As part of changing the layout of my blog I wanted to add my latest Twitter status to the bottom left corner. It turned out to be very straight forward. Python has an excellent Twitter API — very litle code was required.

There’s two ways you could go about doing this. The first way is to write a template tag that would fetch the latest tweet, the other to create a context processor that would provide a tweet variable to your templates. I choose the latter.

Before we can start, the Twitter API module needs to be installed. You can find both the module and installation instruction over on google code: http://code.google.com/p/python-twitter/.

Note: I had to install the SVN version as there’s a bug in python-twitter version 0.5 when using Apache — it works fine using the development server.

To set up a context processor we first need to specify where Django can find our processors. This is done using the TEMPLATE_CONTEXT_PROCESSORS setting. Add the below to your project’s settings.py file.

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from django.conf.global_settings import TEMPLATE_CONTEXT_PROCESSORS

TEMPLATE_CONTEXT_PROCESSORS = TEMPLATE_CONTEXT_PROCESSORS + (
    "mysite.blog.context_processors.latest_tweet",
)

TWITTER_USER = "omh"
TWITTER_TIMEOUT = 3600

Django has bunch of context processors already defined in its global settings. If we only specify our processor, we would remove the default ones. If you want to keep the default processors — chances are you probably do — you could either manually add them — that doesn’t feel very DRY to me, or just append them like we do above.

Since we’re already editing settings.py we’ll go ahead and add two Twitter settings, TWITTER_USER to specify your Twitter login and TWITTER_TIMEOUT to specify how often we should ask Twitter for the latest tweet.

We specified mysite.blog.context_processors.latest_tweet as the context processor location. Next up is then to create a latest_tweet method inside of context_processors.py. Here’s what context_processors.py looks like:

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from datetime import datetime
from django.conf import settings
from django.core.cache import cache
import twitter

def latest_tweet( request ):
    tweet = cache.get( 'tweet' )

    if tweet:
        return {"tweet": tweet}

    tweet = twitter.Api().GetUserTimeline( settings.TWITTER_USER )[0]
    tweet.date = datetime.strptime( tweet.created_at, "%a %b %d %H:%M:%S +0000 %Y" )
    cache.set( 'tweet', tweet, settings.TWITTER_TIMEOUT )

    return {"tweet": tweet}

Django passes a HttpRequest object as the first and only parameter to all context processors. This is why we need to take request as a parameter, however in our case we don’t use it.

The above code is checking the cache for an existing tweet object. If the cache is empty it is uses the Twitter API to fetch the latest tweet, converts the date into a datetime object and stores the tweet in the cache.

With the context processor in place you can access the tweet object from any template loaded by any of the generic views. In your own views you need to use RequestContext instead of Context, as your context class when rendering templates.

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<div class="twitter">
    {% if tweet %}
        <p>Latest tweet from {{ tweet.date|naturalday }}: {{ tweet.text }}<p>
    {% endif %}
</div>