feat: Support Azure single-tenant application using the Graph API (#6728) (#6878)

app/jobs/inboxes/fetch_imap_email_inboxes_job.rb

@@ -2,8 +2,19 @@ class Inboxes::FetchImapEmailInboxesJob < ApplicationJob
   queue_as :scheduled_jobs
 
   def perform
+    # check imap_enabled for channel
     Inbox.where(channel_type: 'Channel::Email').all.find_each(batch_size: 100) do |inbox|
-      ::Inboxes::FetchImapEmailsJob.perform_later(inbox.channel) if inbox.channel.imap_enabled
+      next unless inbox.channel.imap_enabled?
+
+      fetch_emails(inbox)
+    end
+  end
+
+  def fetch_emails(inbox)
+    if inbox.channel.microsoft? && ENV.fetch('AZURE_TENANT_ID', false)
+      ::Inboxes::FetchMsGraphEmailForTenantJob.perform_later(inbox.channel)
+    else
+      ::Inboxes::FetchImapEmailsJob.perform_later(inbox.channel)
     end
   end
 end

app/jobs/inboxes/fetch_ms_graph_email_for_tenant_job.rb

@@ -0,0 +1,101 @@
+require 'net/http'
+
+class Inboxes::FetchMsGraphEmailForTenantJob < ApplicationJob
+  queue_as :scheduled_jobs
+
+  def perform(channel)
+    process_email_for_channel(channel)
+  rescue EOFError => e
+    Rails.logger.error e
+  rescue StandardError => e
+    ChatwootExceptionTracker.new(e, account: channel.account).capture_exception
+  end
+
+  private
+
+  def should_fetch_email?(channel)
+    channel.imap_enabled? && channel.microsoft? && !channel.reauthorization_required?
+  end
+
+  def process_email_for_channel(channel)
+    # fetching email for microsoft provider
+    fetch_mail_for_channel(channel)
+
+    # clearing old failures like timeouts since the mail is now successfully processed
+    channel.reauthorized!
+  end
+
+  def fetch_mail_for_channel(channel)
+    return if channel.provider_config['access_token'].blank?
+
+    access_token = valid_access_token channel
+
+    return unless access_token
+
+    graph = graph_authenticate(access_token)
+
+    process_mails(graph, channel)
+  end
+
+  def process_mails(graph, channel)
+    response = graph.get_from_api('me/messages', {}, graph_query)
+
+    unless response.is_a?(Net::HTTPSuccess)
+      channel.authorization_error!
+      return false
+    end
+
+    json_response = JSON.parse(response.body)
+    json_response['value'].each do |message|
+      inbound_mail = Mail.read_from_string retrieve_mail_mime(graph, message['id'])
+
+      next if channel.inbox.messages.find_by(source_id: inbound_mail.message_id).present?
+
+      process_mail(inbound_mail, channel)
+    end
+  end
+
+  def retrieve_mail_mime(graph, id)
+    response = graph.get_from_api("me/messages/#{id}/$value")
+    return unless response.is_a?(Net::HTTPSuccess)
+
+    response.body
+  end
+
+  def graph_authenticate(access_token)
+    MicrosoftGraphApi.new(access_token)
+  end
+
+  def yesterday
+    (Time.zone.today - 1).strftime('%FT%TZ')
+  end
+
+  def tomorrow
+    (Time.zone.today + 1).strftime('%FT%TZ')
+  end
+
+  # Query to replicate the IMAP search used in Inboxes::FetchImapEmailsJob
+  # Selects the top 1000 records within the given filter, as that is the maximum
+  # page size for the API. Might need to look into paginating the requests later,
+  # for inboxes that receive more than 1000 emails a day?
+  #
+  # 1. https://learn.microsoft.com/en-us/graph/api/user-list-messages
+  # 2. https://learn.microsoft.com/en-us/graph/query-parameters
+  def graph_query
+    {
+      '$filter': "receivedDateTime ge #{yesterday} and receivedDateTime le #{tomorrow}",
+      '$top': '1000', '$select': 'id'
+    }
+  end
+
+  def process_mail(inbound_mail, channel)
+    Imap::ImapMailbox.new.process(inbound_mail, channel)
+  rescue StandardError => e
+    ChatwootExceptionTracker.new(e, account: channel.account).capture_exception
+  end
+
+  # Making sure the access token is valid for microsoft provider
+  def valid_access_token(channel)
+    Microsoft::RefreshOauthTokenService.new(channel: channel).access_token
+  end
+end