Add REST API for creating an account (#9572)

* Add REST API for creating an account

The method is available to apps with a token obtained via the client
credentials grant. It creates a user and account records, as well as
an access token for the app that initiated the request. The user is
unconfirmed, and an e-mail is sent as usual.

The method returns the access token, which the app should save for
later. The REST API is not available to users with unconfirmed
accounts, so the app must be smart to wait for the user to click a
link in their e-mail inbox.

The method is rate-limited by IP to 5 requests per 30 minutes.

* Redirect users back to app from confirmation if they were created with an app

* Add tests

* Return 403 on the method if registrations are not open

* Require agreement param to be true in the API when creating an account

18 files changed, 171 insertions, 20 deletions

diff --git a/app/controllers/api/base_controller.rb b/app/controllers/api/base_controller.rb
index ac8de5fc0f4..2bf8e82db86 100644
--- a/app/controllers/api/base_controller.rb
+++ b/app/controllers/api/base_controller.rb
@@ -68,7 +68,7 @@ class Api::BaseController < ApplicationController
   end
 
   def require_user!
-    if current_user && !current_user.disabled?
+    if current_user && !current_user.disabled? && current_user.confirmed?
       set_user_activity
     elsif current_user
       render json: { error: 'Your login is currently disabled' }, status: 403
diff --git a/app/controllers/api/v1/accounts_controller.rb b/app/controllers/api/v1/accounts_controller.rb
index f711c467675..6e4084c4e33 100644
--- a/app/controllers/api/v1/accounts_controller.rb
+++ b/app/controllers/api/v1/accounts_controller.rb
@@ -1,14 +1,16 @@
 # frozen_string_literal: true
 
 class Api::V1::AccountsController < Api::BaseController
-  before_action -> { authorize_if_got_token! :read, :'read:accounts' }, except: [:follow, :unfollow, :block, :unblock, :mute, :unmute]
+  before_action -> { authorize_if_got_token! :read, :'read:accounts' }, except: [:create, :follow, :unfollow, :block, :unblock, :mute, :unmute]
   before_action -> { doorkeeper_authorize! :follow, :'write:follows' }, only: [:follow, :unfollow]
   before_action -> { doorkeeper_authorize! :follow, :'write:mutes' }, only: [:mute, :unmute]
   before_action -> { doorkeeper_authorize! :follow, :'write:blocks' }, only: [:block, :unblock]
+  before_action -> { doorkeeper_authorize! :write, :'write:accounts' }, only: [:create]
 
-  before_action :require_user!, except: [:show]
-  before_action :set_account
+  before_action :require_user!, except: [:show, :create]
+  before_action :set_account, except: [:create]
   before_action :check_account_suspension, only: [:show]
+  before_action :check_enabled_registrations, only: [:create]
 
   respond_to :json
 
@@ -16,6 +18,16 @@ class Api::V1::AccountsController < Api::BaseController
     render json: @account, serializer: REST::AccountSerializer
   end
 
+  def create
+    token    = AppSignUpService.new.call(doorkeeper_token.application, account_params)
+    response = Doorkeeper::OAuth::TokenResponse.new(token)
+
+    headers.merge!(response.headers)
+
+    self.response_body = Oj.dump(response.body)
+    self.status        = response.status
+  end
+
   def follow
     FollowService.new.call(current_user.account, @account, reblogs: truthy_param?(:reblogs))
 
@@ -62,4 +74,12 @@ class Api::V1::AccountsController < Api::BaseController
   def check_account_suspension
     gone if @account.suspended?
   end
+
+  def account_params
+    params.permit(:username, :email, :password, :agreement)
+  end
+
+  def check_enabled_registrations
+    forbidden if single_user_mode? || !Setting.open_registrations
+  end
 end
diff --git a/app/controllers/auth/confirmations_controller.rb b/app/controllers/auth/confirmations_controller.rb
index 7af9cbe81db..c28c7471c0d 100644
--- a/app/controllers/auth/confirmations_controller.rb
+++ b/app/controllers/auth/confirmations_controller.rb
@@ -6,9 +6,9 @@ class Auth::ConfirmationsController < Devise::ConfirmationsController
   before_action :set_body_classes
   before_action :set_user, only: [:finish_signup]
 
-  # GET/PATCH /users/:id/finish_signup
   def finish_signup
     return unless request.patch? && params[:user]
+
     if @user.update(user_params)
       @user.skip_reconfirmation!
       bypass_sign_in(@user)
@@ -31,4 +31,12 @@ class Auth::ConfirmationsController < Devise::ConfirmationsController
   def user_params
     params.require(:user).permit(:email)
   end
+
+  def after_confirmation_path_for(_resource_name, user)
+    if user.created_by_application && truthy_param?(:redirect_to_app)
+      user.created_by_application.redirect_uri
+    else
+      super
+    end
+  end
 end
diff --git a/app/controllers/auth/registrations_controller.rb b/app/controllers/auth/registrations_controller.rb
index 088832be3c5..f2a832542fe 100644
--- a/app/controllers/auth/registrations_controller.rb
+++ b/app/controllers/auth/registrations_controller.rb
@@ -26,6 +26,7 @@ class Auth::RegistrationsController < Devise::RegistrationsController
 
     resource.locale      = I18n.locale
     resource.invite_code = params[:invite_code] if resource.invite_code.blank?
+    resource.agreement   = true
 
     resource.build_account if resource.account.nil?
   end
diff --git a/app/models/user.rb b/app/models/user.rb
index 44e0d11139c..77e48ed4b9d 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -36,6 +36,7 @@
 #  invite_id                 :bigint(8)
 #  remember_token            :string
 #  chosen_languages          :string           is an Array
+#  created_by_application_id :bigint(8)
 #
 
 class User < ApplicationRecord
@@ -66,6 +67,7 @@ class User < ApplicationRecord
 
   belongs_to :account, inverse_of: :user
   belongs_to :invite, counter_cache: :uses, optional: true
+  belongs_to :created_by_application, class_name: 'Doorkeeper::Application', optional: true
   accepts_nested_attributes_for :account
 
   has_many :applications, class_name: 'Doorkeeper::Application', as: :owner
@@ -74,6 +76,7 @@ class User < ApplicationRecord
   validates :locale, inclusion: I18n.available_locales.map(&:to_s), if: :locale?
   validates_with BlacklistedEmailValidator, if: :email_changed?
   validates_with EmailMxValidator, if: :validate_email_dns?
+  validates :agreement, acceptance: { allow_nil: false, accept: [true, 'true', '1'] }, on: :create
 
   scope :recent, -> { order(id: :desc) }
   scope :admins, -> { where(admin: true) }
@@ -294,7 +297,7 @@ class User < ApplicationRecord
       end
 
     if resource.blank?
-      resource = new(email: attributes[:email])
+      resource = new(email: attributes[:email], agreement: true)
       if Devise.check_at_sign && !resource[:email].index('@')
         resource[:email] = Rpam2.getenv(resource.find_pam_service, attributes[:email], attributes[:password], 'email', false)
         resource[:email] = "#{attributes[:email]}@#{resource.find_pam_suffix}" unless resource[:email]
@@ -307,7 +310,7 @@ class User < ApplicationRecord
     resource = joins(:account).find_by(accounts: { username: attributes[Devise.ldap_uid.to_sym].first })
 
     if resource.blank?
-      resource = new(email: attributes[:mail].first, account_attributes: { username: attributes[Devise.ldap_uid.to_sym].first })
+      resource = new(email: attributes[:mail].first, agreement: true, account_attributes: { username: attributes[Devise.ldap_uid.to_sym].first })
       resource.ldap_setup(attributes)
     end
 
diff --git a/app/services/app_sign_up_service.rb b/app/services/app_sign_up_service.rb
new file mode 100644
index 00000000000..1878587e809
--- /dev/null
+++ b/app/services/app_sign_up_service.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class AppSignUpService < BaseService
+  def call(app, params)
+    return unless allowed_registrations?
+
+    user_params    = params.slice(:email, :password, :agreement)
+    account_params = params.slice(:username)
+    user           = User.create!(user_params.merge(created_by_application: app, password_confirmation: user_params[:password], account_attributes: account_params))
+
+    Doorkeeper::AccessToken.create!(application: app,
+                                    resource_owner_id: user.id,
+                                    scopes: app.scopes,
+                                    expires_in: Doorkeeper.configuration.access_token_expires_in,
+                                    use_refresh_token: Doorkeeper.configuration.refresh_token_enabled?)
+  end
+
+  private
+
+  def allowed_registrations?
+    Setting.open_registrations && !Rails.configuration.x.single_user_mode
+  end
+end
diff --git a/app/views/user_mailer/confirmation_instructions.html.haml b/app/views/user_mailer/confirmation_instructions.html.haml
index 1f088a16f4f..f75f7529a8f 100644
--- a/app/views/user_mailer/confirmation_instructions.html.haml
+++ b/app/views/user_mailer/confirmation_instructions.html.haml
@@ -55,8 +55,12 @@
                             %tbody
                               %tr
                                 %td.button-primary
-                                  = link_to confirmation_url(@resource, confirmation_token: @token) do
-                                    %span= t 'devise.mailer.confirmation_instructions.action'
+                                  - if @resource.created_by_application
+                                    = link_to confirmation_url(@resource, confirmation_token: @token, redirect_to_app: 'true') do
+                                      %span= t 'devise.mailer.confirmation_instructions.action_with_app', app: @resource.created_by_application.name
+                                  - else
+                                    = link_to confirmation_url(@resource, confirmation_token: @token) do
+                                      %span= t 'devise.mailer.confirmation_instructions.action'
 
 %table.email-table{ cellspacing: 0, cellpadding: 0 }
   %tbody
diff --git a/app/views/user_mailer/confirmation_instructions.text.erb b/app/views/user_mailer/confirmation_instructions.text.erb
index e01eecb27e2..65b4626c669 100644
--- a/app/views/user_mailer/confirmation_instructions.text.erb
+++ b/app/views/user_mailer/confirmation_instructions.text.erb
@@ -4,7 +4,7 @@
 
 <%= t 'devise.mailer.confirmation_instructions.explanation', host: site_hostname %>
 
-=> <%= confirmation_url(@resource, confirmation_token: @token) %>
+=> <%= confirmation_url(@resource, confirmation_token: @token, redirect_to_app: @resource.created_by_application ? 'true' : nil) %>
 
 <%= strip_tags(t('devise.mailer.confirmation_instructions.extra_html', terms_path: about_more_url, policy_path: terms_url)) %>
 
diff --git a/config/initializers/rack_attack.rb b/config/initializers/rack_attack.rb
index 8756b8fbf0e..35302e37b1b 100644
--- a/config/initializers/rack_attack.rb
+++ b/config/initializers/rack_attack.rb
@@ -57,6 +57,10 @@ class Rack::Attack
     req.authenticated_user_id if req.post? && req.path.start_with?('/api/v1/media')
   end
 
+  throttle('throttle_api_sign_up', limit: 5, period: 30.minutes) do |req|
+    req.ip if req.post? && req.path == '/api/v1/accounts'
+  end
+
   throttle('protected_paths', limit: 25, period: 5.minutes) do |req|
     req.ip if req.post? && req.path =~ PROTECTED_PATHS_REGEX
   end
diff --git a/config/locales/devise.en.yml b/config/locales/devise.en.yml
index 20938e47b64..bd0642b2516 100644
--- a/config/locales/devise.en.yml
+++ b/config/locales/devise.en.yml
@@ -18,6 +18,7 @@ en:
     mailer:
       confirmation_instructions:
         action: Verify email address
+        action_with_app: Confirm and return to %{app}
         explanation: You have created an account on %{host} with this email address. You are one click away from activating it. If this wasn't you, please ignore this email.
         extra_html: Please also check out <a href="%{terms_path}">the rules of the instance</a> and <a href="%{policy_path}">our terms of service</a>.
         subject: 'Mastodon: Confirmation instructions for %{instance}'
diff --git a/config/routes.rb b/config/routes.rb
index 7723a08af97..808bb5acd6c 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -336,7 +336,7 @@ Rails.application.routes.draw do
         resources :relationships, only: :index
       end
 
-      resources :accounts, only: [:show] do
+      resources :accounts, only: [:create, :show] do
         resources :statuses, only: :index, controller: 'accounts/statuses'
         resources :followers, only: :index, controller: 'accounts/follower_accounts'
         resources :following, only: :index, controller: 'accounts/following_accounts'
diff --git a/db/migrate/20181219235220_add_created_by_application_id_to_users.rb b/db/migrate/20181219235220_add_created_by_application_id_to_users.rb
new file mode 100644
index 00000000000..17ce900af30
--- /dev/null
+++ b/db/migrate/20181219235220_add_created_by_application_id_to_users.rb
@@ -0,0 +1,8 @@
+class AddCreatedByApplicationIdToUsers < ActiveRecord::Migration[5.2]
+  disable_ddl_transaction!
+
+  def change
+    add_reference :users, :created_by_application, foreign_key: { to_table: 'oauth_applications', on_delete: :nullify }, index: false
+    add_index :users, :created_by_application_id, algorithm: :concurrently
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 51a7b5e7498..e47960b1693 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2018_12_13_185533) do
+ActiveRecord::Schema.define(version: 2018_12_19_235220) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -637,8 +637,10 @@ ActiveRecord::Schema.define(version: 2018_12_13_185533) do
     t.bigint "invite_id"
     t.string "remember_token"
     t.string "chosen_languages", array: true
+    t.bigint "created_by_application_id"
     t.index ["account_id"], name: "index_users_on_account_id"
     t.index ["confirmation_token"], name: "index_users_on_confirmation_token", unique: true
+    t.index ["created_by_application_id"], name: "index_users_on_created_by_application_id"
     t.index ["email"], name: "index_users_on_email", unique: true
     t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
   end
@@ -730,6 +732,7 @@ ActiveRecord::Schema.define(version: 2018_12_13_185533) do
   add_foreign_key "subscriptions", "accounts", name: "fk_9847d1cbb5", on_delete: :cascade
   add_foreign_key "users", "accounts", name: "fk_50500f500d", on_delete: :cascade
   add_foreign_key "users", "invites", on_delete: :nullify
+  add_foreign_key "users", "oauth_applications", column: "created_by_application_id", on_delete: :nullify
   add_foreign_key "web_push_subscriptions", "oauth_access_tokens", column: "access_token_id", on_delete: :cascade
   add_foreign_key "web_push_subscriptions", "users", on_delete: :cascade
   add_foreign_key "web_settings", "users", name: "fk_11910667b2", on_delete: :cascade
diff --git a/lib/mastodon/accounts_cli.rb b/lib/mastodon/accounts_cli.rb
index b219682232c..bbda244eade 100644
--- a/lib/mastodon/accounts_cli.rb
+++ b/lib/mastodon/accounts_cli.rb
@@ -73,7 +73,7 @@ module Mastodon
     def create(username)
       account  = Account.new(username: username)
       password = SecureRandom.hex
-      user     = User.new(email: options[:email], password: password, admin: options[:role] == 'admin', moderator: options[:role] == 'moderator', confirmed_at: Time.now.utc)
+      user     = User.new(email: options[:email], password: password, agreement: true, admin: options[:role] == 'admin', moderator: options[:role] == 'moderator', confirmed_at: options[:confirmed] ? Time.now.utc : nil)
 
       if options[:reattach]
         account = Account.find_local(username) || Account.new(username: username)
diff --git a/spec/controllers/api/v1/accounts_controller_spec.rb b/spec/controllers/api/v1/accounts_controller_spec.rb
index c506fb5f01a..f5f65c000e5 100644
--- a/spec/controllers/api/v1/accounts_controller_spec.rb
+++ b/spec/controllers/api/v1/accounts_controller_spec.rb
@@ -19,6 +19,40 @@ RSpec.describe Api::V1::AccountsController, type: :controller do
     end
   end
 
+  describe 'POST #create' do
+    let(:app) { Fabricate(:application) }
+    let(:token) { Doorkeeper::AccessToken.find_or_create_for(app, nil, 'read write', nil, false) }
+    let(:agreement) { nil }
+
+    before do
+      post :create, params: { username: 'test', password: '12345678', email: 'hello@world.tld', agreement: agreement }
+    end
+
+    context 'given truthy agreement' do
+      let(:agreement) { 'true' }
+
+      it 'returns http success' do
+        expect(response).to have_http_status(200)
+      end
+
+      it 'returns a new access token as JSON' do
+        expect(body_as_json[:access_token]).to_not be_blank
+      end
+
+      it 'creates a user' do
+        user = User.find_by(email: 'hello@world.tld')
+        expect(user).to_not be_nil
+        expect(user.created_by_application_id).to eq app.id
+      end
+    end
+
+    context 'given no agreement' do
+      it 'returns http unprocessable entity' do
+        expect(response).to have_http_status(422)
+      end
+    end
+  end
+
   describe 'GET #show' do
     let(:scopes) { 'read:accounts' }
 
diff --git a/spec/fabricators/user_fabricator.rb b/spec/fabricators/user_fabricator.rb
index 7dfbdb52d77..8f59565016d 100644
--- a/spec/fabricators/user_fabricator.rb
+++ b/spec/fabricators/user_fabricator.rb
@@ -3,4 +3,5 @@ Fabricator(:user) do
   email        { sequence(:email) { |i| "#{i}#{Faker::Internet.email}" } }
   password     "123456789"
   confirmed_at { Time.zone.now }
+  agreement    true
 end
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index c829195972e..856254ce4b6 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -106,19 +106,19 @@ RSpec.describe User, type: :model do
     end
 
     it 'should allow a non-blacklisted user to be created' do
-      user = User.new(email: 'foo@example.com', account: account, password: password)
+      user = User.new(email: 'foo@example.com', account: account, password: password, agreement: true)
 
       expect(user.valid?).to be_truthy
     end
 
     it 'should not allow a blacklisted user to be created' do
-      user = User.new(email: 'foo@mvrht.com', account: account, password: password)
+      user = User.new(email: 'foo@mvrht.com', account: account, password: password, agreement: true)
 
       expect(user.valid?).to be_falsey
     end
 
     it 'should not allow a subdomain blacklisted user to be created' do
-      user = User.new(email: 'foo@mvrht.com.topdomain.tld', account: account, password: password)
+      user = User.new(email: 'foo@mvrht.com.topdomain.tld', account: account, password: password, agreement: true)
 
       expect(user.valid?).to be_falsey
     end
@@ -210,17 +210,17 @@ RSpec.describe User, type: :model do
     end
 
     it 'should not allow a user to be created unless they are whitelisted' do
-      user = User.new(email: 'foo@example.com', account: account, password: password)
+      user = User.new(email: 'foo@example.com', account: account, password: password, agreement: true)
       expect(user.valid?).to be_falsey
     end
 
     it 'should allow a user to be created if they are whitelisted' do
-      user = User.new(email: 'foo@mastodon.space', account: account, password: password)
+      user = User.new(email: 'foo@mastodon.space', account: account, password: password, agreement: true)
       expect(user.valid?).to be_truthy
     end
 
     it 'should not allow a user with a whitelisted top domain as subdomain in their email address to be created' do
-      user = User.new(email: 'foo@mastodon.space.userdomain.com', account: account, password: password)
+      user = User.new(email: 'foo@mastodon.space.userdomain.com', account: account, password: password, agreement: true)
       expect(user.valid?).to be_falsey
     end
 
@@ -242,7 +242,7 @@ RSpec.describe User, type: :model do
 
   it_behaves_like 'Settings-extended' do
     def create!
-      User.create!(account: Fabricate(:account), email: 'foo@mastodon.space', password: 'abcd1234')
+      User.create!(account: Fabricate(:account), email: 'foo@mastodon.space', password: 'abcd1234', agreement: true)
     end
 
     def fabricate
diff --git a/spec/services/app_sign_up_service_spec.rb b/spec/services/app_sign_up_service_spec.rb
new file mode 100644
index 00000000000..d480df34808
--- /dev/null
+++ b/spec/services/app_sign_up_service_spec.rb
@@ -0,0 +1,41 @@
+require 'rails_helper'
+
+RSpec.describe AppSignUpService, type: :service do
+  let(:app) { Fabricate(:application, scopes: 'read write') }
+  let(:good_params) { { username: 'alice', password: '12345678', email: 'good@email.com', agreement: true } }
+
+  subject { described_class.new }
+
+  describe '#call' do