Add sorting options for /users API (admin only)

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

changelogs/unreleased/42669-allow-order_by-users-in-gitlab-api.yml

+---
+title: Add sorting options for /users API (admin only)
+merge_request: 16945
+author:
+type: added

doc/api/users.md

@@ -51,6 +51,11 @@ GET /users?blocked=true
 GET /users
 ```
+| Attribute | Type | Required | Description |
+| --------- | ---- | -------- | ----------- |
+| `order_by` | string | no | Return projects ordered by `id`, `name`, `username`, `created_at`, or `updated_at` fields. Default is `id` |
+| `sort` | string | no | Return projects sorted in `asc` or `desc` order. Default is `desc` |
+
 ```json
 [
   {

lib/api/users.rb

@@ -18,6 +18,14 @@ module API
           User.find_by(id: id) || not_found!('User')
         end
+        def reorder_users(users)
+          if params[:order_by] && params[:sort]
+            users.reorder(params[:order_by] => params[:sort])
+          else
+            users
+          end
+        end
+
         params :optional_attributes do
           optional :skype, type: String, desc: 'The Skype username'
           optional :linkedin, type: String, desc: 'The LinkedIn username'
@@ -35,6 +43,13 @@ module API
           optional :avatar, type: File, desc: 'Avatar image for user'
           all_or_none_of :extern_uid, :provider
         end
+
+        params :sort_params do
+          optional :order_by, type: String, values: %w[id name username created_at updated_at],
+                              default: 'id', desc: 'Return users ordered by a field'
+          optional :sort, type: String, values: %w[asc desc], default: 'desc',
+                          desc: 'Return users sorted in ascending and descending order'
+        end
       end
       desc 'Get the list of users' do
@@ -53,16 +68,18 @@ module API
         optional :created_before, type: DateTime, desc: 'Return users created before the specified time'
         all_or_none_of :extern_uid, :provider
+        use :sort_params
         use :pagination
       end
       get do
         authenticated_as_admin! if params[:external].present? || (params[:extern_uid].present? && params[:provider].present?)
         unless current_user&.admin?
-          params.except!(:created_after, :created_before)
+          params.except!(:created_after, :created_before, :order_by, :sort)
         end
         users = UsersFinder.new(current_user, params).execute
+        users = reorder_users(users)
         authorized = can?(current_user, :read_users_list)

spec/requests/api/users_spec.rb

@@ -199,6 +199,24 @@ describe API::Users do
         expect(json_response.size).to eq(1)
         expect(json_response.first['username']).to eq(user.username)
       end
+
+      it 'returns the correct order when sorted by id' do
+        admin
+        user
+
+        get api('/users', admin), { order_by: 'id', sort: 'asc' }
+
+        expect(response).to match_response_schema('public_api/v4/user/admins')
+        expect(json_response.size).to eq(2)
+        expect(json_response.first['id']).to eq(admin.id)
+        expect(json_response.last['id']).to eq(user.id)
+      end
+
+      it 'returns 400 when provided incorrect sort params' do
+        get api('/users', admin), { order_by: 'magic', sort: 'asc' }
+
+        expect(response).to have_gitlab_http_status(400)
+      end
     end
   end