fix: Use BODY.PEEK[HEADER] to avoid parsing issues with mail providers

app/jobs/inboxes/fetch_imap_emails_job.rb

@@ -51,6 +51,11 @@ def process_message_id(channel, imap_client, message_id_with_seq)
 
     return if email_already_present?(channel, message_id)
 
+    if message_id.blank?
+      Rails.logger.info "[IMAP::FETCH_EMAIL_SERVICE] Empty message id for #{channel.email} with seq no. <#{seq_no}>."
+      return
+    end
+
     # Fetch the original mail content using the sequence no
     mail_str = imap_client.fetch(seq_no, 'RFC822')[0].attr['RFC822']
 
@@ -74,7 +79,7 @@ def fetch_message_ids_with_sequence(imap_client, channel)
     message_ids_with_seq = []
     seq_nums.each_slice(10).each do |batch|
       # Fetch only message-id only without mail body or contents.
-      batch_message_ids = imap_client.fetch(batch, 'BODY.PEEK[HEADER.FIELDS (MESSAGE-ID)]')
+      batch_message_ids = imap_client.fetch(batch, 'BODY.PEEK[HEADER]')
 
       # .fetch returns an array of Net::IMAP::FetchData or nil
       # (instead of an empty array) if there is no matching message.
@@ -85,7 +90,7 @@ def fetch_message_ids_with_sequence(imap_client, channel)
       end
 
       batch_message_ids.each do |data|
-        message_id = build_mail_from_string(data.attr['BODY[HEADER.FIELDS (MESSAGE-ID)]']).message_id
+        message_id = build_mail_from_string(data.attr['BODY[HEADER]']).message_id
         message_ids_with_seq.push([data.seqno, message_id])
       end
     end
@@ -97,7 +102,7 @@ def fetch_message_ids_with_sequence(imap_client, channel)
   # created between yesterday and today and returns message sequence numbers.
   # Return <message set>
   def fetch_available_mail_sequence_numbers(imap_client)
-    imap_client.search(['BEFORE', tomorrow, 'SINCE', yesterday])
+    imap_client.search(['SINCE', yesterday])
   end
 
   def fetch_mail_for_ms_provider(channel)
@@ -161,8 +166,4 @@ def valid_access_token(channel)
   def yesterday
     (Time.zone.today - 1).strftime('%d-%b-%Y')
   end
-
-  def tomorrow
-    (Time.zone.today + 1).strftime('%d-%b-%Y')
-  end
 end

spec/fixtures/files/mail_with_no_date.eml

@@ -2,5 +2,6 @@ Date:
 From: testemail@gmail.com
 To: imap@outlook.com
 Subject: test text only mail
+Message-Id: <0CB459E0-0336-41DA-BC88-E6E28C697DDB@chatwoot.com>
 
 text only mail

spec/jobs/inboxes/fetch_imap_emails_job_spec.rb

@@ -13,7 +13,6 @@
   let(:ms_email_inbox) { create(:inbox, channel: microsoft_imap_email_channel, account: account) }
   let!(:conversation) { create(:conversation, inbox: imap_email_channel.inbox, account: account) }
   let(:inbound_mail) { create_inbound_email_from_mail(from: 'testemail@gmail.com', to: 'imap@outlook.com', subject: 'Hello!') }
-  let(:inbound_mail_with_no_date) { create_inbound_email_from_fixture('mail_with_no_date.eml') }
   let(:inbound_mail_with_attachments) { create_inbound_email_from_fixture('multiple_attachments.eml') }
 
   it 'enqueues the job' do
@@ -53,25 +52,19 @@
     end
 
     it 'process the email with no date' do
-      email = Mail.new do
-        to 'test@outlook.com'
-        from 'test@gmail.com'
-        subject :test.to_s
-        body 'hello'
-      end
-
-      imap_fetch_mail = Net::IMAP::FetchData.new
-      imap_fetch_mail.attr = { seqno: 1, RFC822: email }.with_indifferent_access
+      fixture_path = Rails.root.join('spec/fixtures/files/mail_with_no_date.eml')
+      eml_content = File.read(fixture_path)
+      inbound_mail_with_no_date = create_inbound_email_from_fixture('mail_with_no_date.eml')
+      email_header = Net::IMAP::FetchData.new(1, 'BODY[HEADER]' => eml_content)
+      imap_fetch_mail = Net::IMAP::FetchData.new(1, 'RFC822' => eml_content)
 
       imap = double
-
       allow(Net::IMAP).to receive(:new).and_return(imap)
       allow(imap).to receive(:authenticate)
       allow(imap).to receive(:select)
       allow(imap).to receive(:search).and_return([1])
-      allow(imap).to receive(:fetch).and_return([imap_fetch_mail])
-
-      allow(Mail).to receive(:read_from_string).and_return(inbound_mail_with_no_date.mail)
+      allow(imap).to receive(:fetch).with([1], 'BODY.PEEK[HEADER]').and_return([email_header])
+      allow(imap).to receive(:fetch).with(1, 'RFC822').and_return([imap_fetch_mail])
 
       imap_mailbox = double