Function Compute:Configure and use an HTTP trigger

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 parameters to create a function based on your business requirements.

   The following table describes the parameters that you must configure. Retain default values for other parameters. For more information, see Create a function.

   Parameter	Description
   Basic Settings
   Function Name	Specify the name of the function.
   Handler Type	Select HTTP Handler.
   (Optional) Trigger Configurations
   Name	Specify the name of the trigger.
   Request Method	Specify HTTP methods that can be used to trigger 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 default public domain name is available for the trigger. In this case, the access denied due to function internet URL is disable error message is returned if you use a public domain name to invoke the function. However, if you use a custom domain name, the function can be invoked as expected.
   Authentication Method	The method that is used to authenticate HTTP requests. Valid values: No Authentication: Function Compute does not authenticate HTTP requests and supports anonymous access to the function. All users can invoke the function by using HTTP requests. Signature Authentication: Identity authentication is required for HTTP requests. For more information about the sample code for signature authentication, see Signature authentication. JWT Authentication: HTTP requests must be authenticated by using a JSON Web Token (JWT). For more information, see Configure JWT authentication for an HTTP trigger.

   You can modify the configurations of the created HTTP trigger based on your business requirements. For example, you can modify the following parameters of the trigger: Version or Alias, Request Method, Disable Internet URL, and Authentication Method.

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 by using a browser

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

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

  Subdomain format:

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

  Sample code:

  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. If you use the assigned subdomain as the URL of the HTTP trigger to test the function, it can prevent 404 errors and the coupling of service names of Function Compute in the function code. This can improve the portability of the code. For more information about how to handle 404 errors, 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]            

  Sample code:

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

  Parameter description:

  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 Resource Access Management (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 ID of the region where Function Compute resides.
  version	The Function Compute API version.
  serviceName	The service name.
  functionName	The function name.
  action	The custom request path.
  queries	The query parameter.

Method 3: Use cURL to test the function

• Synchronous invocations

  Run the following command. After the command is executed, the result is returned.

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

• Asynchronous invocations

  Run the following command. The command output indicates whether Function Compute receives the asynchronous invocation request. If the 202 status code is returned, the asynchronous invocation request succeeds. If another status code is returned, an error occurs during the asynchronous invocation. For more information about status codes, see the Troubleshooting.

  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. Anyone can send an HTTP request to call an HTTP function. To prevent waste of resources and security risks caused by anonymous access, 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 HTTP function that you want to manage. On the function details page, click the Triggers tab, and then edit the HTTP trigger. In the dialog box that appears, set Authentication to Yes.

2. Log on to the API Gateway console and switch to the region in which the HTTP function resides.

3. Create a group. For more information, see the Create an API group section of the "Create an API with a backend service of the HTTP type" topic.

4. Resolve your domain name to the second-level domain name provided by API Gateway by using Canonical Name (CNAME). For more information, see Add a CNAME record.

5. Create an API.

   The following items describe how to configure the major 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. In subsequent operations, plug-ins are used for authentication.

   • Request Path: Enter the root directory / and select Match All Subpaths.

   • HTTP Method: Select ANY.

   • Request Mode: Select Pass-through.

   • Backend Service Type: Select Function Compute.

   • Function Type: Select HTTP Function.

   • Trigger Path: Select the internal endpoint of an HTTP function in Function Compute.

   • ContentType: Select Pass-through Client Content-type Header.

6. Publish the API. Find the API that you created, click Publish in the Actions column, select the online environment, and then click Publish.

7. Create a plug-in whose type is Backend Signature. Set key and value to the AccessKey ID and AccessKey secret of your Alibaba Cloud account. Then bind the plug-in to the API that you created. For more information, see Overview.

Troubleshooting

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.

• You can 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:

  • HTTP handlers in Node.js runtimes

  • HTTP handlers in Python runtimes

  • HTTP handlers in PHP runtimes

  • HTTP handlers in Java runtimes

  • HTTP handlers in C# runtimes

  • HTTP handlers in custom runtimes

  • HTTP handlers in Custom Container runtimes

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

Troubleshooting

If the issue persists, join the DingTalk user group (ID: 11721331) and contact Function Compute technical support.

More information

To modify or delete an existing trigger, see Manage triggers.