Simon Willison’s Weblog

501 items tagged “django”

Django (web framework): What is the recommended way to cache objects that are very large (>1.5MB)?

Take a look at redis—it can handle binary strings up to 512 MB and has performance that is similar to memcache. It’s very easy to use from within Django (there’s even a pluggable cache backend for it).

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How can I learn more about server-side technologies?

Get yourself a VPS, set it up from scratch and run some non-critical websites on it (nothing with private user data since you can’t be sure you’ll set it up securely). Both Slicehost and Linode offer a good set of guides to a whole host of common tasks:

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How do you organize the code in your Django project?

For http://lanyrd.com/ our layout looks something like this:

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Why doesn’t the Django framework come with its own REST API out of the box?

I’d argue that it does. If you want to build a REST API you need to be able to map incoming HTTP requests to handler functions based on their URL, run some custom code and return an HTTP response containing JSON (or maybe XML). Django makes all of this really simple.

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What web programming framework best supports ’drag and drop’ actions?  Please give examples of sites and/or plug-ins that support the interaction.

Drag and drop is a client-side thing—it has nothing to do with the server-side technology being used.

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Python Django load MySQL database from csv files performance issue?

Don’t use the Django ORM for bulk imports—the performance overhead is pretty small for regular web page stuff, but it adds up if you are running millions of inserts.

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How can I look up Django functions?

You can use the ./manage.py shell command to get a shell which will import any Django modules (or any of your own code) without complaining about the location of the settings.py module. Install IPython first to get a much more useful interactive shell when you run that command.

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How can I install Django in a server without shell access?

I don’t think you can.

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Do Python programmers have a tendency to write their own software instead of contributing? Why?

I think you’ll find that PROGRAMMERS have a tendency to develop their own thing rather than contributing to an existing project. It’s even got its own TLA: NIH (Not Invented Here).

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Play Framework, Django or Rails? Which one do you recommend for  Social Networking Web applications.

Both Rails and Django have been used for a large number of high profile social networking web applications. Off the top of my head, Django is used by Instagram and Pinterest, Rails is used by Posterous and Ravelry. I don’t know what the largest sites built using Play are at the moment.

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Are there any good Django video tutorials?

ShowMeDo has 55 video screencasts covering all sorts of aspects of Django development: http://showmedo.com/videotutoria...

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Is Django on its way out?

Not as far as I can tell—but then like many (most?) other Django users I’m too busy using it to build things to worry too much about whether or not it’s fashionable.

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Is there a way to find out what apps are used by a specific django-based website?

Not really. You might be able to figure out some of them by looking out for common patterns of URLs and form field names, but a lot of reusable django apps don’t really expose much of a signature.

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What are you some good blogs, videos, papers, etc. on scaling Django?

We’re building up a pretty sizable collection of video (and slides) from talks about Django on http://lanyrd.com/—including plenty that talk about scaling issues. Try this: http://lanyrd.com/search/?q=djan...—we have 16 videos and 16 slide decks from talks at events all over the world.

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Why does Django still not have support for multiple joins?

I don’t fully understand the question, but if you’re talking about doing a single join across multiple tables the Django ORM handles that just fine. Let’s say you want to get every BlogEntry written by a User who belongs to the Group with the name “admins”:

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CSRF: Flash + 307 redirect = Game Over. Here’s the exploit that Django and Rails both just released fixes for. It’s actually a flaw in the Flash player. Flash isn’t meant to be able to make cross-domain HTTP requests with custom HTTP headers unless the crossdomain.xml file on the other domain allows them to, but it turns out a 307 redirect (like a 302, but allows POST data to be forwarded) confuses the Flash player in to not checking the crossdomain.xml on the host it is being redirect to. # 10th February 2011, 10:07 pm

Is South the best tool to use when doing database migrations in Django?

Yes. And I say that as an author of another Django migrations tool (dmigrations) which offered a small subset of South’s current functionality.

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Which web server suits Django best? Apache, Nginx or something else?

I’m still a big fan of a stripped down Apache+mod_wsgi running behind nginx.

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What is the best way to debug a Django app?

The Django Debug Toolbar is essential: http://robhudson.github.com/djan...

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The First Few Weeks—ep.io. Another take on managed Python Django/WSGI hosting, from Andrew Godwin and Ben Firshman. # 13th January 2011, 4:25 am

Hello from Gondor. “Effortless production Django hosting” from the Eldarion team. # 13th January 2011, 4:24 am

Why isn’t the schema and data migration tool South included in Django by default?

Because shipping things as part of Django means they can’t have separate releases, which means you only get a new released version every 6-12 months. South is improving far faster than that.

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What are the tradeoffs (e.g. development speed, performance, scalability) between using various php frameworks, ruby/rails, or python/django?  Is there any reason to choose one overwhelmingly over another?

At this point, I’d argue that the decision between them comes down to programming language rather than framework—the frameworks have mostly converged on a very similar set of features.

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Is Django a good option for crowdsourcing site?

Yes. I’ve built multiple crowdsourcing sites using Django, including http://mps-expenses2.guardian.co... , http://www.wildlifenearyou.com/ and http://lanyrd.com/

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What is the best way to integrate MongoDB with Django?

Personally, I just “import pymongo” and start calling the regular Python API—no need for any special treatment to get it working with Django.

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Bleach, HTML sanitizer and auto-linker. HTML sanitisation is notoriously difficult to do correctly, but Bleach (a Python library) looks like an excellent effort. It uses the html5lib parsing library to deal with potentially malformed HTML, uses a whitelist rather than a blacklist and has a neat feature for auto-linking URLs that is aware of the DOM (so it won’t try to auto-link a URL that is already wrapped in a link element). It was written by the Mozilla team for addons.mozilla.org and support.mozilla.org so it should be production ready. # 25th October 2010, 1:32 pm

What does an ideal Django workflow setup look like?

Short answer: virtualenv, pip, south for migrations, fabric for deployment.

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Who are the best Python developers in Los Angeles?

Mahalo is based in Santa Monica, and they have a very talented team of Python/Django people. They also host a regular Django meetup: http://www.meetup.com/ladjango/

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What’s the easiest way to take an existing Django view and make it “real time” via long polling?

I’d advocate decoupling your long polling endpoints entirely from the rest of your web app stack. Personally I like Node.js for this, but Tornado would work just fine too (I’ve experimented successfully with Tornado long polling in the past).

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Django (web framework): Why did theonion.com stop using Drupal?

They wrote about their reasons in detail in a post to the Django sub-reddit a while ago: http://www.reddit.com/r/django/c...

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