Chore: Provide fixed attachment URLs for Channels (#4507)

Prior to this change, The attachment URL sent from Chatwoot to 3rd party integrations like Whatsapp and Facebook
involved a 301 redirect before the original content is served. This causes intermittent breakages for the sent attachments.

fixes: #3632
ref: https://blog.saeloun.com/2021/09/14/rails-7-adds-expiring-urls-to-active-storage.html

app/models/attachment.rb

@@ -44,12 +44,15 @@ class Attachment < ApplicationRecord
     base_data.merge(file_metadata)
   end
 
+  # NOTE: the URl returned does a 301 redirect to the actual file
   def file_url
     file.attached? ? url_for(file) : ''
   end
 
+  # NOTE: for External services use this methods since redirect doesn't work effectively in a lot of cases
   def download_url
-    file.attached? ? rails_storage_proxy_url(file) : ''
+    ActiveStorage::Current.host = Rails.application.routes.default_url_options[:host] if ActiveStorage::Current.host.blank?
+    file.attached? ? file.blob.url : ''
   end
 
   def thumb_url

app/models/channel/telegram.rb

@@ -95,7 +95,7 @@ class Channel::Telegram < ApplicationRecord
       when 'file'
         telegram_attachment[:type] = 'document'
       end
-      telegram_attachment[:media] = attachment.file_url
+      telegram_attachment[:media] = attachment.download_url
       telegram_attachments << telegram_attachment
     end
 

app/models/channel/whatsapp.rb

@@ -85,7 +85,7 @@ class Channel::Whatsapp < ApplicationRecord
   def send_attachment_message(phone_number, message)
     attachment = message.attachments.first
     type = %w[image audio video].include?(attachment.file_type) ? attachment.file_type : 'document'
-    attachment_url = attachment.file_url
+    attachment_url = attachment.download_url
     response = HTTParty.post(
       "#{api_base_path}/messages",
       headers: api_headers,

app/services/facebook/send_on_facebook_service.rb

@@ -36,7 +36,7 @@ class Facebook::SendOnFacebookService < Base::SendOnChannelService
         attachment: {
           type: attachment_type(attachment),
           payload: {
-            url: attachment.file_url
+            url: attachment.download_url
           }
         }
       },

app/services/instagram/send_on_instagram_service.rb

@@ -39,7 +39,7 @@ class Instagram::SendOnInstagramService < Base::SendOnChannelService
         attachment: {
           type: attachment_type(attachment),
           payload: {
-            url: attachment.file_url
+            url: attachment.download_url
           }
         }
       }

app/services/twilio/send_on_twilio_service.rb

@@ -25,7 +25,7 @@ class Twilio::SendOnTwilioService < Base::SendOnChannelService
   end
 
   def attachments
-    message.attachments.map(&:file_url)
+    message.attachments.map(&:download_url)
   end
 
   def inbox

config/environments/test.rb

@@ -20,8 +20,8 @@ Rails.application.configure do
   config.public_file_server.headers = {
     'Cache-Control' => "public, max-age=#{1.hour.to_i}"
   }
-  config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
+  config.action_mailer.default_url_options = { host: 'http://localhost:3000' }
-  Rails.application.routes.default_url_options = { host: 'localhost', port: 3000 }
+  Rails.application.routes.default_url_options = { host: 'http://localhost:3000' }
 
   # Show full error reports and disable caching.
   config.consider_all_requests_local       = true

lib/integrations/slack/send_on_slack_service.rb

@@ -73,7 +73,7 @@ class Integrations::Slack::SendOnSlackService < Base::SendOnChannelService
   end
 
   def file_type
-    File.extname(message.attachments.first.file_url).strip.downcase[1..]
+    File.extname(message.attachments.first.download_url).strip.downcase[1..]
   end
 
   def file_information

spec/models/attachment_spec.rb

@@ -0,0 +1,12 @@
+require 'rails_helper'
+
+RSpec.describe Attachment, type: :model do
+  describe 'download_url' do
+    it 'returns valid download url' do
+      message = create(:message)
+      attachment = message.attachments.new(account_id: message.account_id, file_type: :image)
+      attachment.file.attach(io: File.open(Rails.root.join('spec/assets/avatar.png')), filename: 'avatar.png', content_type: 'image/png')
+      expect(attachment.download_url).not_to eq nil
+    end
+  end
+end

spec/services/facebook/send_on_facebook_service_spec.rb

@@ -57,6 +57,7 @@ describe Facebook::SendOnFacebookService do
         attachment = message.attachments.new(account_id: message.account_id, file_type: :image)
         attachment.file.attach(io: File.open(Rails.root.join('spec/assets/avatar.png')), filename: 'avatar.png', content_type: 'image/png')
         message.save!
+        allow(attachment).to receive(:download_url).and_return('url1')
         ::Facebook::SendOnFacebookService.new(message: message).perform
         expect(bot).to have_received(:deliver).with({
                                                       recipient: { id: contact_inbox.source_id },
@@ -70,7 +71,7 @@ describe Facebook::SendOnFacebookService do
                                                         attachment: {
                                                           type: 'image',
                                                           payload: {
-                                                            url: attachment.file_url
+                                                            url: 'url1'
                                                           }
                                                         }
                                                       },

spec/services/sms/send_on_sms_service_spec.rb

@@ -36,12 +36,14 @@ describe Sms::SendOnSmsService do
         allow(HTTParty).to receive(:post).and_return(sms_request)
         allow(sms_request).to receive(:success?).and_return(true)
         allow(sms_request).to receive(:parsed_response).and_return({ 'id' => '123456789' })
+        allow(attachment).to receive(:download_url).and_return('url1')
+        allow(attachment2).to receive(:download_url).and_return('url2')
         expect(HTTParty).to receive(:post).with(
           'https://messaging.bandwidth.com/api/v2/users/1/messages',
           basic_auth: { username: '1', password: '1' },
           headers: { 'Content-Type' => 'application/json' },
           body: { 'to' => '+123456789', 'from' => sms_channel.phone_number, 'text' => 'test', 'applicationId' => '1',
-                  'media' => [attachment.download_url, attachment2.download_url] }.to_json
+                  'media' => %w[url1 url2] }.to_json
         )
         described_class.new(message: message).perform
         expect(message.reload.source_id).to eq('123456789')