portainer/app/extensions/registry-management/rest/gitlab.js

import gitlabResponseGetLink from './transform/gitlabResponseGetLink'

angular.module('portainer.extensions.registrymanagement')
.factory('Gitlab', ['$resource', 'API_ENDPOINT_REGISTRIES',
function GitlabFactory($resource, API_ENDPOINT_REGISTRIES) {
  'use strict';
  return function(env) {
    const headers = {};
    if (env) {
      headers['Private-Token'] = env.token;
      headers['X-Gitlab-Domain'] = env.url
    }

    const baseUrl = API_ENDPOINT_REGISTRIES + '/:id/proxies/gitlab/api/v4/projects';

    return $resource(baseUrl, {id:'@id'},
    {
      projects: {
        method: 'GET',
        params: { membership: 'true' },
        transformResponse: gitlabResponseGetLink,
        headers: headers
      },
      repositories :{
        method: 'GET',
        url: baseUrl + '/:projectId/registry/repositories',
        params: { tags: true },
        headers: headers,
        transformResponse: gitlabResponseGetLink
      }
    });
  };
}]);