Posts tagged: DJANGO

I love Django management commands.

For dpaste.com I’ve written several management commands for things that I don’t need a web UI for, like:

• expire - delete expired pastes (invoked by cron)
• expunge - manage TOS violations like spam
• stats - useful metrics on the current corpus of pastes, and on user activity

In running the site I also use management commands from my django-blocklist app, for tasks like deleting expired entries (via cron) or generating reports.

Python 3.8 (2019) added “assignment expressions”, aka the “walrus operator”.

I generally like things that make Python more expression-oriented, like list comprehensions, but I’m ambivalent about these. It’s pretty easy to impair readability by using them overzealously. Is saving one line of code worth making it harder to notice that an assignment is happening?

However, I’ve found a use case I like a lot. I use them in the Django Python shell when doing exploratory ORM queries.

In July I deployed a major update to dpaste.com. Nothing exploded. Good things resulted.

TLDR: Use python-future.

(Note: This is a writeup I did a few years ago when evaluating Riak KV as a possible data store for a high-traffic CMS. At the time, the product was called simply “Riak”. Naturally, other details may be out of date as well.)

Riak is a distributed, key/value store written in Erlang. It is open source but supported by a commercial company, Basho.

Its design is based on an Amazon creation called Dynamo, which is described in a 200-page paper published by Amazon. The engineers at Basho used this paper to guide the design of Riak.

Eight years ago, I launched a simple pastebin site written in Django.

In those early Django days I spent a lot of time in the #django IRC channel. I thought we should have a pastebin that knew how to correctly colorize our code, and which was written in our framework to boot. So I wrote one. Eventually its URL ended up in the channel topic, then in the Django source code itself.

Over the years, changes have been minimal. I switched from a Javascript-powered colorizer to Pygments. I added an API. I fixed things that broke. Mostly I just kept it running and usable. (I’ll also note that many excellent new pastebins were created in those years as well.)

A significant difference between developing Django sites versus static-HTML-based approaches (among which I count PHP and the like) is that static files, aka “media”, live in a dedicated spot.

Sometimes you need a piece of static content to be available at a specific URL outside your media root. robots.txt for example. This can be done in pure Django (i.e. without even touching your Apache configuration), and is especially nice if your robots.txt content is short. The example below serves a basic “keep out” configuration.