When use AWS Lambda to process mails from mailgun, can't get mails in JSON format

Question

What I am tried to do is to have a lambda function proccess emails forwarded by mailgun.

So far, I have setup mailgun's route so it will forward emails to a AWS api gateway, then the api gateway triggers a lambda function.

The problem comes when I try to process the mail, instead of getting a pretty Json that I am expecting inside the lambda's event.body, I m getting raw post form data like

--cff4e6b3-a3a4-4131-bb8d-90a73f1b4c36\r\nContent-Disposition: form-data; name=\"Content-Type\"\r\n\r\nmultipart/mixed; boundary=\"001a1140216cee404d05440c49e7\"\r\n--cff4e6b3-a3a4-4131-bb8d-90a73f1b4c36\r\nContent-Disposition: form-data; name=\"Date\"\r\n\r\nTue, 20 Dec 2016 13:40:53 +1300\r\n--cff4e6b3-a3a4-4131-bb8d-90a73f1b4c36\r\nContent ......

My question is, what should I do to get the JSON version of the forwarded emails in lambda?

Answer 1

Not sure if you ever came to a solution, but I have this working with the following settings.

1. Setup your API Gateway method to use "Use Lambda Proxy integration"
2. In your lambda (I use node.js) use busboy to work through the multi-part submission from mailgun. (use this post for help with busboy Busboy help)
3. Make sure that any code you are going to execute after all busboy is complete is executed in the 'finish' portion of the busboy code.

Answer 2

This suggests that your mailgun route is misconfigured and ends with a MIME request:

When you specify a URL of your application as a route destination through a forward() action, Mailgun will perform an HTTP POST request into it using one of two following formats:

Fully parsed: Mailgun will parse the message, transcode it into UTF-8 encoding, process attachments, and attempt to separate quoted parts from the actual message. This is the preferred option.

Raw MIME: message is posted as-is. In this case you are responsible for parsing MIME. To receive raw MIME messages, the destination URL must end with mime

From Receiving Messages via HTTP through a forward() action