Function Compute (2.0):HTTP handler

HTTP handler signature

The following sample code provides an example on the signature of an HTTP handler in a Node.js runtime environment. You need to only implement one function to respond to HTTP requests.

exports.handler = (req, resp, context) => {
    console.log("receive body: ", req.body.toString());
    resp.setHeader("Content-Type", "text/plain");
    resp.send('<h1>Hello, world!</h1>');
}     

HTTP request struct

HTTP response struct

Limits

• Request limits

  If a request exceeds one of the following limits, the system returns status code 400 and error InvalidArgument.

  Field	Description	HTTP status code	Error code
  headers	The total size of the keys and values in the request headers cannot exceed 8 KB.	400	InvalidArgument
  path	The total size of the request path and query parameters cannot exceed 4 KB.
  body	The total size of the body of a synchronous invocation request cannot exceed 32 MB. The total size of the body of an asynchronous invocation request cannot exceed 128 KB.

• Response limits

  If a response exceeds one of the following limits, the system returns status code 502 and error BadResponse.

  Field	Description	HTTP status code	Error code
  headers	The total size of the keys and values in the response headers cannot exceed 8 KB.	502	BadResponse

Example: Obtain the details of the HTTP request and return the body

Sample code

module.exports.handler = function (request, response, context) {
    // get request header
    var reqHeader = request.headers
    var headerStr = ' '
    for (var key in reqHeader) {
        headerStr += key + ':' + reqHeader[key] + '  '
    };

    // get request info
    var url = request.url
    var path = request.path
    var queries = request.queries
    var queryStr = ''
    for (var param in queries) {
        queryStr += param + "=" + queries[param] + '  '
    };
    var method = request.method
    var clientIP = request.clientIP
    var body = request.body
    var respBody = new Buffer('requestHeader:' + headerStr + '\n' + 'url: ' + url + '\n' + 'path: ' + path + '\n' + 'queries: ' + queryStr + '\n' + 'method: ' + method + '\n' + 'clientIP: ' + clientIP + '\n' + 'body: ' + body + '\n')
    response.setStatusCode(200)
    response.setHeader('content-type', 'application/json')
    response.send(respBody)
};

Before you start

Create a service

Procedure

1. Log on to the Function Compute console. In the left-side navigation pane, click Services & Functions.

2. In the top navigation bar, select a region. On the Services page, click the desired service.

3. On the Functions page, click Create Function.

   Create an HTTP function whose runtime environment is Node.js 14.x. For more information, see Create a function.

4. On the function details page, click the Code tab, enter the preceding sample code in the code editor, and then click Deploy.

   Note

   In the preceding sample code, the handler of the function is the handler method in index.js. If you specify a different handler, use the actual file and method. For more information, see Lifecycle hooks for function instances.

5. On the Code tab, click the icon next to Test Function and select Configure Test Parameters from the drop-down list.

6. In the Configure Test Parameters panel, click Create New Test Event or Modify Existing Test Event, set the following parameters, and then click OK.

   • Request Name: Enter a custom request name.

   • Request Method: Select POST.

   • Request Path: Enter ?foo=bar.

   • Request Body: Enter hello,fc in the code editor.

7. Click Test Function.

   After the function is executed, the information such as the client IP address is contained in the returned result.