js-apis-config-policy.md

# Configuration Policy

> **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 of this module are system APIs and cannot be called by third-party applications.

The configuration policy provides the capability of obtaining the custom configuration directory and file path based on the predefined custom configuration level.

## Modules to Import

```js
import configPolicy from '@ohos.configPolicy';
```

## getOneCfgFile

getOneCfgFile(relPath: string, callback: AsyncCallback<string>): void

Obtains the path of a configuration file with the specified name and highest priority. This API uses an asynchronous callback to return the result.
For example, if the **config.xml** file is stored in **/system/etc/config.xml** and **/sys-pod/etc/config.xml** (in ascending order of priority), then **/sys-pod/etc/config.xml** is returned.

**System capability**: SystemCapability.Customization.ConfigPolicy

**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| relPath | string | Yes| Name of the configuration file.|
| callback | AsyncCallback<string> | Yes| Callback used to return the path of the configuration file.|

**Example**
  ```js
  configPolicy.getOneCfgFile('config.xml', (error, value) => {
      if (error == undefined) {
          console.log("value is " + value);
      } else {
          console.log("error occurs "+ error);
      }
  });
  ```


## getOneCfgFile

getOneCfgFile(relPath: string): Promise<string>

Obtains the path of a configuration file with the specified name and highest priority. This API uses a promise to return the result.

**System capability**: SystemCapability.Customization.ConfigPolicy

**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| relPath | string | Yes| Name of the configuration file.|

**Return value**
| Type| Description|
| -------- | -------- |
| Promise<string> | Promise used to return the path of the configuration file.|

**Example**
  ```js
  configPolicy.getOneCfgFile('config.xml').then(value => {
      console.log("value is " + value);
  }).catch(error => {
      console.log("getOneCfgFile promise " + error);
  });
  ```


## getCfgFiles

getCfgFiles(relPath: string, callback: AsyncCallback<Array<string>>): void

Obtains all configuration files with the specified name and lists them in ascending order of priority. This API uses an asynchronous callback to return the result. For example, if the **config.xml** file is stored in **/system/etc/config.xml**
and **/sys-pod/etc/config.xml**, then **/system/etc/config.xml, /sys-pod/etc/config.xml** is returned.

**System capability**: SystemCapability.Customization.ConfigPolicy

**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| relPath | string | Yes| Name of the configuration file.|
| callback | AsyncCallback<Array<string>> | Yes| Callback used to return the file list.|

**Example**
  ```js
  configPolicy.getCfgFiles('config.xml', (error, value) => {
      if (error == undefined) {
          console.log("value is " + value);
      } else {
          console.log("error occurs "+ error);
      }
  });
  ```


## getCfgFiles

getCfgFiles(relPath: string): Promise<Array<string>>

Obtains all configuration files with the specified name and lists them in ascending order of priority. This API uses a promise to return the result.

**System capability**: SystemCapability.Customization.ConfigPolicy

**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| relPath | string | Yes| Name of the configuration file.|

**Return value**
| Type| Description|
| -------- | -------- |
| Promise<Array<string>> | Promise used to return the file list.|

**Example**
  ```js
  configPolicy.getCfgFiles('config.xml').then(value => {
      console.log("value is " + value);
  }).catch(error => {
      console.log("getCfgFiles promise " + error);
  });
  ```


## getCfgDirList

getCfgDirList(callback: AsyncCallback<Array<string>>): void

Obtains the configuration level directory list. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.Customization.ConfigPolicy

**Parameters**
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback<Array<string>> | Yes| Callback used to return the configuration level directory list.|

**Example**
  ```js
  configPolicy.getCfgDirList((error, value) => {
      if (error == undefined) {
          console.log("value is " + value);
      } else {
          console.log("error occurs "+ error);
      }
  });
  ```


## getCfgDirList

getCfgDirList(): Promise<Array<string>>

Obtains the configuration level directory list. This API uses a promise to return the result.

**System capability**: SystemCapability.Customization.ConfigPolicy

**Return value**
| Type| Description|
| -------- | -------- |
| Promise<Array<string>> | Promise used to return the configuration level directory list.|

**Example**
  ```js
  configPolicy.getCfgDirList().then(value => {
      console.log("value is " + value);
  }).catch(error => {
      console.log("getCfgDirList promise " + error);
  });
  ```