Network Management Development

What are the data formats supported by extraData in an HTTP request? (API 9)

Solution

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 in the response to an HTTP request? (API 9)

Symptom

Error code 28 is reported after an HTTP request is initiated.

Solution

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

Common HTTP Response Codes and Curl Error Codes

What does error code 6 mean in the response to an HTTP request? (API 9)

Symptom

Error code 6 is reported after an HTTP request is initiated.

Solution

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

For more common error codes, see Common HTTP Response Codes and Curl Error Codes.

How are parameters passed to queryParams of the POST request initiated by @ohos/axios? (API 9)

Symptom

How are parameters passed to queryParams when the third-party component @ohos/axios initiates a POST request?

Solution

  • Method 1: Have the axios.post API receive only one parameter. The Url.URLSearchParams parameter needs to be converted into a string and appended to the end of the URL.

    let params:Url.URLSearchParams = new Url.URLSearchParams()
params.append('ctl', 'sug')
params.append('query', 'wangjunkai')
params.append('cfrom', '1099a')
axios.post('http://10.100.195.234:3000/save?' + params.toString()).then(res => {
  this.message = "request result: " + JSON.stringify(res.data);
}).catch(err => {
  this.message = "request error: " + err.message;
})

  • Method 2: Have the axios API receive only one config object. The request parameters are written in params of the config object.

    axios({
  url: 'http://10.100.195.234:3000/save',
  method: 'post',
  params: {
  ctl: 'sug',
  query: 'wangjunkai',
  cfrom: '1099a'
  }
}).then(res => {
  this.message = "request result: " + JSON.stringify(res.data);
}).catch(err => {
  this.message = "request error: " + err.message;
})

What should I do if no data is returned after connection.getNetCapabilities(mNetHandle) is called? (API 9)

Symptom

No data is returned after connection.getNetCapabilities() is called. What should I do?

Possible Cause

This problem is due to incorrect pointing of the this object. You are expected to use (err,data)=>{} instead of function(err,data) to access the callback function to obtain the return result. The reason is that the function declared by function has its own this object and therefore cannot point to the globalThis object.

Solution

Change function(err,data) to (err,data) for the second parameter of getNetCapabilities.

How HTTP Requests Are Transmitted in JSON Format (API 9)

Solution

In the HTTP message header, Content-Type is used to indicate the media type information. It tells the server how to process the requested data and tells the client (usually a browser) how to parse the response data, for example, displaying an image, parsing HTML, or displaying only the text.

To transmit data in HTTP requests in JSON format, set Content-Type to application/json.

this.options = {
  method:  http.RequestMethod.GET,
  extraData: this.extraData,
  header: { 'Content-Type': 'application/json' },
  readTimeout: 50000,
  connectTimeout: 50000
}

How do I upload photos taken by a camera to the server? (API 9)

Symptom

After an application calls the camera to take a photo, how do I upload the photo to the server?

Solution

After the application is started and the permission is obtained, have the system access the remote server and transfer the locally saved photos to the remote server through the upload API.

Reference

Upload and Download

What should I do if calling connection.hasDefaultNet() fails even when the network is normal? (API 9)

Symptom

The network connection is normal, and web pages can be opened properly on the browser. However, calling the hasDefaultNet fails, and the callback function returns an error.

Solution

Declare the ohos.permission.GET_NETWORK_INFO permission when calling connection.hasDefaultNet.

For details, see Applying for Permissions.

What does netId mean in the netHandle object returned by connection.getDefaultNet? (API 9)

Symptom

What are the meanings of the values of netId, such as 0 and 100?

Solution

If the value of netId is 0, no network connection is available. In such a case, check and rectify network faults. If the value is greater than or equal to 100, the network connection is normal.

How do I use HTTP requests to obtain data from the network? (API 9)

Solution

Use the @ohos.net.http module to initiate an HTTP request.

  1. Import the http module and create an HTTP request.

  2. Set the request URL and parameters and initiate the HTTP request.

  3. Obtain the response and parse the data.

Reference

HTTP Data Request

How do I encapsulate network requests by using JavaScript? (API 9)

Solution

The JavaScript development mode is supported. You can directly use JavaScript to encapsulate network requests. For details, see Network Connection.

How do I write network requests when developing a JavaScript-based application for smart watches? (API 9)

Solution

The JavaScript development mode is supported. You can directly use JavaScript to encapsulate network requests. For details, see Network Connection.

Why does an application fail to start after the ohos.permission.NOTIFICATION_CONTROLLER permission is declared? (API 9)

Symptom

When an application is started, the following error message is reported w: error: install failed due to grant request permissions failed.

Solution

The ohos.permission.NOTIFICATION_CONTROLLER permission is a system core permission and is not available for third-party applications.

What should I do if an error is reported when wifi.getIpInfo().ipAddress is used in the Wi-Fi module? (API 9)

Symptom

When wifi.getIpInfo().ipAddress is used in the Wi-Fi module, the following error message is reported: Error: assertion (wifiDevicePtr != nullptr) failed: Wifi device instance is null.

Solution

This problem is due to insufficient permissions. Check whether you have applied for the required permissions. For details, see Permission Management.