Skip to content

Latest commit

 

History

History
737 lines (486 loc) · 27.4 KB

django.rst

File metadata and controls

737 lines (486 loc) · 27.4 KB
Raw

Using WhiteNoise with Django

Note

To use WhiteNoise with a non-Django application see the :doc:`generic WSGI documentation <base>`.

This guide walks you through setting up a Django project with WhiteNoise. In most cases it shouldn't take more than a couple of lines of configuration.

I mention Heroku in a few places as that was the initial use case which prompted me to create WhiteNoise, but there's nothing Heroku-specific about WhiteNoise and the instructions below should apply whatever your hosting platform.

1. Make sure staticfiles is configured correctly

If you're familiar with Django you'll know what to do. If you're just getting started with a new Django project then you'll need add the following to the bottom of your settings.py file:

STATIC_ROOT = BASE_DIR / 'staticfiles'

As part of deploying your application you'll need to run ./manage.py collectstatic to put all your static files into STATIC_ROOT. (If you're running on Heroku then this is done automatically for you.)

Make sure you're using the static template tag to refer to your static files, rather that writing the URL directly. For example:

{% load static %}
<img src="{% static "images/hi.jpg" %}" alt="Hi!" />

<!-- DON'T WRITE THIS -->
<img src="/static/images/hi.jpg" alt="Hi!" />

For further details see the Django staticfiles guide.

2. Enable WhiteNoise

Edit your settings.py file and add WhiteNoise to the MIDDLEWARE list. The WhiteNoise middleware should be placed directly after the Django SecurityMiddleware (if you are using it) and before all other middleware:

MIDDLEWARE = [
  'django.middleware.security.SecurityMiddleware',
  'whitenoise.middleware.WhiteNoiseMiddleware',
  # ...
]

That's it -- WhiteNoise will now serve your static files (you can confirm it's working using the :ref:`steps below <check-its-working>`). However, to get the best performance you should proceed to step 3 below and enable compression and caching.

Note

You might find other third-party middleware that suggests it should be given highest priority at the top of the middleware list. Unless you understand exactly what is happening you should ignore this advice and always place WhiteNoiseMiddleware above other middleware. If you plan to have other middleware run before WhiteNoise you should be aware of the request_finished bug in Django.

3. Add compression and caching support

WhiteNoise comes with a storage backend which automatically takes care of compressing your files and creating unique names for each version so they can safely be cached forever. To use it, just add this to your settings.py:

STATICFILES_STORAGE = 'whitenoise.storage.CompressedManifestStaticFilesStorage'

This combines automatic compression with the caching behaviour provided by Django's ManifestStaticFilesStorage backend. If you want to apply compression but don't want the caching behaviour then you can use:

STATICFILES_STORAGE = 'whitenoise.storage.CompressedStaticFilesStorage'

Note

If you are having problems after switching to the WhiteNoise storage backend please see the :ref:`troubleshooting guide <storage-troubleshoot>`.

If you need to compress files outside of the static files storage system you can use the supplied :ref:`command line utility <cli-utility>`

Brotli compression

As well as the common gzip compression format, WhiteNoise supports the newer, more efficient brotli format. This helps reduce bandwidth and increase loading speed. To enable brotli compression you will need the Brotli Python package installed by running pip install whitenoise[brotli].

Brotli is supported by all major browsers (except IE11). WhiteNoise will only serve brotli data to browsers which request it so there are no compatibility issues with enabling brotli support.

Also note that browsers will only request brotli data over an HTTPS connection.

4. Use a Content-Delivery Network

The above steps will get you decent performance on moderate traffic sites, however for higher traffic sites, or sites where performance is a concern you should look at using a CDN.

Because WhiteNoise sends appropriate cache headers with your static content, the CDN will be able to cache your files and serve them without needing to contact your application again.

Below are instruction for setting up WhiteNoise with Amazon CloudFront, a popular choice of CDN. The process for other CDNs should look very similar though.

Instructions for Amazon CloudFront

Go to CloudFront section of the AWS Web Console, and click "Create Distribution". Put your application's domain (without the http prefix) in the "Origin Domain Name" field and leave the rest of the settings as they are.

It might take a few minutes for your distribution to become active. Once it's ready, copy the distribution domain name into your settings.py file so it looks something like this:

STATIC_HOST = 'https://d4663kmspf1sqa.cloudfront.net' if not DEBUG else ''
STATIC_URL = STATIC_HOST + '/static/'

Or, even better, you can avoid hardcoding your CDN into your settings by doing something like this:

STATIC_HOST = os.environ.get('DJANGO_STATIC_HOST', '')
STATIC_URL = STATIC_HOST + '/static/'

This way you can configure your CDN just by setting an environment variable. For apps on Heroku, you'd run this command

heroku config:set DJANGO_STATIC_HOST=https://d4663kmspf1sqa.cloudfront.net

Using compression algorithms other than gzip

By default, CloudFront will discard any Accept-Encoding header browsers include in requests, unless the value of the header is gzip. If it is gzip, CloudFront will fetch the uncompressed file from the origin, compress it, and return it to the requesting browser.

To get CloudFront to not do the compression itself as well as serve files compressed using other algorithms, such as Brotli, you must configure your distribution to `cache based on the Accept-Encoding header`__. You can do this in the Behaviours tab of your distribution.

Note

By default your entire site will be accessible via the CloudFront URL. It's possible that this can cause SEO problems if these URLs start showing up in search results. You can restrict CloudFront to only proxy your static files by following :ref:`these directions <restricting-cloudfront>`.

5. Using WhiteNoise in development

In development Django's runserver automatically takes over static file handling. In most cases this is fine, however this means that some of the improvements that WhiteNoise makes to static file handling won't be available in development and it opens up the possibility for differences in behaviour between development and production environments. For this reason it's a good idea to use WhiteNoise in development as well.

You can disable Django's static file handling and allow WhiteNoise to take over simply by passing the --nostatic option to the runserver command, but you need to remember to add this option every time you call runserver. An easier way is to edit your settings.py file and add whitenoise.runserver_nostatic to the top of your INSTALLED_APPS list:

INSTALLED_APPS = [
    'whitenoise.runserver_nostatic',
    'django.contrib.staticfiles',
    # ...
]

Note

In older versions of WhiteNoise (below v4.0) it was not possible to use runserver_nostatic with Channels as Channels provides its own implementation of runserver. Newer versions of WhiteNoise do not have this problem and will work with Channels or any other third-party app that provides its own implementation of runserver.

6. Index Files

When the :any:`WHITENOISE_INDEX_FILE` option is enabled:

  • Visiting /example/ will serve the file at /example/index.html
  • Visiting /example will redirect (302) to /example/
  • Visiting /example/index.html will redirect (302) to /example/

If you want to something other than index.html as the index file, then you can also set this option to an alternative filename.

Available Settings

The WhiteNoiseMiddleware class takes all the same configuration options as the WhiteNoise base class, but rather than accepting keyword arguments to its constructor it uses Django settings. The setting names are just the keyword arguments upper-cased with a 'WHITENOISE_' prefix.

.. attribute:: WHITENOISE_ROOT

    :default: ``None``

    Absolute path to a directory of files which will be served at the root of
    your application (ignored if not set).

    Don't use this for the bulk of your static files because you won't benefit
    from cache versioning, but it can be convenient for files like
    ``robots.txt`` or ``favicon.ico`` which you want to serve at a specific
    URL.


.. attribute:: WHITENOISE_AUTOREFRESH

    :default: ``settings.DEBUG``

    Recheck the filesystem to see if any files have changed before responding.
    This is designed to be used in development where it can be convenient to
    pick up changes to static files without restarting the server. For both
    performance and security reasons, this setting should not be used in
    production.


.. attribute:: WHITENOISE_USE_FINDERS

    :default: ``settings.DEBUG``

    Instead of only picking up files collected into ``STATIC_ROOT``, find and
    serve files in their original directories using Django's "finders" API.
    This is useful in development where it matches the behaviour of the old
    ``runserver`` command. It's also possible to use this setting in
    production, avoiding the need to run the ``collectstatic`` command during
    the build, so long as you do not wish to use any of the caching and
    compression features provided by the storage backends.


.. attribute:: WHITENOISE_MAX_AGE

    :default: ``60 if not settings.DEBUG else 0``

    Time (in seconds) for which browsers and proxies should cache **non-versioned** files.

    Versioned files (i.e. files which have been given a unique name like *base.a4ef2389.css* by
    including a hash of their contents in the name) are detected automatically and set to be
    cached forever.

    The default is chosen to be short enough not to cause problems with stale versions but
    long enough that, if you're running WhiteNoise behind a CDN, the CDN will still take
    the majority of the strain during times of heavy load.



.. attribute:: WHITENOISE_INDEX_FILE

    :default: ``False``

    If ``True`` enable :ref:`index file serving <index-files-django>`. If set to a non-empty
    string, enable index files and use that string as the index file name.



.. attribute:: WHITENOISE_MIMETYPES

    :default: ``None``

    A dictionary mapping file extensions (lowercase) to the mimetype for that
    extension. For example: ::

        {'.foo': 'application/x-foo'}

    Note that WhiteNoise ships with its own default set of mimetypes and does
    not use the system-supplied ones (e.g. ``/etc/mime.types``). This ensures
    that it behaves consistently regardless of the environment in which it's
    run.  View the defaults in the :file:`media_types.py
    <whitenoise/media_types.py>` file.

    In addition to file extensions, mimetypes can be specified by supplying the entire
    filename, for example: ::

        {'some-special-file': 'application/x-custom-type'}



.. attribute:: WHITENOISE_CHARSET

    :default: ``'utf-8'``

    Charset to add as part of the ``Content-Type`` header for all files whose
    mimetype allows a charset.



.. attribute:: WHITENOISE_ALLOW_ALL_ORIGINS

    :default: ``True``

    Toggles whether to send an ``Access-Control-Allow-Origin: *`` header for all
    static files.

    This allows cross-origin requests for static files which means your static files
    will continue to work as expected even if they are served via a CDN and therefore
    on a different domain. Without this your static files will *mostly* work, but you
    may have problems with fonts loading in Firefox, or accessing images in canvas
    elements, or other mysterious things.

    The W3C `explicitly state`__ that this behaviour is safe for publicly
    accessible files.


.. attribute:: WHITENOISE_SKIP_COMPRESS_EXTENSIONS

    :default: ``('jpg', 'jpeg', 'png', 'gif', 'webp','zip', 'gz', 'tgz', 'bz2', 'tbz', 'xz', 'br', 'swf', 'flv', 'woff', 'woff2')``

    File extensions to skip when compressing.

    Because the compression process will only create compressed files where
    this results in an actual size saving, it would be safe to leave this list
    empty and attempt to compress all files. However, for files which we're
    confident won't benefit from compression, it speeds up the process if we
    just skip over them.



.. attribute:: WHITENOISE_ADD_HEADERS_FUNCTION

    :default: ``None``

    Reference to a function which is passed the headers object for each static file,
    allowing it to modify them.

    For example: ::

        def force_download_pdfs(headers, path, url):
            if path.endswith('.pdf'):
                headers['Content-Disposition'] = 'attachment'

        WHITENOISE_ADD_HEADERS_FUNCTION = force_download_pdfs

    The function is passed:

    headers
      A `wsgiref.headers`__ instance (which you can treat just as a dict) containing
      the headers for the current file

    path
      The absolute path to the local file

    url
      The host-relative URL of the file e.g. ``/static/styles/app.css``

    The function should not return anything; changes should be made by modifying the
    headers dictionary directly.


.. attribute:: WHITENOISE_IMMUTABLE_FILE_TEST

    :default: See :file:`immutable_file_test <whitenoise/middleware.py#L121>` in source

    Reference to function, or string.

    If a reference to a function, this is passed the path and URL for each
    static file and should return whether that file is immutable, i.e.
    guaranteed not to change, and so can be safely cached forever. The default
    is designed to work with Django's ManifestStaticFilesStorage backend, and
    any derivatives of that, so you should only need to change this if you are
    using a different system for versioning your static files.

    If a string, this is treated as a regular expression and each file's URL is
    matched against it.

    Example: ::

        def immutable_file_test(path, url):
            # Match filename with 12 hex digits before the extension
            # e.g. app.db8f2edc0c8a.js
            return re.match(r'^.+\.[0-9a-f]{12}\..+$', url)

        WHITENOISE_IMMUTABLE_FILE_TEST = immutable_file_test

    The function is passed:

    path
      The absolute path to the local file

    url
      The host-relative URL of the file e.g. ``/static/styles/app.css``



.. attribute:: WHITENOISE_STATIC_PREFIX

    :default: Path component of ``settings.STATIC_URL`` (with
              ``settings.FORCE_SCRIPT_NAME`` removed if set)

    The URL prefix under which static files will be served.

    Usually this can be determined automatically by using the path component of
    ``STATIC_URL``. So if ``STATIC_URL`` is ``https://example.com/static/``
    then ``WHITENOISE_STATIC_PREFIX`` will be ``/static/``.

    If your application is not running at the root of the domain and
    ``FORCE_SCRIPT_NAME`` is set then this value will be removed from the
    ``STATIC_URL`` path first to give the correct prefix.

    If your deployment is more complicated than this (for instance, if you are
    using a CDN which is doing path rewriting) then you may need to configure
    this value directly.



.. attribute:: WHITENOISE_KEEP_ONLY_HASHED_FILES

    :default: ``False``

    Stores only files with hashed names in ``STATIC_ROOT``.

    By default, Django's hashed static files system creates two copies of each
    file in ``STATIC_ROOT``: one using the original name, e.g. ``app.js``, and
    one using the hashed name, e.g. ``app.db8f2edc0c8a.js``. If WhiteNoise's
    compression backend is being used this will create another two copies of
    each of these files (using Gzip and Brotli compression) resulting in six
    output files for each input file.

    In some deployment scenarios it can be important to reduce the size of the
    build artifact as much as possible.  This setting removes the "un-hashed"
    version of the file (which should be not be referenced in any case) which
    should reduce the space required for static files by half.

    Note, this setting is only effective if the WhiteNoise storage backend is
    being used.


.. attribute:: WHITENOISE_MANIFEST_STRICT

    :default: ``True``

    Set to ``False`` to prevent Django throwing an error if you reference a
    static file which doesn't exist.

    This works by setting the manifest_strict_ option on the underlying Django
    storage instance, as described in the Django documentation:

      If a file isn't found in the ``staticfiles.json`` manifest at runtime, a
      ``ValueError`` is raised. This behavior can be disabled by subclassing
      ``ManifestStaticFilesStorage`` and setting the ``manifest_strict`` attribute to
      ``False`` -- nonexistent paths will remain unchanged.

    Note, this setting is only effective if the WhiteNoise storage backend is
    being used.

Additional Notes

Django Compressor

For performance and security reasons WhiteNoise does not check for new files after startup (unless using Django DEBUG mode). As such, all static files must be generated in advance. If you're using Django Compressor, this can be performed using its offline compression feature.

Serving Media Files

WhiteNoise is not suitable for serving user-uploaded "media" files. For one thing, as described above, it only checks for static files at startup and so files added after the app starts won't be seen. More importantly though, serving user-uploaded files from the same domain as your main application is a security risk (this blog post from Google security describes the problem well). And in addition to that, using local disk to store and serve your user media makes it harder to scale your application across multiple machines.

For all these reasons, it's much better to store files on a separate dedicated storage service and serve them to users from there. The django-storages library provides many options e.g. Amazon S3, Azure Storage, and Rackspace CloudFiles.

How do I know it's working?

You can confirm that WhiteNoise is installed and configured correctly by running you application locally with DEBUG disabled and checking that your static files still load.

First you need to run collectstatic to get your files in the right place:

python manage.py collectstatic

Then make sure DEBUG is set to False in your settings.py and start the server:

python manage.py runserver

You should find that your static files are served, just as they would be in production.

Troubleshooting the WhiteNoise Storage backend

If you're having problems with the WhiteNoise storage backend, the chances are they're due to the underlying Django storage engine. This is because WhiteNoise only adds a thin wrapper around Django's storage to add compression support, and because the compression code is very simple it generally doesn't cause problems.

The most common issue is that there are CSS files which reference other files (usually images or fonts) which don't exist at that specified path. When Django attempts to rewrite these references it looks for the corresponding file and throws an error if it can't find it.

To test whether the problems are due to WhiteNoise or not, try swapping the WhiteNoise storage backend for the Django one:

STATICFILES_STORAGE = 'django.contrib.staticfiles.storage.ManifestStaticFilesStorage'

If the problems persist then your issue is with Django itself (try the docs or the mailing list). If the problem only occurs with WhiteNoise then raise a ticket on the issue tracker.

Restricting CloudFront to static files

The instructions for setting up CloudFront given above will result in the entire site being accessible via the CloudFront URL. It's possible that this can cause SEO problems if these URLs start showing up in search results. You can restrict CloudFront to only proxy your static files by following these directions:

  1. Go to your newly created distribution and click "Distribution Settings", then the "Behaviors" tab, then "Create Behavior". Put static/* into the path pattern and click "Create" to save.
  2. Now select the Default (*) behaviour and click "Edit". Set "Restrict Viewer Access" to "Yes" and then click "Yes, Edit" to save.
  3. Check that the static/* pattern is first on the list, and the default one is second. This will ensure that requests for static files are passed through but all others are blocked.

Using other storage backends

WhiteNoise will only work with storage backends that stores their files on the local filesystem in STATIC_ROOT. It will not work with backends that store files remotely, for instance on Amazon S3.

WhiteNoise makes my tests run slow!

WhiteNoise is designed to do as much work as possible upfront when the application starts so that it can serve files as efficiently as possible while the application is running. This makes sense for long-running production processes, but you might find that the added startup time is a problem during test runs when application instances are frequently being created and destroyed.

The simplest way to fix this is to make sure that during testing the WHITENOISE_AUTOREFRESH setting is set to True. (By default it is True when DEBUG is enabled and False otherwise.) This stops WhiteNoise from scanning your static files on start up but other than that its behaviour should be exactly the same.

It is also worth making sure you don't have unnecessary files in your STATIC_ROOT directory. In particular, be careful not to include a node_modules directory which can contain a very large number of files and significantly slow down your application startup. If you need to include specific files from node_modules then you can create symlinks from within your static directory to just the files you need.

Why do I get "ValueError: Missing staticfiles manifest entry for ..."?

If you are seeing this error that you means you are referencing a static file in your templates (using something like {% static "foo" %} which doesn't exist, or at least isn't where Django expects it to be. If you don't understand why Django can't find the file you can use

python manage.py findstatic --verbosity 2 foo

which will show you all the paths which Django searches for the file "foo".

If, for some reason, you want Django to silently ignore such errors you can set WHITENOISE_MANIFEST_STRICT to False.

Using WhiteNoise with Webpack / Browserify / $LATEST_JS_THING

A simple technique for integrating any frontend build system with Django is to use a directory layout like this:

./static_src
        ↓
  $ ./node_modules/.bin/webpack
        ↓
./static_build
        ↓
  $ ./manage.py collectstatic
        ↓
./static_root

Here static_src contains all the source files (JS, CSS, etc) for your project. Your build tool (which can be Webpack, Browserify or whatever you choose) then processes these files and writes the output into static_build.

The path to the static_build directory is added to settings.py:

STATICFILES_DIRS = [
   BASE_DIR / 'static_build'
]

This means that Django can find the processed files, but doesn't need to know anything about the tool which produced them.

The final manage.py collectstatic step writes "hash-versioned" and compressed copies of the static files into static_root ready for production.

Note, both the static_build and static_root directories should be excluded from version control (e.g. through .gitignore) and only the static_src directory should be checked in.

Deploying an application which is not at the root of the domain

Sometimes Django apps are deployed at a particular prefix (or "subdirectory") on a domain e.g. http://example.com/my-app/ rather than just http://example.com.

In this case you would normally use Django's FORCE_SCRIPT_NAME setting to tell the application where it is located. You would also need to ensure that STATIC_URL uses the correct prefix as well. For example:

FORCE_SCRIPT_NAME = '/my-app'
STATIC_URL = FORCE_SCRIPT_NAME + '/static/'

If you have set these two values then WhiteNoise will automatically configure itself correctly. If you are doing something more complex you may need to set :any:`WHITENOISE_STATIC_PREFIX` explicitly yourself.