daphne

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Daphne is a HTTP, HTTP2 and WebSocket protocol server for
ASGI <https://github.com/django/asgiref/blob/main/specs/asgi.rst>_ and
ASGI-HTTP <https://github.com/django/asgiref/blob/main/specs/www.rst>_,
developed to power Django Channels.

It supports automatic negotiation of protocols; there’s no need for URL
prefixing to determine WebSocket endpoints versus HTTP endpoints.

Running

Simply point Daphne to your ASGI application, and optionally
set a bind address and port (defaults to localhost, port 8000)::

daphne -b 0.0.0.0 -p 8001 django_project.asgi:application

If you intend to run daphne behind a proxy server you can use UNIX
sockets to communicate between the two::

daphne -u /tmp/daphne.sock django_project.asgi:application

If daphne is being run inside a process manager, you might
want it to bind to a file descriptor passed down from a parent process.
To achieve this you can use the --fd flag::

daphne --fd 5 django_project.asgi:application

If you want more control over the port/socket bindings you can fall back to
using twisted's endpoint description strings <http://twistedmatrix.com/documents/current/api/twisted.internet.endpoints.html#serverFromString>_
by using the --endpoint (-e) flag, which can be used multiple times.
This line would start a SSL server on port 443, assuming that key.pem and crt.pem
exist in the current directory (requires pyopenssl to be installed)::

daphne -e ssl:443:privateKey=key.pem:certKey=crt.pem django_project.asgi:application

Endpoints even let you use the txacme endpoint syntax to get automatic certificates
from Let’s Encrypt, which you can read more about at http://txacme.readthedocs.io/en/stable/.

To see all available command line options run daphne with the -h flag.

HTTP/2 Support

Daphne supports terminating HTTP/2 connections natively. You’ll
need to do a couple of things to get it working, though. First, you need to
make sure you install the Twisted http2 and tls extras::

pip install -U "Twisted[tls,http2]"

Next, because all current browsers only support HTTP/2 when using TLS, you will
need to start Daphne with TLS turned on, which can be done using the Twisted endpoint syntax::

daphne -e ssl:443:privateKey=key.pem:certKey=crt.pem django_project.asgi:application

Alternatively, you can use the txacme endpoint syntax or anything else that
enables TLS under the hood.

You will also need to be on a system that has OpenSSL 1.0.2 or greater; if you are
using Ubuntu, this means you need at least Ubuntu 16.04.

Now, when you start up Daphne, it should tell you this in the log::

2017-03-18 19:14:02,741 INFO     Starting server at ssl:port=8000:privateKey=privkey.pem:certKey=cert.pem, channel layer django_project.asgi:channel_layer.
2017-03-18 19:14:02,742 INFO     HTTP/2 support enabled

Then, connect with a browser that supports HTTP/2, and everything should be
working. It’s often hard to tell that HTTP/2 is working, as the log Daphne gives you
will be identical (it’s HTTP, after all), and most browsers don’t make it obvious
in their network inspector windows. There are browser extensions that will let
you know clearly if it’s working or not.

Daphne only supports “normal” requests over HTTP/2 at this time; there is not
yet support for extended features like Server Push. It will, however, result in
much faster connections and lower overheads.

If you have a reverse proxy in front of your site to serve static files or
similar, HTTP/2 will only work if that proxy understands and passes through the
connection correctly.

Root Path (SCRIPT_NAME)

In order to set the root path for Daphne, which is the equivalent of the
WSGI SCRIPT_NAME setting, you have two options:

• Pass a header value Daphne-Root-Path, with the desired root path as a
  URLencoded ASCII value. This header will not be passed down to applications.

• Set the --root-path commandline option with the desired root path as a
  URLencoded ASCII value.

The header takes precedence if both are set. As with SCRIPT_ALIAS, the value
should start with a slash, but not end with one; for example::

daphne --root-path=/forum django_project.asgi:application

Python Support

Daphne requires Python 3.9 or later.

Contributing

Please refer to the
main Channels contributing docs <https://github.com/django/channels/blob/main/CONTRIBUTING.rst>_.

To run tests, make sure you have installed the tests extra with the package::

cd daphne/
pip install -e '.[tests]'
pytest

Maintenance and Security

To report security issues, please contact [email protected]. For GPG
signatures and more security process information, see
https://docs.djangoproject.com/en/dev/internals/security/.

To report bugs or request new features, please open a new GitHub issue.

This repository is part of the Channels project. For the shepherd and maintenance team, please see the
main Channels readme <https://github.com/django/channels/blob/main/README.rst>_.