Developing a Custom Authorizer

Creating a Function Backend for Frontend Authentication

Develop a custom authentication function with a custom backend for access authentication.

1. Log in to the ROMA Connect console. On the Instances page, click View Console next to a specific instance.
2. Create an integration application.
   1. In the navigation pane on the left, choose Integration Applications. In the upper right corner of the page, click Create Integration Application.
   2. In the dialog box displayed, set Name and click OK.
3. In the navigation pane on the left, choose API Connect > Custom Backends. On the Backends tab, click Create Backend.
4. On the Create Backend page, set backend parameters and click Create.
   Figure 1 Custom backend configuration
   

   Table 1 Backend configuration

   Parameter	Description
   Name	Backend name.
   Integration Application	Select the integration application created in 2.
   Backend Request Method	The backend request method must be POST.
   Backend Request Path	Enter the request path of the backend, for example, /getUserInfo/userId.
   Backend Security Authentication	Backend authentication mode. Select None.
   Description	Enter a description of the backend.
   Advanced Settings	Retain the default settings in the Advanced Settings area.

   After the backend is created, the online IDE of the backend is automatically displayed. The backend type is data backend by default.

5. Develop a custom authentication function.

   In the upper left corner of the online IDE, choose File > New Function Backend > Frontend Custom Authentication Example. In the dialog box displayed, click OK, and then compile a function script for security authentication.

   Modify the authentication parameter name and value in the example. In this practice, the authentication parameter is header x-auth of the API request. When the value of x-auth is user1:xxxx, the authentication is successful.

   function execute(data) {
     data = JSON.parse(data)
     body = data.body
     if (body["headers"]["x-auth"] === 'user1:xxxx') {
         result = {
             "status": "allow",
             "context": {
                 "user_name":"user1"
             }
         }
     }
     else {
         result = {
             "status": "deny",
             "context": {
                 "error_code":"1001",
                 "error_message":"incorrect token input"
             }
         }
     }
     return result
   }

6. After editing the function, click Save in the upper right corner of the page to save the backend configuration.
7. Click Deploy in the upper right corner of the page. In the dialog box displayed, click Yes to deploy the function backend.

Creating a Frontend Custom Authorizer

1. In the navigation pane on the left, choose API Connect > API Policies. On the Custom Authorizers tab, click Create Custom Authorizer.
2. On the page displayed, configure custom authorization.
   Figure 2 Custom authorizer configuration
   

   Table 2 Parameters for creating a frontend custom authorizer

   Parameter	Description
   Name	Custom authorizer name.
   Integration Application	Select the integration application created in 2.
   Type	Select Frontend.
   Function URN	Select the Function backend created in Creating a Function Backend for Frontend Authentication.
   Max. Cache Age (s)	Retain the default settings.
   Identity Sources	Retain the default settings.
   Send Request Body	Retain the default settings.
   User Data	Retain the default settings.

3. Click OK.