Add `POST /api/v1/emails/confirmations` to REST API (#15816)

Only available to the application the user originally signed-up with

app/controllers/api/v1/emails/confirmations_controller.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class Api::V1::Emails::ConfirmationsController < Api::BaseController
+  before_action :doorkeeper_authorize!
+  before_action :require_user_owned_by_application!
+
+  def create
+    current_user.resend_confirmation_instructions if current_user.unconfirmed_email.present?
+    render_empty
+  end
+
+  private
+
+  def require_user_owned_by_application!
+    render json: { error: 'This method is only available to the application the user originally signed-up with' }, status: :forbidden unless current_user && current_user.created_by_application_id == doorkeeper_token.application_id
+  end
+end

config/initializers/rack_attack.rb

@@ -94,11 +94,15 @@ class Rack::Attack
   end
 
   throttle('throttle_email_confirmations/ip', limit: 25, period: 5.minutes) do |req|
-    req.remote_ip if req.post? && req.path == '/auth/confirmation'
+    req.remote_ip if req.post? && %w(/auth/confirmation /api/v1/emails/confirmations).include?(req.path)
   end
 
   throttle('throttle_email_confirmations/email', limit: 5, period: 30.minutes) do |req|
-    req.params.dig('user', 'email').presence if req.post? && req.path == '/auth/password'
+    if req.post? && req.path == '/auth/password'
+      req.params.dig('user', 'email').presence
+    elsif req.post? && req.path == '/api/v1/emails/confirmations'
+      req.authenticated_user_id
+    end
   end
 
   throttle('throttle_login_attempts/ip', limit: 25, period: 5.minutes) do |req|

config/routes.rb

@@ -403,6 +403,10 @@ Rails.application.routes.draw do
 
       resources :apps, only: [:create]
 
+      namespace :emails do
+        resources :confirmations, only: [:create]
+      end
+
       resource :instance, only: [:show] do
         resources :peers, only: [:index], controller: 'instances/peers'
         resource :activity, only: [:show], controller: 'instances/activity'