Email handler - custom bounce email with attachment

Question

I've developed a custom inbound email handler in order to be used with email-to-case, but, when some criteria are met, I need to "bounce" a custom email to the sender indicating some steps to follow and I need to have the inbound message attached to this "bounce" email.

I'm facing some issues with it, My apex code is something similar to this:

private void sendWarningEmail(){

  Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();

  String[] toAddresses = new String[] {this.inboundEmail.fromAddress}; 
  mail.setToAddresses(toAddresses);
  mail.setBccSender(false);
  mail.setUseSignature(false);
  mail.setSenderDisplayName('Sender Name');

  EmailTemplate et = [select Id, Subject, HtmlValue, Body from EmailTemplate where DeveloperName=:'Template'];
  mail.setTemplateId(et.id);

   //dummy contact to be the target object
  Contact c = new Contact();
  c.Email = this.inboundEmail.fromAddress;
  mail.setTargetObjectId(c.Id);


  //attach the original mail message
  Messaging.EmailFileAttachment efa = new Messaging.EmailFileAttachment();
  efa.setFileName(this.inboundEmail.subject);

  efa.setBody(Blob.valueof(this.inboundEmail.htmlBody));
  efa.setContentType('multipart/mixed');

  mail.setFileAttachments(new Messaging.EmailFileAttachment[] {efa});

  // Send the email you have created.
  Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });

}

I'm not sure about what the problem can be, but even when the attachement is created and added to the "bounced" email, it is "corrupted" or not in the correct format, because it cannot be opened.

What am I missing?

I hope someone can shed some light on this.

Answer 1

You don't show your inbound handler code, but unless the inbound body was saved as a 'multipart/mixed' ContentTyoe, I'd have expected it to be a Mime type of either 'HTML' or 'plaintext'.

That's what I'd be looking at, especially if you can't append their inbound message to the end of your outbound message body. I emphasize that since I don't see where you're sending any other attachments with this email.