Skip to main content

Python and Gmail with IMAP

Today I had to automatically access my Gmail inbox from Python. I needed the ability to get an unread email count, the subjects of those unread emails and then download them. I found a Gmail.py library on sourceforge, but it actually opened the normal gmail webpage and site scraped the info. I wanted something much faster, luckily gmail can now be accessed with both pop and imap.

After a tiny amount of research I decided imap was the better albiet slightly more difficult protocol. Enabling imap in gmail is straight forward, it was under labs.

The address for gmail's imap server is:

imap.gmail.com:993

Python has a library module called imaplib, we will make heavy use of that to access our emails. I'm going to assume that we have already defined two globals - username and password. To connect and login to the gmail server and select the inbox we can do:

import imaplib

imap_server = imaplib.IMAP4_SSL("imap.gmail.com",993)
imap_server.login(username, password)

imap_server.select('INBOX')

All pretty straight forward so far, lets find out how many unread emails we have:

# Count the unread emails
status, response = imap_server.status('INBOX', "(UNSEEN)")
unreadcount = int(response[0].split()[2].strip(').,]'))
print unreadcount

Now I'm not saying this is a particularly nice way of doing this, but if you print the response and reverse engineer it you will see how I arrived with that string parsing. Regex would be another option, but I try avoid that unless it is required. Now lets get a list of the identifiers for each unread message, I'm going to call it email_ids:

# Search for all new mail
status, email_ids = imap_server.search(None, '(UNSEEN)')
print email_ids

If I want to download a particular list of messages, or maybe download the subjects for a list of messages I can use the following functions:

def get_emails(email_ids):
    data = []
    for e_id in email_ids:
        _, response = imap_server.fetch(e_id, '(UID BODY[TEXT])')
        data.append(response[0][1])
    return data

def get_subjects(email_ids):
    subjects = []
    for e_id in email_ids:
        _, response = imap_server.fetch(e_id, '(body[header.fields (subject)])')
        subjects.append( response[0][1][9:] )
    return subjects

And I often search for emails from someone in particular, I can do that easily from Python as well:

def emails_from(name):
    '''Search for all mail from name'''
    status, response = imap_server.search(None, '(FROM "%s")' % name)
    email_ids = [e_id for e_id in response[0].split()]
    print 'Number of emails from %s: %i. IDs: %s' % (name, len(email_ids), email_ids)
    return email_ids

Now this can all be combined to print the body of the latest 3 emails sent by my friend bob:

for email in get_emails(emails_from("bob")[-3:-1]):
    print email

Thats all folks!

Comments

  1. Thanks for the code! Building an LED array that scrolls new email subjects and this is exactly what I needed!

    ReplyDelete
  2. I'm getting a problem where it goes:

    Traceback (most recent call last):
    File "<\input>", line 1, in
    File "<\input>", line 4, in get_emails
    File "/usr/local/Cellar/python/2.7.2/lib/python2.7/imaplib.py", line 443, in fetch
    typ, dat = self._simple_command(name, message_set, message_parts)
    File "/usr/local/Cellar/python/2.7.2/lib/python2.7/imaplib.py", line 1070, in _simple_command
    return self._command_complete(name, self._command(name, *args))
    File "/usr/local/Cellar/python/2.7.2/lib/python2.7/imaplib.py", line 905, in _command_complete
    raise self.error('%s command error: %s %s' % (name, typ, data))
    error: FETCH command error: BAD ['Could not parse command']

    ReplyDelete
    Replies
    1. I got the same error. Did you find a resolution for the problem?

      Delete
  3. Hi there!

    Thanks for this. Am looking into building my own mailchecker for a non-Google imap server. This helped out a lot with that.

    Just a note: instead of:
    unreadcount = int(response[0].split()[2].strip(').,]'))

    You _could_ do:
    re.sub(r'\D', "",NAME_OF_VARIABLE)

    The above does require regex of course.

    Anyway, thanks again, much appreciated!

    ReplyDelete

Post a Comment

Popular posts from this blog

Matplotlib in Django

The official django tutorial is very good, it stops short of displaying
data with matplotlib - which could be very handy for dsp or automated
testing. This is an extension to the tutorial. So first you must do the
official tutorial!
Complete the tutorial (as of writing this up to part 4).

Adding an image to a view

To start with we will take a static image from the hard drive and
display it on the polls index page.
Usually if it really is a static image this would be managed by the
webserver eg apache. For introduction purposes we will get django to
serve the static image. To do this we first need to change the
template.



Change the template
At the moment poll_list.html probably looks something like this:


<h1>Django test app - Polls</h1> {% if object_list %} <ul> {% for object in object_list %} <li><a href="/polls/{{object.id}}">{{ object.question }}</a></li> {% endfor %} </ul> {% else %} <p>No polls are available.</p> …

Homomorphic encryption using RSA

I recently had cause to briefly look into Homomorphic Encryption, the process of carrying out computations on encrypted data. This technique allows for privacy preserving computation. Fully homomorphic encryption (FHE) allows both addition and multiplication, but is (currently) impractically slow.

Partially homomorphic encryption just has to meet one of these criteria and can be much more efficient.
An unintended, but well-known, malleability in the common RSA algorithm means that the multiplication of ciphertexts is equal to the multiplication of the original messages. So unpadded RSA is a partially homomorphic encryption system.

RSA is beautiful in how simple it is. See wikipedia to see how to generate the public (e, m) and private keys (d, m).

Given a message x it is encrypted with the public keys it to get the ciphertext C(x)with:

C(x)=xemodm
To decrypt a ciphertext

Bluetooth with Python 3.3

Since about version 3.3 Python supports Bluetooth sockets natively. To put this to the test I got hold of an iRacer from sparkfun. To send to New Zealand the cost was $60. The toy has an on-board Bluetooth radio that supports the RFCOMM transport protocol.



The drive protocol is dead easy, you send single byte instructions when a direction or speed change is required. The bytes are broken into two nibbles: 0xXY where X is the direction and Y is the speed. For example the byte 0x16 means forwards at mid-speed. I was surprised to note the car continues carrying out the last given demand!

I let pairing get dealt with by the operating system. The code to create a Car object that is drivable over Bluetooth is very straight forward in pure Python:

importsocketimporttimeclassBluetoothCar:def__init__(self,mac_address="00:12:05:09:98:36"):self.socket=socket.socket(socket.AF_BLUETOOTH,socket.SOCK_STREAM,socket.BTPROTO_RFCOMM)self.socket.connect((mac_address,1))def_write(self,data_byte):…