django-cors-headers
django-cors-headers is a Django application for handling the server headers required for Cross-Origin Resource Sharing (CORS).
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Description
===================
django-cors-headers
===================
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A Django App that adds Cross-Origin Resource Sharing (CORS) headers to
responses. This allows in-browser requests to your Django application from
other origins.
----
**Improve your Django and Git skills** with `my books <https://adamj.eu/books/>`__.
----
About CORS
----------
Adding CORS headers allows your resources to be accessed on other domains. It's
important you understand the implications before adding the headers, since you
could be unintentionally opening up your site's private data to others.
Some good resources to read on the subject are:
* Julia Evans' `introductory comic <https://drawings.jvns.ca/cors/>`__ and
`educational quiz <https://questions.wizardzines.com/cors.html>`__.
* Jake Archibald’s `How to win at CORS <https://jakearchibald.com/2021/cors/>`__
* The `MDN Article <https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS>`_
* The `web.dev Article <https://web.dev/articles/cross-origin-resource-sharing>`_
* The `Wikipedia Page <https://en.wikipedia.org/wiki/Cross-origin_resource_sharing>`_
Requirements
------------
Python 3.9 to 3.14 supported.
Django 4.2 to 6.0 supported.
Setup
-----
Install from **pip**:
.. code-block:: sh
python -m pip install django-cors-headers
and then add it to your installed apps:
.. code-block:: python
INSTALLED_APPS = [
...,
"corsheaders",
...,
]
Make sure you add the trailing comma or you might get a ``ModuleNotFoundError``
(see `this blog
post <https://adamj.eu/tech/2020/06/29/why-does-python-raise-modulenotfounderror-when-modifying-installed-apps/>`__).
You will also need to add a middleware class to listen in on responses:
.. code-block:: python
MIDDLEWARE = [
...,
"corsheaders.middleware.CorsMiddleware",
"django.middleware.common.CommonMiddleware",
...,
]
``CorsMiddleware`` should be placed as high as possible, especially before any
middleware that can generate responses such as Django's ``CommonMiddleware`` or
Whitenoise's ``WhiteNoiseMiddleware``. If it is not before, it will not be able
to add the CORS headers to these responses.
About
-----
**django-cors-headers** was created in January 2013 by Otto Yiu. It went
unmaintained from August 2015 and was forked in January 2016 to the package
`django-cors-middleware <https://github.com/zestedesavoir/django-cors-middleware>`_
by Laville Augustin at Zeste de Savoir.
In September 2016, Adam Johnson, Ed Morley, and others gained maintenance
responsibility for **django-cors-headers**
(`Issue 110 <https://github.com/adamchainz/django-cors-headers/issues/110>`__)
from Otto Yiu.
Basically all of the changes in the forked **django-cors-middleware** were
merged back, or re-implemented in a different way, so it should be possible to
switch back. If there's a feature that hasn't been merged, please open an issue
about it.
**django-cors-headers** has had `40+ contributors
<https://github.com/adamchainz/django-cors-headers/graphs/contributors>`__
in its time; thanks to every one of them.
Configuration
-------------
Configure the middleware's behaviour in your Django settings. You must set at
least one of three following settings:
* ``CORS_ALLOWED_ORIGINS``
* ``CORS_ALLOWED_ORIGIN_REGEXES``
* ``CORS_ALLOW_ALL_ORIGINS``
``CORS_ALLOWED_ORIGINS: Sequence[str]``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A list of origins that are authorized to make cross-site HTTP requests.
The origins in this setting will be allowed, and the requesting origin will be echoed back to the client in the |access-control-allow-origin header|__.
Defaults to ``[]``.
.. |access-control-allow-origin header| replace:: ``access-control-allow-origin`` header
__ https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Origin
An Origin is defined by `the CORS RFC Section 3.2 <https://tools.ietf.org/html/rfc6454#section-3.2>`_ as a URI scheme + hostname + port, or one of the special values ``'null'`` or ``'file://'``.
Default ports (HTTPS = 443, HTTP = 80) are optional.
The special value ``null`` is sent by the browser in `"privacy-sensitive contexts" <https://tools.ietf.org/html/rfc6454#section-6>`__, such as when the client is running from a ``file://`` domain.
The special value `file://` is sent accidentally by some versions of Chrome on Android as per `this bug <https://bugs.chromium.org/p/chromium/issues/detail?id=991107>`__.
Example:
.. code-block:: python
CORS_ALLOWED_ORIGINS = [
"https://example.com",
"https://sub.example.com",
"http://localhost:8080",
"http://127.0.0.1:9000",
]
Previously this setting was called ``CORS_ORIGIN_WHITELIST``, which still works as an alias, with the new name taking precedence.
``CORS_ALLOWED_ORIGIN_REGEXES: Sequence[str | Pattern[str]]``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A list of strings representing regexes that match Origins that are authorized to make cross-site HTTP requests.
Defaults to ``[]``.
Useful when ``CORS_ALLOWED_ORIGINS`` is impractical, such as when you have a large number of subdomains.
Example:
.. code-block:: python
CORS_ALLOWED_ORIGIN_REGEXES = [
r"^https://\w+\.example\.com$",
]
Previously this setting was called ``CORS_ORIGIN_REGEX_WHITELIST``, which still works as an alias, with the new name taking precedence.
``CORS_ALLOW_ALL_ORIGINS: bool``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If ``True``, all origins will be allowed.
Other settings restricting allowed origins will be ignored.
Defaults to ``False``.
Setting this to ``True`` can be *dangerous*, as it allows any website to make cross-origin requests to yours.
Generally you'll want to restrict the list of allowed origins with ``CORS_ALLOWED_ORIGINS`` or ``CORS_ALLOWED_ORIGIN_REGEXES``.
Previously this setting was called ``CORS_ORIGIN_ALLOW_ALL``, which still works as an alias, with the new name taking precedence.
--------------
The following are optional settings, for which the defaults probably suffice.
``CORS_URLS_REGEX: str | Pattern[str]``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A regex which restricts the URL's for which the CORS headers will be sent.
Defaults to ``r'^.*$'``, i.e. match all URL's.
Useful when you only need CORS on a part of your site, e.g. an API at ``/api/``.
Example:
.. code-block:: python
CORS_URLS_REGEX = r"^/api/.*$"
``CORS_ALLOW_METHODS: Sequence[str]``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A list of HTTP verbs that are allowed for the actual request.
Defaults to:
.. code-block:: python
CORS_ALLOW_METHODS = (
"DELETE",
"GET",
"OPTIONS",
"PATCH",
"POST",
"PUT",
)
The default can be imported as ``corsheaders.defaults.default_methods`` so you can just extend it with your custom methods.
This allows you to keep up to date with any future changes.
For example:
.. code-block:: python
from corsheaders.defaults import default_methods
CORS_ALLOW_METHODS = (
*default_methods,
"POKE",
)
``CORS_ALLOW_HEADERS: Sequence[str]``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The list of non-standard HTTP headers that you permit in requests from the browser.
Sets the |Access-Control-Allow-Headers header|__ in responses to `preflight requests <https://developer.mozilla.org/en-US/docs/Glossary/Preflight_request>`__.
Defaults to:
.. |Access-Control-Allow-Headers header| replace:: ``Access-Control-Allow-Headers`` header
__ https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Headers
.. code-block:: python
CORS_ALLOW_HEADERS = (
"accept",
"authorization",
"content-type",
"user-agent",
"x-csrftoken",
"x-requested-with",
)
The default can be imported as ``corsheaders.defaults.default_headers`` so you can extend it with your custom headers.
This allows you to keep up to date with any future changes.
For example:
.. code-block:: python
from corsheaders.defaults import default_headers
CORS_ALLOW_HEADERS = (
*default_headers,
"my-custom-header",
)
``CORS_EXPOSE_HEADERS: Sequence[str]``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The list of extra HTTP headers to expose to the browser, in addition to the default `safelisted headers <https://developer.mozilla.org/en-US/docs/Glossary/CORS-safelisted_response_header>`__.
If non-empty, these are declared in the |access-control-expose-headers header|__.
Defaults to ``[]``.
.. |access-control-expose-headers header| replace:: ``access-control-expose-headers`` header
__ https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Expose-Headers
``CORS_PREFLIGHT_MAX_AGE: int``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The number of seconds the browser can cache the preflight response.
This sets the |access-control-max-age header|__ in preflight responses.
If this is 0 (or any falsey value), no max age header will be sent.
Defaults to ``86400`` (one day).
.. |access-control-max-age header| replace:: ``access-control-max-age`` header
__ https://developer.mozilla.org/en-U