Google App Engine python inbound mail LookupError: unknown encoding

Question

I am receiving inbound email to my Google App Engine app, using a \"standard\" inbound mail handler, following the examples in the docs.

It seems that a certain emai

Answer 1

The error is happening when the inbound mail handler's post method is called.

  File "/base/data/home/runtimes/python27/python27_lib/versions/1/google/appengine/ext/webapp/mail_handlers.py", line 70, in post
    self.receive(mail.InboundEmailMessage(self.request.body))

The simplest solution is to override the post method in your own handler to trap the error:

import logging
from google.appengine.ext.webapp.mail_handlers import InboundMailHandler


class MyInboundMailHandler(InboundMailHandler):

    def post(self):
        try:
            super(MyInboundMailHandler, self).post()
        except LookupError as ex:
            logging.warning('Could not process message because %s.', ex)

    def receive(self, mail_message):
        # Process message

If you don't want to lose the message, you could create and register a custom iso-8859-8-i codec. This doesn't seem to be a well-documented process, but these questions provide some hints:

How do I properly create custom text codecs?

Custom Python Charmap Codec

how do I write a custom encoding in python to clean up my data?

And the standard library's iso-8859-8 encoding provides a good template.