Post-user registration hook to add user_id to app_metadata

readme.md

How to set up

1. Go to Clients -> Create New -> and choose Non-Interactive to create a non-interactive client.
2. Go to APIs -> Auth0 Management API -> Non Interactive Clients
3. Authorize the newly created client. Also, check the update:users scope and click 'Update'.
4. Go to Hooks page and create a new post-registration hook with the contents in post-reg-hook.js file. Please make sure to change tenant_url in line 4 to your Auth0 domain.
5. In the hook editor, click on the wrench icon on top-left -> Secrets. Create two new secrets named client_id and client_secret and add the client ID and secret of the client you created in the first step.

Now, when a user signs up, their app_metadata will include an id attribute that contains the user_id.

post-reg-hook.js

module.exports = function (user, context, cb) {
  var request = require('[email protected]');

  var tenant_url = 'https://example.au.auth0.com';  // Change this to your Auth0 domain

  request.post({
    url: tenant_url + '/oauth/token',
    json: { 'client_id': context.webtask.secrets.client_id, 'client_secret': context.webtask.secrets.client_secret, 'audience':tenant_url+'/api/v2/', 'grant_type':'client_credentials'}
  }, function(err, response, body) {
    if (err) {
      console.log(err);
      return cb();
    }
    
    var token = body.access_token;
    var url = tenant_url + '/api/v2/users/auth0|' + user.id;
    request.patch({
      url: url,
      headers: {
        Authorization: 'Bearer ' + token
      },
      json: { 'app_metadata': { 'id': 'auth0|' + user.id } }
    }, function(err, response, body) {
      if (response && response.statusCode >= 400) {
        console.log(response.statusMessage);
      }
      cb();
    });
  });
};