daphne

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 3.8 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 [e-mail]. 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>_.