¶ Pipeline function development guide

¶ Pipeline function type

Currently Authing supports three types of Pipeline functions:

Name	Description
Pre-Register Pipeline	The pipeline before registration will be triggered every time the user officially enters the registration logic. Developers can use this to implement functions such as the whitelist of registered mailboxes and the whitelist of registered IP.
Post-Register Pipeline	The registered pipeline will be triggered every time the user completes the registration logic（it has been saved to the database at this time），Developers can use this to implement functions such as writing custom metadata to the database and new user registration webhook notification.
Post-Authentication Pipeline	The authenticated pipeline will be triggered every time the user completes the authentication. Developers can use this to implement functions such as adding custom fields to the token.
Pre-OIDCTokenIssued Pipeline	Triggered before the OIDC application code is exchanged for the token. Developers can use this to implement functions such as writing custom fields to the idToken. For details of the code-to-token part of the OIDC authentication process, please check：Using OIDC Authorization

¶ Function definition

Pipeline function definition：

async function pipe(user, context, callback)

Parameter Description：

¶ callback function

Definition：

function callback(error, user, context)

Description：

1. The first parameter of the callback function represents the error that the developer wants to pass to the end user. If it is not null, the entire authentication process will be interrupted and the error will be returned directly to the front end.
2. 2. If the first parameter is null, be sure to pass the latest user and context to the callback function, otherwise the subsequent pipeline function will not work properly.

¶ Setting up asynchronous execution

The pipeline function set to asynchronous execution（ asynchronous non-language level ）will not block the execution of the registration, login, and OIDC processes. The parameters passed in the callback function have no effect on the subsequent processes. It is suitable for asynchronous notification scenarios, such as social media group notification, trigger external system statistics, etc.

As shown in the figure below, checking this box means to let the pipeline function execute asynchronously:

¶ Pipeline function example

We implement a Pre-Register Pipeline for the whitelist of registered mailbox suffixes here.

async function pipe(context, callback) {
  const email = context.data.userInfo.email;
  // 非邮箱注册方式, 跳过此 pipe 函数
  if (!email) {
    return callback(null, context);
  }

  // 如果域名邮箱不是 example.com, 返回 Access denied. 错误给终端。
  if (!email.endsWith("@example.com")) {
    return callback(new Error("Access denied."));
  }
  return callback(null, context);
}

Briefly explain the code here:

• Lines 2-6 determine whether email is included in the request parameters, and if so, it means the email registration method. If not, skip the pipe function directly, and call callback with null and context parameters（don’t forget this parameter!）. If you just want to register by email, this step is okay if there is no email to return an error.
• Lines 8-10 determine whether the domain name of the mailbox isexample.com. If the callback function is not called, the first parameter is new Error('Access Denied.').
• On line 11, call return callback(null, context), and then enter the next pipe function, if there have the next function.