Parsing incoming mail with Google App Engine? - google-app-engine

Question

We have our mail setup with Google Apps. We want to be able to run some regular expressions on incoming mail and process this information.
Is this possible today with Google App Engine? Does Google provide some kind of infrastructure that can do this?

Answer 1

from google documentation here:
Receiving Mail
Your app can receive email at addresses of the following form:
string#appid.appspotmail.com
Note that even if your app is deployed on a custom domain, your app can't receive email sent to addresses on that domain.
Email messages are sent to your app as HTTP requests. These requests are generated by App Engine and posted to your app. In your app's configuration, you specify handlers that will be called to handle these HTTP requests. In your handlers, you receive the MIME data for email messages, which you then parse into its individual fields.
Email messages are sent to your app as HTTP POST requests using the following URL:
/_ah/mail/address
where address is a full email address, including domain name.
The ability to receive mail in your app is disabled by default. To enable your app to receive mail, you must specify that you want this service enabled in your app.yaml file by including this:
inbound_services:
- mail
The Python SDK defines InboundMailHandler, a webapp class for handling incoming email. To use InboundMailHandler, you subclass it and override the receive() method. The receive() method is called with an argument of class InboundEmailMessage, another class defined by the Python SDK.
InboundMailHandler is in the google.appengine.ext.webapp.mail_handlers package. You can create an instance of InboundEmailMessage like this:
import logging, email
from google.appengine.ext import webapp
from google.appengine.ext.webapp.mail_handlers import InboundMailHandler
from google.appengine.ext.webapp.util import run_wsgi_app
class LogSenderHandler(InboundMailHandler):
def receive(self, mail_message):
logging.info("Received a message from: " + mail_message.sender)
The InboundEmailMessage object includes attributes to access other message fields:
subject contains the message subject.
sender is the sender's email address.
to is a list of the message's primary recipients.
cc contains a list of the cc recipients.
date returns the message date.
attachments is a list of file attachments, possibly empty. Each value in the list is a tuple of two elements: the filename and the file contents.
original is the complete message, including data not exposed by the other fields such as email headers, as a Python email.message.Message.

Answer 2

handle_incoming_email.py
app.yaml

Answer 3

Update: It's now supported.
Processing incoming email is not yet supported. It is however on their roadmap: http://code.google.com/appengine/docs/roadmap.html

Answer 4

Google don't currently support handling email in App Engine, though it is on the roadmap. In the meantime, services like smtp2web will handle it for you (disclaimer: I wrote smtp2web).

Answer 5

You could setup an email account and have an external server (one you create and host outside of AE) access the gmail account via IMAP. Your "mail server" then reads the messages and accesses the /email API of your app on AE.
Python has an email module, so you could post the entire message there, or if that doesn't work (due to whatever restrictions), you could preprocess it on your mail server and post the simplified version to your app.
The downside is that you'll have to resort to polling for information, but that should be ok since email is accepted to have somewhat of a delay.

Answer 6

As another option to the answer from Gabriel I would recommend to use go environment of App Engine on Sending and Receiving Mail with the Mail API.
From The Documentation:
Receiving Mail
Your app can receive email at addresses of the following form:
anything#appid.appspotmail.com
Compare to a configuration on handling incoming mail in python as discussed here, enabling incoming mail in your app's app.yaml file is fairly simple:
inbound_services:
- mail
Name your app file as mail.go, then register a handler to the /_ah/mail/ path and read the email's data from the *http.Requestlike using net/mail like this:
func incomingMail(w http.ResponseWriter, r *http.Request) {
ctx := appengine.NewContext(r)
defer r.Body.Close()
var b bytes.Buffer
if _, err := b.ReadFrom(r.Body); err != nil {
log.Errorf(ctx, "Error reading body: %v", err)
return
}
log.Infof(ctx, "Received mail: %v", b)
}
Sending Mail
Follow this guideline to register your sender emails as authorized senders
Use the mail.Message type to set the sender, recipient, subject, and body of the message.
Send the email with the mail.Send function.
func confirm(w http.ResponseWriter, r *http.Request) {
ctx := appengine.NewContext(r)
addr := r.FormValue("email")
url := createConfirmationURL(r)
msg := &mail.Message{
Sender: "Example.com Support <support#example.com>",
To: []string{addr},
Subject: "Confirm your registration",
Body: fmt.Sprintf(confirmMessage, url),
}
if err := mail.Send(ctx, msg); err != nil {
log.Errorf(ctx, "Couldn't send email: %v", err)
}
}
Deploy
The complete sample code of both Receiving and Sending is available here on GitHub:
GoogleCloudPlatform/golang-samples/docs/appengine/mail/mail.go
To clone the sample code, go to your Console. Click the button to open Cloud Shell:
then similar with this quickstart enter the steps below:
$ SOURCEDIR=https://github.com/GoogleCloudPlatform/golang-samples.git
$ TUTORIALDIR=~/src/your-application-id/go_gae_samples
$ git clone $SOURCEDIR $TUTORIALDIR
$ cd $TUTORIALDIR
$ git checkout master
$ cat docs/appengine/mail/app.yaml
$ cat docs/appengine/mail/mail.go
$ goapp serve docs/appengine/mail/app.yaml
From here you can access the app on port 8080 by using Web preview.
To terminate press Ctrl+C in the Cloud Shell.
Finally you may deploy your app
goapp deploy -application your-application-id -version 0
Click the URL to visit it
http://your-application-id.appspot.com/
Then send an email to anything#your-application-id.appspotmail.com see if it works.