the file. |
| Callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked when the file data is synchronized in asynchronous mode.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath);
fs.fsync(file.fd, (err) => {
if (err) {
console.info("fsync failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("fsync success");
fs.closeSync(file);
}
});
```
## fs.fsyncSync
fsyncSync(fd: number): void
Flushes data of a file to disk in synchronous mode.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ---- | ------ | ---- | ------------ |
| fd | number | Yes | FD of the file.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath);
fs.fsyncSync(file.fd);
fs.closeSync(file);
```
## fs.fdatasync
fdatasync(fd: number): Promise&lt;void&gt;
Flushes data of a file to disk. This API uses a promise to return the result. **fdatasync()** is similar to **fsync()**, but does not flush modified metadata unless that metadata is needed.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ---- | ------ | ---- | ------------ |
| fd | number | Yes | FD of the file.|
**Return value**
| Type | Description |
| ------------------- | ---------------------------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath);
fs.fdatasync(file.fd).then((err) => {
console.info("Data flushed");
fs.closeSync(file);
}).catch((err) => {
console.info("sync data failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.fdatasync
fdatasync(fd: number, callback: AsyncCallback&lt;void&gt;): void
Flushes data of a file to disk. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| -------- | ------------------------------- | ---- | ----------------- |
| fd | number | Yes | FD of the file. |
| callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked when the file data is synchronized in asynchronous mode.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath);
fs.fdatasync (file.fd, (err) => {
if (err) {
console.info("fdatasync failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("fdatasync success");
fs.closeSync(file);
}
});
```
## fs.fdatasyncSync
fdatasyncSync(fd: number): void
Synchronizes data in a file in synchronous mode.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ---- | ------ | ---- | ------------ |
| fd | number | Yes | FD of the file.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath);
let stat = fs.fdatasyncSync(file.fd);
fs.closeSync(file);
```
## fs.symlink
symlink(target: string, srcPath: string): Promise&lt;void&gt;
Creates a symbolic link based on a file path. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ------ | ---- | ---------------------------- |
| target | string | Yes | Path of the source file in the application sandbox. |
| srcPath | string | Yes | Path of the symbolic link in the application sandbox.|
**Return value**
| Type | Description |
| ------------------- | ---------------------------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
let srcFile = pathDir + "/test.txt";
let dstFile = pathDir + '/test';
fs.symlink(srcFile, dstFile).then(() => {
console.info("Symbolic link created");
}).catch((err) => {
console.info("symlink failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.symlink
symlink(target: string, srcPath: string, callback: AsyncCallback&lt;void&gt;): void
Creates a symbolic link based on a file path. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------- | ---- | -------------------------------- |
| target | string | Yes | Path of the source file in the application sandbox. |
| srcPath | string | Yes | Path of the symbolic link in the application sandbox. |
| callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked when the symbolic link is created asynchronously.|
**Example**
```js
let srcFile = pathDir + "/test.txt";
let dstFile = pathDir + '/test';
fs.symlink(srcFile, dstFile, (err) => {
if (err) {
console.info("symlink failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("symlink success");
}
});
```
## fs.symlinkSync
symlinkSync(target: string, srcPath: string): void
Synchronously creates a symbolic link based on a file path.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ------ | ---- | ---------------------------- |
| target | string | Yes | Path of the source file in the application sandbox. |
| srcPath | string | Yes | Path of the symbolic link in the application sandbox.|
**Example**
```js
let srcFile = pathDir + "/test.txt";
let dstFile = pathDir + '/test';
fs.symlinkSync(srcFile, dstFile);
```
## fs.mkdtemp
mkdtemp(prefix: string): Promise&lt;string&gt;
Creates a temporary directory. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ------ | ------ | ---- | --------------------------- |
| prefix | string | Yes | A randomly generated string used to replace "XXXXXX" in a directory.|
**Return value**
| Type | Description |
| --------------------- | ---------- |
| Promise&lt;string&gt; | Promise used to return the unique directory generated.|
**Example**
```js
fs.mkdtemp(pathDir + "/XXXXXX").then((pathDir) => {
console.info("mkdtemp succeed:" + pathDir);
}).catch((err) => {
console.info("mkdtemp failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.mkdtemp
mkdtemp(prefix: string, callback: AsyncCallback&lt;string&gt;): void
Creates a temporary directory. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| -------- | --------------------------- | ---- | --------------------------- |
| prefix | string | Yes | A randomly generated string used to replace "XXXXXX" in a directory.|
| callback | AsyncCallback&lt;string&gt; | Yes | Callback invoked when a temporary directory is created asynchronously. |
**Example**
```js
fs.mkdtemp(pathDir + "/XXXXXX", (err, res) => {
if (err) {
console.info("mkdtemp failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("mkdtemp success");
}
});
```
## fs.mkdtempSync
mkdtempSync(prefix: string): string
Synchronously creates a temporary directory.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ------ | ------ | ---- | --------------------------- |
| prefix | string | Yes | A randomly generated string used to replace "XXXXXX" in a directory.|
**Return value**
| Type | Description |
| ------ | ---------- |
| string | Unique path generated.|
**Example**
```js
let res = fs.mkdtempSync(pathDir + "/XXXXXX");
```
## fs.createStream
createStream(path: string, mode: string): Promise&lt;Stream&gt;
Opens a file stream based on the file path. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the file in the application sandbox. |
| mode | string | Yes | - **r**: Open a file for reading. The file must exist.<br>- **r+**: Open a file for both reading and writing. The file must exist.<br>- **w**: Open a file for writing. If the file exists, clear its content. If the file does not exist, create a file.<br>- **w+**: Open a file for both reading and writing. If the file exists, clear its content. If the file does not exist, create a file.<br>- **a**: Open a file in append mode for writing at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).<br>- **a+**: Open a file in append mode for reading or updating at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).|
**Return value**
| Type | Description |
| --------------------------------- | --------- |
| Promise&lt;[Stream](#stream)&gt; | Promise used to return the result.|
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.createStream(filePath, "r+").then((stream) => {
console.info("Stream created");
}).catch((err) => {
console.info("createStream failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.createStream
createStream(path: string, mode: string, callback: AsyncCallback&lt;Stream&gt;): void
Opens a file stream based on the file path. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | --------------------------------------- | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the file in the application sandbox. |
| mode | string | Yes | - **r**: Open a file for reading. The file must exist.<br>- **r+**: Open a file for both reading and writing. The file must exist.<br>- **w**: Open a file for writing. If the file exists, clear its content. If the file does not exist, create a file.<br>- **w+**: Open a file for both reading and writing. If the file exists, clear its content. If the file does not exist, create a file.<br>- **a**: Open a file in append mode for writing at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).<br>- **a+**: Open a file in append mode for reading or updating at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).|
| callback | AsyncCallback&lt;[Stream](#stream)&gt; | Yes | Callback invoked when the stream is open asynchronously. |
**Example**
```js
let filePath = pathDir + "/test.txt";
fs.createStream(filePath, "r+", (err, stream) => {
if (err) {
console.info("create stream failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("create stream success");
}
});
```
## fs.createStreamSync
createStreamSync(path: string, mode: string): Stream
Synchronously opens a stream based on the file path.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the file in the application sandbox. |
| mode | string | Yes | - **r**: Open a file for reading. The file must exist.<br>- **r+**: Open a file for both reading and writing. The file must exist.<br>- **w**: Open a file for writing. If the file exists, clear its content. If the file does not exist, create a file.<br>- **w+**: Open a file for both reading and writing. If the file exists, clear its content. If the file does not exist, create a file.<br>- **a**: Open a file in append mode for writing at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).<br>- **a+**: Open a file in append mode for reading or updating at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).|
**Return value**
| Type | Description |
| ------------------ | --------- |
| [Stream](#stream) | Stream opened.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss = fs.createStreamSync(filePath, "r+");
```
## fs.fdopenStream
fdopenStream(fd: number, mode: string): Promise&lt;Stream&gt;
Opens a file stream based on the file descriptor. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ---- | ------ | ---- | ---------------------------------------- |
| fd | number | Yes | FD of the file. |
| mode | string | Yes | - **r**: Open a file for reading. The file must exist.<br>- **r+**: Open a file for both reading and writing. The file must exist.<br>- **w**: Open a file for writing. If the file exists, clear its content. If the file does not exist, create a file.<br>- **w+**: Open a file for both reading and writing. If the file exists, clear its content. If the file does not exist, create a file.<br>- **a**: Open a file in append mode for writing at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).<br>- **a+**: Open a file in append mode for reading or updating at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).|
**Return value**
| Type | Description |
| --------------------------------- | --------- |
| Promise&lt;[Stream](#stream)&gt; | Promise used to return the result.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath);
fs.fdopenStream(file.fd, "r+").then((stream) => {
console.info("Stream opened");
fs.closeSync(file);
}).catch((err) => {
console.info("openStream failed with error message: " + err.message + ", error code: " + err.code);
});
```
## fs.fdopenStream
fdopenStream(fd: number, mode: string, callback: AsyncCallback&lt;Stream&gt;): void
Opens a file stream based on the file descriptor. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| -------- | ---------------------------------------- | ---- | ---------------------------------------- |
| fd | number | Yes | FD of the file. |
| mode | string | Yes | - **r**: Open a file for reading. The file must exist.<br>- **r+**: Open a file for both reading and writing. The file must exist.<br>- **w**: Open a file for writing. If the file exists, clear its content. If the file does not exist, create a file.<br>- **w+**: Open a file for both reading and writing. If the file exists, clear its content. If the file does not exist, create a file.<br>- **a**: Open a file in append mode for writing at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).<br>- **a+**: Open a file in append mode for reading or updating at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).|
| callback | AsyncCallback&lt;[Stream](#stream)&gt; | Yes | Callback invoked when the stream is open asynchronously. |
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath, fs.OpenMode.READ_ONLY);
fs.fdopenStream(file.fd, "r+", (err, stream) => {
if (err) {
console.info("fdopen stream failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("fdopen stream success");
fs.closeSync(file);
}
});
```
## fs.fdopenStreamSync
fdopenStreamSync(fd: number, mode: string): Stream
Synchronously opens a stream based on the file descriptor.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ---- | ------ | ---- | ---------------------------------------- |
| fd | number | Yes | FD of the file. |
| mode | string | Yes | - **r**: Open a file for reading. The file must exist.<br>- **r+**: Open a file for both reading and writing. The file must exist.<br>- **w**: Open a file for writing. If the file exists, clear its content. If the file does not exist, create a file.<br>- **w+**: Open a file for both reading and writing. If the file exists, clear its content. If the file does not exist, create a file.<br>- **a**: Open a file in append mode for writing at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).<br>- **a+**: Open a file in append mode for reading or updating at the end of the file. If the file does not exist, create a file. If the file exists, write data to the end of the file (the original content of the file is reserved).|
**Return value**
| Type | Description |
| ------------------ | --------- |
| [Stream](#stream) | Stream opened.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let file = fs.openSync(filePath, fs.OpenMode.READ_ONLY | fs.OpenMode.CREATE);
let ss = fs.fdopenStreamSync(file.fd, "r+");
fs.closeSync(file);
```
## Stat
Represents detailed file information. Before calling any API of the **Stat()** class, use [stat()](#fsstat) to create a **Stat** instance synchronously or asynchronously.
**System capability**: SystemCapability.FileManagement.File.FileIO
### Attributes
| Name | Type | Readable | Writable | Description |
| ------ | ------ | ---- | ---- | ---------------------------------------- |
| ino | number | Yes | No | File ID. Different files on the same device have different **ino**s.| |
| mode | number | Yes | No | File permissions. The meaning of each bit is as follows:<br>- **0o400**: The owner has the read permission on a regular file or a directory entry.<br>- **0o200**: The owner has the permission to write a regular file or create and delete a directory entry.<br>- **0o100**: The owner has the permission to execute a regular file or search for the specified path in a directory.<br>- **0o040**: The user group has the read permission on a regular file or a directory entry.<br>- **0o020**: The user group has the permission to write a regular file or create and delete a directory entry.<br>- **0o010**: The user group has the permission to execute a regular file or search for the specified path in a directory.<br>- **0o004**: Other users have the permission to read a regular file or read a directory entry.<br>- **0o002**: Other users have the permission to write a regular file or create and delete a directory entry.<br>- **0o001**: Other users have the permission to execute a regular file or search for the specified path in a directory.|
| uid | number | Yes | No | ID of the file owner.|
| gid | number | Yes | No | ID of the user group of the file.|
| size | number | Yes | No | File size, in bytes. This parameter is valid only for regular files. |
| atime | number | Yes | No | Time of the last access to the file. The value is the number of seconds elapsed since 00:00:00 on January 1, 1970. |
| mtime | number | Yes | No | Time of the last modification to the file. The value is the number of seconds elapsed since 00:00:00 on January 1, 1970. |
| ctime | number | Yes | No | Time of the last status change of the file. The value is the number of seconds elapsed since 00:00:00 on January 1, 1970. |
### isBlockDevice
isBlockDevice(): boolean
Checks whether this file is a block special file. A block special file supports access by block only, and it is cached when accessed.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Return value**
| Type | Description |
| ------- | ---------------- |
| boolean | Whether the file is a block special file.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let isBLockDevice = fs.statSync(filePath).isBlockDevice();
```
### isCharacterDevice
isCharacterDevice(): boolean
Checks whether this file is a character special file. A character special file supports random access, and it is not cached when accessed.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Return value**
| Type | Description |
| ------- | ----------------- |
| boolean | Whether the file is a character special file.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let isCharacterDevice = fs.statSync(filePath).isCharacterDevice();
```
### isDirectory
isDirectory(): boolean
Checks whether this file is a directory.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Return value**
| Type | Description |
| ------- | ------------- |
| boolean | Whether the file is a directory.|
**Example**
```js
let dirPath = pathDir + "/test";
let isDirectory = fs.statSync(dirPath).isDirectory();
```
### isFIFO
isFIFO(): boolean
Checks whether this file is a named pipe (or FIFO). Named pipes are used for inter-process communication.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Return value**
| Type | Description |
| ------- | --------------------- |
| boolean | Whether the file is a FIFO.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let isFIFO = fs.statSync(filePath).isFIFO();
```
### isFile
isFile(): boolean
Checks whether this file is a regular file.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Return value**
| Type | Description |
| ------- | --------------- |
| boolean | Whether the file is a regular file.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let isFile = fs.statSync(filePath).isFile();
```
### isSocket
isSocket(): boolean
Checks whether this file is a socket.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Return value**
| Type | Description |
| ------- | -------------- |
| boolean | Whether the file is a socket.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let isSocket = fs.statSync(filePath).isSocket();
```
### isSymbolicLink
isSymbolicLink(): boolean
Checks whether this file is a symbolic link.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Return value**
| Type | Description |
| ------- | --------------- |
| boolean | Whether the file is a symbolic link.|
**Example**
```js
let filePath = pathDir + "/test";
let isSymbolicLink = fs.statSync(filePath).isSymbolicLink();
```
## Stream
Provides file stream management. Before calling any API of the **Stream** class, use **createStream()** to create a **Stream** instance synchronously or asynchronously.
### close
close(): Promise&lt;void&gt;
Closes the stream. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Return value**
| Type | Description |
| ------------------- | ------------- |
| Promise&lt;void&gt; | Promise used to return the stream close result.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss= fs.createStreamSync(filePath, "r+");
ss.close().then(() => {
console.info("File stream closed");
}).catch((err) => {
console.info("close fileStream failed with error message: " + err.message + ", error code: " + err.code);
});
```
### close
close(callback: AsyncCallback&lt;void&gt;): void
Closes the stream. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| -------- | ------------------------- | ---- | ------------- |
| callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked when the stream is closed asynchronously.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss= fs.createStreamSync(filePath, "r+");
ss.close((err) => {
if (err) {
console.info("close stream failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("close stream success"):
}
});
```
### closeSync
closeSync(): void
Synchronously closes the stream.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss= fs.createStreamSync(filePath, "r+");
ss.closeSync();
```
### flush
flush(): Promise&lt;void&gt;
Flushes the stream. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Return value**
| Type | Description |
| ------------------- | ------------- |
| Promise&lt;void&gt; | Promise used to return the stream flushing result.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss= fs.createStreamSync(filePath, "r+");
ss.flush().then(() => {
console.info("Stream flushed");
}).catch((err) => {
console.info("flush failed with error message: " + err.message + ", error code: " + err.code);
});
```
### flush
flush(callback: AsyncCallback&lt;void&gt;): void
Flushes the stream. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| -------- | ------------------------- | ---- | -------------- |
| callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked when the stream is asynchronously flushed.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss= fs.createStreamSync(filePath, "r+");
ss.flush((err) => {
if (err) {
console.info("flush stream failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("flush success");
}
});
```
### flushSync
flushSync(): void
Synchronously flushes the stream.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss= fs.createStreamSync(filePath, "r+");
ss.flushSync();
```
### write
write(buffer: ArrayBuffer|string, options?: { offset?: number; length?: number; encoding?: string; }): Promise&lt;number&gt;
Writes data into the stream. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ------- | ------------------------------- | ---- | ---------------------------------------- |
| buffer | ArrayBuffer\|string | Yes | Data to write. It can be a string or data from a buffer. |
| options | Object | No | The options are as follows:<br>- **length** (number): length of the data to write. The default value is the buffer length.<br>- **offset** (number): start position to write the data in the file. This parameter is optional. By default, data is written from the current position.<br>- **encoding** (string): format of the data to be encoded when the data is a string. The default value is **'utf-8'**, which is the only value supported.|
**Return value**
| Type | Description |
| --------------------- | -------- |
| Promise&lt;number&gt; | Promise used to return the length of the data written.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss= fs.createStreamSync(filePath, "r+");
ss.write("hello, world",{ offset: 5, length: 5, encoding: 'utf-8' }).then((number) => {
console.info("write succeed and size is:" + number);
}).catch((err) => {
console.info("write failed with error message: " + err.message + ", error code: " + err.code);
});
```
### write
write(buffer: ArrayBuffer|string, options?: { offset?: number; length?: number; encoding?: string; }, callback: AsyncCallback&lt;number&gt;): void
Writes data into the stream. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------------- | ---- | ------------------------------------------------------------ |
| buffer | ArrayBuffer\|string | Yes | Data to write. It can be a string or data from a buffer. |
| options | Object | No | The options are as follows:<br>- **length** (number): length of the data to write. This parameter is optional. The default value is the buffer length.<br>- **offset** (number): start position to write the data in the file. This parameter is optional. By default, data is written from the current position.<br>- **encoding** (string): format of the data to be encoded when the data is a string. The default value is **'utf-8'**, which is the only value supported.|
| callback | AsyncCallback&lt;number&gt; | Yes | Callback invoked when the data is written asynchronously. |
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss= fs.createStreamSync(filePath, "r+");
ss.write("hello, world", { offset: 5, length: 5, encoding :'utf-8'}, (err, bytesWritten) => {
if (err) {
console.info("write stream failed with error message: " + err.message + ", error code: " + err.code);
} else {
if (bytesWritten) {
console.info("write succeed and size is:" + bytesWritten);
}
}
});
```
### writeSync
writeSync(buffer: ArrayBuffer|string, options?: { offset?: number; length?: number; encoding?: string; }): number
Synchronously writes data into the stream.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ------- | ------------------------------- | ---- | ---------------------------------------- |
| buffer | ArrayBuffer\|string | Yes | Data to write. It can be a string or data from a buffer. |
| options | Object | No | The options are as follows:<br>- **length** (number): length of the data to write. This parameter is optional. The default value is the buffer length.<br>- **offset** (number): start position to write the data in the file. This parameter is optional. By default, data is written from the current position.<br>- **encoding** (string): format of the data to be encoded when the data is a string. The default value is **'utf-8'**, which is the only value supported.|
**Return value**
| Type | Description |
| ------ | -------- |
| number | Length of the data written in the file.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss= fs.createStreamSync(filePath,"r+");
let num = ss.writeSync("hello, world", {offset: 5, length: 5, encoding :'utf-8'});
```
### read
read(buffer: ArrayBuffer, options?: { offset?: number; length?: number; }): Promise&lt;number&gt;
Reads data from the stream. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ------- | ----------- | ---- | ---------------------------------------- |
| buffer | ArrayBuffer | Yes | Buffer used to store the file read. |
| options | Object | No | The options are as follows:<br>- **length** (number): length of the data to read. This parameter is optional. The default value is the buffer length.<br>- **offset** (number): position of the data to read in the file. By default, data is read from the current position.|
**Return value**
| Type | Description |
| ---------------------------------- | ------ |
| Promise&lt;number&gt; | Promise used to return the data read.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss = fs.createStreamSync(filePath, "r+");
let buf = new ArrayBuffer(4096);
ss.read(buf, {offset: 5, length: 5}).then((readLen) => {
console.info("Read data successfully");
console.log(String.fromCharCode.apply(null, new Uint8Array(buf)));
}).catch((err) => {
console.info("read data failed with error message: " + err.message + ", error code: " + err.code);
});
```
### read
read(buffer: ArrayBuffer, options?: { position?: number; offset?: number; length?: number; }, callback: AsyncCallback&lt;number&gt;): void
Reads data from the stream. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| -------- | ---------------------------------------- | ---- | ---------------------------------------- |
| buffer | ArrayBuffer | Yes | Buffer used to store the file read. |
| options | Object | No | The options are as follows:<br>- **length** (number): length of the data to read. This parameter is optional. The default value is the buffer length.<br>- **offset** (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position.|
| callback | AsyncCallback&lt;number&gt; | Yes | Callback invoked when data is read asynchronously from the stream. |
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss = fs.createStreamSync(filePath, "r+");
let buf = new ArrayBuffer(4096)
ss.read(buf, {offset: 5, length: 5}, (err, readLen) => {
if (err) {
console.info("read stream failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("Read data successfully");
console.log(String.fromCharCode.apply(null, new Uint8Array(buf)));
}
});
```
### readSync
readSync(buffer: ArrayBuffer, options?: { offset?: number; length?: number; }): number
Synchronously reads data from the stream.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory | Description |
| ------- | ----------- | ---- | ---------------------------------------- |
| buffer | ArrayBuffer | Yes | Buffer used to store the file read. |
| options | Object | No | The options are as follows:<br>- **length** (number): length of the data to read. This parameter is optional. The default value is the buffer length.<br>- **offset** (number): position of the data to read in the file. This parameter is optional. By default, data is read from the current position.<br> |
**Return value**
| Type | Description |
| ------ | -------- |
| number | Length of the data read.|
**Example**
```js
let filePath = pathDir + "/test.txt";
let ss = fs.createStreamSync(filePath, "r+");
let num = ss.readSync(new ArrayBuffer(4096), {offset: 5, length: 5});
```
## File
Represents a **File** object opened by **open()**.
**System capability**: SystemCapability.FileManagement.File.FileIO
### Attributes
| Name | Type | Readable | Writable | Description |
| ---- | ------ | ---- | ---- | ------- |
| fd | number | Yes | No | FD of the file.|
## OpenMode
Defines the constants of the **mode** parameter used in **open()**. It species the mode for opening a file.
**System capability**: SystemCapability.FileManagement.File.FileIO
| Name | Type | Value | Description |
| ---- | ------ |---- | ------- |
| READ_ONLY | number | 0o0 | Open the file in read-only mode.|
| WRITE_ONLY | number | 0o1 | Open the file in write-only mode.|
| READ_WRITE | number | 0o2 | Open the file in read/write mode.|
| CREATE | number | 0o100 | Create a file if the specified file does not exist.|
| TRUNC | number | 0o1000 | If the file exists and is open in write-only or read/write mode, truncate the file length to 0.|
| APPEND | number | 0o2000 | Open the file in append mode. New data will be written to the end of the file.|
| NONBLOCK | number | 0o4000 | If **path** points to a named pipe (FIFO), block special file, or character special file, perform non-blocking operations on the open file and in subsequent I/Os.|
| DIR | number | 0o200000 | If **path** does not point to a directory, throw an exception.|
| NOFOLLOW | number | 0o400000 | If **path** points to a symbolic link, throw an exception.|
| SYNC | number | 0o4010000 | Open the file in synchronous I/O mode.|
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# @ohos.file.hash (File Hash Processing)
The **fileHash** module implements hash processing on files.
> **NOTE**
>
> - The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
> - The APIs of this module support processing of error codes. For details, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).
## Modules to Import
```js
import Hash from '@ohos.file.hash';
```
## Guidelines
Before using the APIs provided by this module to perform operations on a file or directory, obtain the path of the file or directory in the application sandbox as follows:
**Stage Model**
```js
import UIAbility from '@ohos.app.ability.UIAbility';
export default class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage) {
let context = this.context;
let pathDir = context.filesDir;
}
}
```
**FA Model**
```js
import featureAbility from '@ohos.ability.featureAbility';
let context = featureAbility.getContext();
context.getFilesDir().then((data) => {
let pathDir = data;
})
```
For details about how to obtain the FA model context, see [Context](js-apis-inner-app-context.md#context).
## Hash.hash
hash(path: string, algorithm: string): Promise&lt;string&gt;
Calculates a hash value for a file. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | ------ | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the file in the application sandbox. |
| algorithm | string | Yes | Algorithm used to calculate the hash value. The value can be **md5**, **sha1**, or **sha256**. **sha256** is recommended for security purposes.|
**Return value**
| Type | Description |
| --------------------- | -------------------------- |
| Promise&lt;string&gt; | Promise used to return the hash value. The hash value is a hexadecimal string consisting of digits and uppercase letters.|
**Example**
```js
let filePath = pathDir + "/test.txt";
Hash.hash(filePath, "sha256").then((str) => {
console.info("calculate file hash succeed:" + str);
}).catch((err) => {
console.info("calculate file hash failed with error message: " + err.message + ", error code: " + err.code);
});
```
## Hash.hash
hash(path: string, algorithm: string, callback: AsyncCallback&lt;string&gt;): void
Calculates a hash value for a file. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | --------------------------- | ---- | ------------------------------------------------------------ |
| path | string | Yes | Path of the file in the application sandbox. |
| algorithm | string | Yes | Algorithm used to calculate the hash value. The value can be **md5**, **sha1**, or **sha256**. **sha256** is recommended for security purposes.|
| callback | AsyncCallback&lt;string&gt; | Yes | Callback used to return the hash value obtained. The hash value is a hexadecimal string consisting of digits and uppercase letters.|
**Example**
```js
Hash.hash(filePath, "sha256", (err, str) => {
if (err) {
console.info("calculate file hash failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("calculate file hash succeed:" + str);
}
});
```
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# @ohos.file.securityLabel (Data Label)
The **securityLabel** module provides APIs for managing data security levels of files, including obtaining and setting file security levels.
> **NOTE**
>
> - The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
>- The APIs of this module support processing of error codes. For details, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).
## Modules to Import
```js
import securityLabel from '@ohos.file.securityLabel';
```
## Guidelines
Before using the APIs provided by this module to perform operations on files or directories, obtain the path of the file or directory in the application sandbox as follows:
**Stage Model**
```js
import UIAbility from '@ohos.app.ability.UIAbility';
export default class EntryAbility extends UIAbility {
onWindowStageCreate(windowStage) {
let context = this.context;
let pathDir = context.filesDir;
}
}
```
**FA Model**
```js
import featureAbility from '@ohos.ability.featureAbility';
let context = featureAbility.getContext();
context.getFilesDir().then((data) => {
let pathDir = data;
})
```
For details about how to obtain the FA model context, see [Context](js-apis-inner-app-context.md#context).
## securityLabel.setSecurityLabel
setSecurityLabel(path:string, type:dataLevel):Promise&lt;void&gt;
Sets a security label for a file in asynchronous mode. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | ------ | ---- | -------------------------------------------- |
| path | string | Yes | Path of the target file. |
| type | dataLevel | Yes | File security level to set, which can be **s0**, **s1**, **s2**, **s3**, or **s4**.|
**Return value**
| Type | Description |
| ------------------- | ---------------- |
| Promise&lt;void&gt; | Promise that returns no value.|
**Example**
```js
securityLabel.setSecurityLabel(path, "s0").then(() => {
console.info("setSecurityLabel successfully");
}).catch((err) => {
console.info("setSecurityLabel failed with error message: " + err.message + ", error code: " + err.code);
});
```
## securityLabel.setSecurityLabel
setSecurityLabel(path:string, type:dataLevel, callback: AsyncCallback&lt;void&gt;):void
Sets a security label for a file in asynchronous mode. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | ------------------------- | ---- | -------------------------------------------- |
| path | string | Yes | Path of the target file. |
| type | dataLevel | Yes | File security level to set, which can be **s0**, **s1**, **s2**, **s3**, or **s4**.|
| callback | AsyncCallback&lt;void&gt; | Yes | Callback invoked to return the result. |
**Example**
```js
securityLabel.setSecurityLabel(path, "s0", (err) => {
if (err) {
console.info("setSecurityLabel failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("setSecurityLabel successfully.");
}
});
```
## securityLabel.setSecurityLabelSync
setSecurityLabelSync(path:string, type:dataLevel):void
Sets a security label for a file in synchronous mode.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | ------ | ---- | -------------------------------------------- |
| path | string | Yes | Path of the target file. |
| type | dataLevel | Yes | File security level to set, which can be **s0**, **s1**, **s2**, **s3**, or **s4**.|
**Example**
```js
securityLabel.setSecurityLabelSync(path, "s0");
```
## securityLabel.getSecurityLabel
getSecurityLabel(path:string):Promise&lt;string&gt;
Obtains the security label of a file in asynchronous mode. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------- |
| path | string | Yes | Path of the target file.|
**Return value**
| Type | Description |
| --------------------- | ------------ |
| Promise&lt;string&gt; | Security label obtained.|
**Example**
```js
securityLabel.getSecurityLabel(path).then((type) => {
console.log("getSecurityLabel successfully, Label: " + type);
}).catch((err) => {
console.log("getSecurityLabel failed with error message: " + err.message + ", error code: " + err.code);
});
```
## securityLabel.getSecurityLabel
getSecurityLabel(path:string, callback:AsyncCallback&lt;string&gt;): void
Obtains the security label of a file in asynchronous mode. This API uses a callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | --------------------------- | ---- | -------------------------- |
| path | string | Yes | Path of the target file. |
| callback | AsyncCallback&lt;string&gt; | Yes | Callback invoked to return the security label obtained.|
**Example**
```js
securityLabel.getSecurityLabel(path, (err, type) => {
if (err) {
console.log("getSecurityLabel failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.log("getSecurityLabel successfully, Label: " + type);
}
});
```
## securityLabel.getSecurityLabelSync
getSecurityLabelSync(path:string):string
Obtains the security label of a file in synchronous mode.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------- |
| path | string | Yes | Path of the target file.|
**Return value**
| Type | Description |
| ------ | ------------ |
| string | Security label obtained.|
**Example**
```js
let type = securityLabel.getSecurityLabelSync(path);
console.log("getSecurityLabel successfully, Label: " + type);
```
en/application-dev/reference/apis/js-apis-file-statvfs.md 0 → 100644
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# @ohos.file.statvfs (File System Space Statistics)
The **statfs** module provides APIs for obtaining file system information, including the total number of bytes and the number of idle bytes of the file system.
> **NOTE**
>
> - The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
> - The APIs of this module support processing of error codes. For details, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).
## Modules to Import
```js
import statvfs from '@ohos.file.statvfs';
```
## statvfs.getFreeSize
getFreeSize(path:string):Promise&lt;number&gt;
Obtains the number of free bytes of the specified file system in asynchronous mode. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------------------- |
| path | string | Yes | File path of the file system.|
**Return value**
| Type | Description |
| --------------------- | -------------- |
| Promise&lt;number&gt; | Promise used to return the number of free bytes obtained.|
**Example**
```js
let path = "/dev";
statfs.getFreeSize(path).then((number) => {
console.info("getFreeSize promise successfully, Size: " + number);
}).catch((err) => {
console.info("getFreeSize failed with error message: " + err.message + ", error code: " + err.code);
});
```
## statfs.getFreeSize
getFreeSize(path:string, callback:AsyncCallback&lt;number&gt;): void
Obtains the number of free bytes of the specified file system in asynchronous mode. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | --------------------------- | ---- | ---------------------------- |
| path | string | Yes | File path of the file system.|
| callback | AsyncCallback&lt;number&gt; | Yes | Callback invoked to return the number of free bytes obtained.|
**Example**
```js
let path = "/dev";
statfs.getFreeSize(path, (err, number) => {
if (err) {
console.info("getFreeSize failed with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("getFreeSize callback successfully, Size: " + number);
}
});
```
## statfs.getTotalSize
getTotalSize(path: string): Promise&lt;number&gt;
Obtains the total number of bytes of the specified file system in asynchronous mode. This API uses a promise to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name| Type | Mandatory| Description |
| ---- | ------ | ---- | ---------------------------- |
| path | string | Yes | File path of the file system.|
**Return value**
| Type | Description |
| --------------------- | ------------ |
| Promise&lt;number&gt; | Promise used to return the total number of bytes obtained.|
**Example**
```js
let path = "/dev";
statfs.getTotalSize(path).then((number) => {
console.info("getTotalSize promise successfully, Size: " + number);
}).catch((err) => {
console.info("getTotalSize with error message: " + err.message + ", error code: " + err.code);
});
```
## statfs.getTotalSize
getTotalSize(path: string, callback: AsyncCallback&lt;number&gt;): void
Obtains the total number of bytes of the specified file system in asynchronous mode. This API uses an asynchronous callback to return the result.
**System capability**: SystemCapability.FileManagement.File.FileIO
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | --------------------------- | ---- | ---------------------------- |
| path | string | Yes | File path of the file system.|
| callback | AsyncCallback&lt;number&gt; | Yes | Callback invoked to return the total number of bytes obtained. |
**Example**
```js
let path = "/dev";
statfs.getTotalSize(path, (err, number) => {
if (err) {
console.info("getTotalSize with error message: " + err.message + ", error code: " + err.code);
} else {
console.info("getTotalSize promise successfully, Size: " + number);
}
});
```
en/application-dev/reference/apis/js-apis-statfs.md
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# @ohos.statfs (statfs)
The statfs module provides APIs for obtaining file system information, including the total number of bytes and the number of idle bytes of the file system.
The **statfs** module provides APIs for obtaining file system information, including the total number of bytes and the number of idle bytes of the file system.
> **NOTE**<br>
> The initial APIs of this module are supported since API version 8. Newly added APIs will be marked with a superscript to indicate their earliest API version.
> **NOTE**
>
> - The initial APIs of this module are supported since API version 8. Newly added APIs will be marked with a superscript to indicate their earliest API version.
>
> - The APIs provided by this module are deprecated since API version 9. You are advised to use [@ohos.file.statvfs](js-apis-file-statvfs.md).
## Modules to Import
......@@ -20,15 +23,15 @@ Obtains the number of free bytes of the specified file system in asynchronous mo
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------------------- |
| path | string | Yes | File path of the file system.|
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------------------- |
| path | string | Yes | File path of the file system.|
**Return value**
| Type | Description |
| --------------------- | -------------- |
| Promise&lt;number&gt; | Promise used to return the number of free bytes obtained.|
| Type | Description |
| --------------------- | -------------- |
| Promise&lt;number&gt; | Promise used to return the number of free bytes obtained.|
**Example**
......@@ -51,10 +54,10 @@ Obtains the number of free bytes of the specified file system in asynchronous mo
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | --------------------------- | ---- | ---------------------------- |
| path | string | Yes | File path of the file system.|
| callback | AsyncCallback&lt;number&gt; | Yes | Callback invoked to return the number of free bytes obtained.|
| Name | Type | Mandatory| Description |
| -------- | --------------------------- | ---- | ---------------------------- |
| path | string | Yes | File path of the file system.|
| callback | AsyncCallback&lt;number&gt; | Yes | Callback invoked to return the number of free bytes obtained.|
**Example**
......@@ -78,15 +81,15 @@ Obtains the total number of bytes of the specified file system in asynchronous m
**Parameters**
| Name| Type | Mandatory| Description |
| ---- | ------ | ---- | ---------------------------- |
| path | string | Yes | File path of the file system.|
| Name| Type | Mandatory| Description |
| ---- | ------ | ---- | ---------------------------- |
| path | string | Yes | File path of the file system.|
**Return value**
| Type | Description |
| --------------------- | ------------ |
| Promise&lt;number&gt; | Promise used to return the total number of bytes obtained.|
| Type | Description |
| --------------------- | ------------ |
| Promise&lt;number&gt; | Promise used to return the total number of bytes obtained.|
**Example**
......@@ -109,10 +112,10 @@ Obtains the total number of bytes of the specified file system in asynchronous m
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | --------------------------- | ---- | ---------------------------- |
| path | string | Yes | File path of the file system.|
| callback | AsyncCallback&lt;number&gt; | Yes | Callback invoked to return the total number of bytes obtained. |
| Name | Type | Mandatory| Description |
| -------- | --------------------------- | ---- | ---------------------------- |
| path | string | Yes | File path of the file system.|
| callback | AsyncCallback&lt;number&gt; | Yes | Callback invoked to return the total number of bytes obtained. |
**Example**
......
en/application-dev/reference/errorcodes/errorcode-filemanagement.md
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# File Management Error Codes
The error codes of the file management subsystem consist of the following:
- Basic file I/O error codes
- User data management error codes
- User file access error codes
- Spatial statistics error codes
The error codes of the file management subsystem consist of the following:<br>- Basic file I/O error codes<br>- User data management error codes<br>- User file access error codes<br>- Spatial statistics error codes
## Basic File I/O Error Codes
......@@ -719,3 +714,41 @@ Fail to notify agent
**Solution**
Check whether the client is normal.
## Error Code Adaptation
The APIs provided by the file management subsystem support exception handling.
Sample code for exception handling in a synchronous API:
```js
import fs from '@ohos.file.fs'
try {
let file = fs.openSync(path, fs.OpenMode.READ_ONLY);
} catch (err) {
console.error("openSync errCode:" + err.code + ", errMessage:" + err.message);
}
```
Sample code for exception handling in an asynchronous API (promise):
```js
import fs from '@ohos.file.fs'
try {
let file = await fs.open(path, fs.OpenMode.READ_ONLY);
} catch (err) {
console.error("open promise errCode:" + err.code + ", errMessage:" + err.message);
}
```
Sample code for exception handling in an asynchronous API (callback):
```js
import fs from '@ohos.file.fs'
try {
fs.open(path, fs.OpenMode.READ_ONLY, function(e, file){ // Asynchronous thread (such as the system call) errors are obtained via a callback.
if (e) {
console.error("open in async errCode:" + e.code + ", errMessage:" + e.message);
}
});
} catch (err) {// Main thread errors (such as invalid parameters) are obtained by try catch.
console.error("open callback errCode:" + err.code + ", errMessage:" + err.message);
}
```
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