## What are the data formats supported by extraData in an HTTP request?
Applicable to: OpenHarmony SDK 3.2.2.5, stage model of API version 9
**extraData** indicates additional data in an HTTP request. It varies depending on the HTTP request method.
- If the HTTP request uses a POST or PUT method, **extraData** serves as the content of the HTTP request.
- If the HTTP request uses a GET, OPTIONS, DELETE, TRACE, or CONNECT method, **extraData** serves as a supplement to the HTTP request parameters and will be added to the URL when the request is sent.
- If you pass in a string object, **extraData** contains the string encoded on your own.
## What does error code 28 mean for an HTTP request?
Applicable to: OpenHarmony SDK 3.2.2.5, stage model of API version 9
Error code 28 refers to **CURLE_OPERATION_TIMEDOUT**, which means a libcurl library operation timeout. For details, see any HTTP status code description available.
Reference: [Development Guide](https://gitee.com/openharmony/docs/blob/master/en/application-dev/reference/apis/js-apis-http.md#httpresponse) and [Curl Error Codes](https://curl.se/libcurl/c/libcurl-errors.html)
## What does error code 6 mean for the response of \@ohos.net.http.d.ts?
Applicable to: OpenHarmony SDK 3.2.3.5
Error code 6 indicates a failure to resolve the host in the address. You can ping the URL carried in the request to check whether the host is accessible.
Reference: [Development Guide](https://gitee.com/openharmony/docs/blob/master/en/application-dev/reference/apis/js-apis-http.md#httpresponse) and [Curl Error Codes](https://curl.se/libcurl/c/libcurl-errors.html)
- Disabling the privacy flag: hdc_std shell hilog -p off
- Increasing the log buffer to 200 MB: hdc_std shell hilog -G 200M
- Enabling the log function of the specific domain (that is, disabling the global log function): hdc_std shell hilog –b D –D 0xd0xxxxx
After performing the preceding operations, restart the DevEco Studio.
## Is HiLog or Console recommended for log printing? How do I set the domain if HiLog is used?
Applicable to: OpenHarmony SDK 3.2.2.5
[HiLog](https://gitee.com/openharmony/docs/blob/master/en/application-dev/reference/apis/js-apis-hilog.md) is recommended for an application to print logs. For details about domain setting, see [Development Guide](https://gitee.com/openharmony/docs/blob/master/en/application-dev/reference/apis/js-apis-hilog.md#hilogisloggable).
## What is the maximum length of a log record when HiLog is used? Is it configurable?
Applicable to: OpenHarmony SDK 3.2.2.5
The maximum length of a log record is 1,024 characters, and it is not changeable.
## What should I do if a HAP package cannot be opened after being installed on the development board using the IDE?
Applicable to: OpenHarmony SDK 3.2.5.3, stage model of API version 9
Check whether the SDK version is consistent with the system version on the development board. You are advised to use the SDK version and system version that are released on the same day.
## How do I upload files using an hdc command?
Applicable to: OpenHarmony SDK 3.2.2.5
Run the **hdc_std file send** command.
## How do I prevent the screen of the RK3568 development board from turning off?
Applicable to: OpenHarmony SDK 3.2.5.3, stage model of API version 9
Run the **hdc_std shell "power-shell setmode 602"** command.
## How do I start an ability using an hdc command?
Applicable to: OpenHarmony SDK 3.2.5.3, stage model of API version 9
Run the **hdc_std shell aa start -a AbilityName -b bundleName -m moduleName** command.
## What should do if the error message "npm ERR! code SELF_SIGNED_CERT_IN_CHAIN" is displayed?
Applicable to: OpenHarmony SDK 3.2.5.3, stage model of API version 9
1. Run **npm config set strict-ssl=false** on the DevEco Studio terminal.
2. Run the **npm install** on the DevEco Studio terminal.
## After manual updating of the DevEco Studio SDK, the error message "Cannot find module 'xxx\ets\x.x.x.x\build-tools\ets-loader\node_modules\webpack\bin\webpack.js'" is displayed during HAP building. What should I do?
Applicable to: OpenHarmony SDK 3.2.5.3, stage model of API version 9
1. Run **npm install** in the **ets\x.x.x.x\build-tools\ets-loader** directory of the SDK.
2. Run **npm install** in the **js\x.x.x.x\build-tools\ace-loader** directory of the SDK.
