Function Compute:Configure an HTTP trigger that invokes a function with HTTP requests

Step 1: Create a trigger

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.
4. On the Create Function page, select Use Built-in Runtime and configure the parameters of the function.
   The following table describes the parameters that you must configure. Retain the default values for other parameters. For more information, see Create a function.

   Parameter	Description
   Basic Settings
   Function Name	Specify the name of the function.
   Request Type	Select HTTP Requests.
   Trigger Configurations (optional)
   Name	Specify the name of the trigger.
   Disable Internet URL	By default, this parameter is set to No and public domain names are allowed to access the trigger. If you select Yes, no public domain name is provided for the created HTTP trigger. In this case, the error access denied due to function internet URL is disable is reported if you use the public domain name to invoke the function. The access is not affected if the domain name is customized.
   Authentication	By default, this parameter is set to No, and the system does not authenticate the HTTP requests and supports anonymous access to the trigger. If you select Yes, the system authenticates the HTTP requests and does not support anonymous access. This enhances the security.
   Request Method	Specify the methods that can be used to trigger the HTTP trigger.

   You can modify the settings of the created HTTP trigger based on your business requirements, including the Disable Internet URL, Authentication, and Request Method parameters.

Step 2: Write and deploy code

After the HTTP trigger is created, you can write the code for the function.

var getRawBody = require('raw-body')
module.exports.handler = function (request, response, context) {
    // get request info
    getRawBody(request, function (err, data) {
        var params = {
            path: request.path,
            queries: request.queries,
            headers: request.headers,
            method: request.method,
            body: data,
            url: request.url,
            clientIP: request.clientIP,
        }
        // you can deal with your own logic here
        // set response
        var respBody = new Buffer.from(JSON.stringify(params));
        // var respBody = new Buffer( )
        response.setStatusCode(200)
        response.setHeader('content-type', 'application/json')
        response.send(respBody)
    })
};

# -*- coding: utf-8 -*-
import json
HELLO_WORLD = b"Hello world!\n"
def handler(environ, start_response):
    request_uri = environ['fc.request_uri']
    response_body = {
      'uri':environ['fc.request_uri'],
      'method':environ['REQUEST_METHOD']
    }
    # do something here
    status = '200 OK'
    response_headers = [('Content-type', 'text/json')]
    start_response(status, response_headers)
    # Python2
    return [json.dumps(response_body)]
    # Python3 tips: When using Python3, the str and bytes types cannot be mixed.
    # Use str.encode() to go from str to bytes
    # return [json.dumps(response_body).encode()]

<?php
use RingCentral\Psr7\Response;
function handler($request, $context): Response{
    /*
    $body       = $request->getBody()->getContents();
    $queries    = $request->getQueryParams();
    $method     = $request->getMethod();
    $headers    = $request->getHeaders();
    $path       = $request->getAttribute("path");
    $requestURI = $request->getAttribute("requestURI");
    $clientIP   = $request->getAttribute("clientIP");
    */
    return new Response(
        200,
        array(
            "custom_header1" => "v1",
            "custom_header2" => ["v2", "v3"],
        ),
        "hello world"
    );
}

Step 3: Test the function

Method 1: Test the function in the Function Compute console

Method 2: Test the function in a browser

You can use one of the following methods to obtain the URL of an HTTP trigger.

• For a new HTTP trigger, we recommend that you use the subdomain that is assigned by Function Compute to the HTTP trigger as the HTTP trigger URL.

  Subdomain format:

  <subdomain>.<region_id>.fcapp.run/[action?queries] 

  Example:

  funcname-svcname-khljsjksld.cn-shanghai.fcapp.run/action?hello=world

  Note You can also assemble a URL for an existing HTTP trigger based on the assembly rule. We recommend that you test the function by using the HTTP trigger URL that contains the subdomain assigned by Function Compute to the new HTTP trigger in Function Compute. This helps prevent the 404 error and the coupling of Function Compute service names and function names in the code. This also helps improve the portability of the code. For more information about the 404 error, see What do I do if a 404 error occurs when I use a browser or the cURL tool to access a function?.
• For an existing HTTP trigger, you can generate an HTTP trigger URL based on the assembly rule.

  Assembly rule:

  <account_id>.<region_id>.fc.aliyuncs.com/<version>/proxy/<serviceName>/<functionName>/[action?queries]            

  Example:

  164901546557****.cn-shanghai.fc.aliyuncs.com/2016-08-15/proxy/serviceName/functionName/action?hello=world           

  The following table describes the parameters.

  Parameter	Description
  account_id	The ID of the Alibaba Cloud account. You can obtain the ID of your Alibaba Cloud account on the Security Settings page in the Alibaba Cloud Management Console. If you log on as a RAM user, move the pointer over your profile picture in the upper-right corner of the console to obtain the ID of your Alibaba Cloud account.
  region_id	The region where the Function Compute service resides.
  version	The version of the Function Compute API.
  serviceName	The name of the service.
  functionName	The name of the function.
  action	The custom request path.
  queries	The query parameter.

Method 3: Use cURL to test the function

• Synchronous invocation
  Run the following command. After the command is executed, the result is returned.

  curl -v https://http-***.cn-shenzhen.fcapp.run/$path

• Asynchronous invocation
  Run the following command. After the command is executed, the result that is returned indicates whether Function Compute receives the asynchronous invocation request. If the status code 202 is returned, the asynchronous invocation request is successful. If another status code is returned, an exception occurs during the asynchronous invocation. For more information about error codes, see Troubleshooting in FAQ.

  curl -v -H "X-Fc-Invocation-Type: Async" https://http-***.cn-shenzhen.fcapp.run/$path

(Optional) Use API Gateway to protect HTTP functions

By default, Function Compute does not authenticate HTTP requests and supports anonymous access to HTTP functions. This means that anyone can send an HTTP request to invoke your function. To prevent waste of resources and security risks caused by the access of unauthorized users, you can connect HTTP functions to API Gateway while you enable identity authentication. You can use the IP-based access control plug-ins, JWT authentication plug-ins, or basic authentication plug-ins of API Gateway to protect your HTTP functions.

1. In the Function Compute console, find the desired HTTP function. On the function details page, click the Triggers tab. Then, edit the HTTP trigger and select Yes for Authentication.
2. Log on to the API Gateway console and switch to the region where the HTTP function resides.
3. Create a group. For more information, see Create a group.
4. Resolve your domain name to the second-level domain name provided by API Gateway by using CNAME. For more information, see Add a CNAME record for a domain name.
5. Create an API.
   The following items describe how to configure the main parameters. Retain the default values or configure custom values for other parameters based on your business requirements. For more information, see Create an API.

   • Security Authentication: Select No Authentication. Plug-ins will be used for authentication.
   • Request Path: Enter the root directory /and select Match All Subpaths.
   • HTTP Method: Select ANY.
   • Request Mode: Select Passthrough.
   • Backend Service Type: Select Function Compute.
   • Function Type: Select HTTP Function.
   • Trigger Path: Enter the internal endpoint of the Function Compute HTTP function.
   • ContentType: Select Pass-through Client Content-type Header.
6. Publish the API. Click Publish in the Actions column of the created API, select the online environment, and then click Publish.
7. Create a plug-in whose type is Backend Service Signature. Configure key and value as the AccessKey ID and AccessKey secret of your Alibaba Cloud account. Then bind the API that you created. For more information, see Overview.

FAQ

Why am I unable to execute an HTTP function?

• For a new trigger, the cache requires approximately 10 seconds to update. You can try again later.
• Check whether the handler that you specified for your function is valid. The handler for an HTTP function is different from the handler for a regular function. For more information about HTTP functions in different languages, see the following topics:
  • Node.js HTTP functions
  • Python HTTP functions
  • PHP HTTP functions
  • Java HTTP functions
  • HTTP handlers
  • HTTP functions in custom runtimes
  • HTTP functions in custom containers

Why am I unable to terminate the execution of a function?

Troubleshooting

If the issue persists, Join the DingTalk group 11721331 to communicate instantly with Function Compute engineers..

References

To modify or delete an existing trigger, see Trigger management.