leadsift / whitenoise

Radically simplified static file serving for Python web apps

WhiteNoise

Radically simplified static file serving for Python web apps

With a couple of lines of config WhiteNoise allows your web app to serve its own static files, making it a self-contained unit that can be deployed anywhere without relying on nginx, Amazon S3 or any other external service. (Especially useful on Heroku, OpenShift and other PaaS providers.)

It's designed to work nicely with a CDN for high-traffic sites so you don't have to sacrific performance to benefit from simplicity.

WhiteNoise works with any WSGI-compatible app but has some special auto-configuration features for Django.

WhiteNoise takes care of best-practices for you, for instance:

• Serving gzipped content (handling Accept-Encoding and Vary headers correctly)
• Setting far-future cache headers on content which won't change

Worried that serving static files with Python is horribly inefficient? Still think you should be using Amazon S3? Have a look at the Infrequently Asked Questions below.

QuickStart for Django apps

Edit your wsgi.py file and wrap your WSGI application like so:

from django.core.wsgi import get_wsgi_application
from whitenoise.django import DjangoWhiteNoise

application = get_wsgi_application()
application = DjangoWhiteNoise(application)

That's it, you're ready to go.

Want forever-cachable files and gzip support? Just add this to your settings.py:

STATICFILES_STORAGE = 'whitenoise.django.GzipManifestStaticFilesStorage'

For more details, including on setting up CloudFront and other CDNs see the Using WhiteNoise with Django guide.

QuickStart for other WSGI apps

To enable WhiteNoise you need to wrap your existing WSGI application in a WhiteNoise instance and tell it where to find your static files. For example:

from whitenoise import WhiteNoise

from my_project import MyWSGIApp

application = MyWSGIApp()
application = WhiteNoise(application, root='/path/to/static/files')
application.add_files('/path/to/more/static/files', prefix='more-files/')

And that's it, you're ready to go. For more details see the full documentation.

Compatibility

WhiteNoise works with any WSGI-compatible application and is tested on Python 2.7, 3.3, 3.4 and PyPy.

DjangoWhiteNoise is tested with Django versions 1.4 --- 1.7

Endorsements

WhiteNoise is being used in Warehouse, the in-development replacement for the PyPI package repository.

Some of Django and pip's core developers have said nice things about it:

@jezdez: [WhiteNoise] is really awesome and should be the standard for Django + Heroku

@dstufft: WhiteNoise looks pretty excellent.

@idangazit Received a positive brainsmack from @_EvansD's WhiteNoise. Vastly smarter than S3 for static assets. What was I thinking before?

Issues & Contributing

Raise an issue on the GitHub project or feel free to nudge @_EvansD on Twitter.

Infrequently Asked Questions

Isn't serving static files from Python horribly inefficient?

The short answer to this is that if you care about performance and efficiency then you should be using WhiteNoise behind a CDN like CloudFront. If you're doing that then, because of the caching headers WhiteNoise sends, the vast majority of static requests will be served directly by the CDN without touching your application, so it really doesn't make much difference how efficient WhiteNoise is.

That said, WhiteNoise is pretty efficient. Because it only has to serve a fixed set of files it does all the work of finding files and determing the correct headers upfront on initialization. Requests can then be served with little more than a dictionary lookup to find the appropriate response. Also, when used with gunicorn (and most other WSGI servers) the actual business of pushing the file down the network interface is handled by the kernel's very efficient sendfile syscall, not by Python.

Shouldn't I be pushing my static files to S3 using something like Django-Storages?

No, you shouldn't. The main problem with this approach is that Amazon S3 cannot currently selectively serve gzipped content to your users. Gzipping can make dramatic reductions in the bandwidth required for your CSS and JavaScript. But while all browsers in use today can decode gzipped content, your users may be behind crappy corporate proxies or anti-virus scanners which don't handle gzipped content properly. Amazon S3 forces you to choose whether to serve gzipped content to no-one (wasting bandwidth) or everyone (running the risk of your site breaking for certain users).

The correct behaviour is to examine the Accept-Encoding header of the request to see if gzip is supported, and to return an appropriate Vary header so that intermediate caches know to do the same thing. This is exactly what WhiteNoise does.

The second problem with a push-based approach to handling static files is that it adds complexity and fragility to your deployment process: extra libraries specific to your storage backend, extra configuration and authentication keys, and extra tasks that must be run at specific points in the deployment in order for everythig to work. With the CDN-as-caching-proxy approach that WhiteNoise takes there are just two bits of configuration: your application needs the URL of the CDN, and the CDN needs the URL of your application. Everything else is just standard HTTP semantics. This makes your deployments simpler, your life easier, and you happier.

License

MIT Licensed