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cowboy/examples/eventsource
Loïc Hoguin a45813c60f
Allow passing options to sub protocols
Before this commit we had an issue where configuring a
Websocket connection was simply not possible without
doing magic, adding callbacks or extra return values.
The init/2 function only allowed setting hibernate
and timeout options.

After this commit, when switching to a different
type of handler you can either return

  {module, Req, State}

or

  {module, Req, State, Opts}

where Opts is any value (as far as the sub protocol
interface is concerned) and is ultimately checked
by the custom handlers.

A large protocol like Websocket would accept only
a map there, with many different options, while a
small interface like loop handlers would allow
passing hibernate and nothing else.

For Websocket, hibernate must be set from the
websocket_init/1 callback, because init/2 executes
in a separate process.

Sub protocols now have two callbacks: one with the
Opts value, one without.

The loop handler code was largely reworked and
simplified. It does not need to manage a timeout
or read from the socket anymore, it's the job of
the protocol code. A lot of unnecessary stuff was
therefore removed.

Websocket compression must now be enabled from
the handler options instead of per listener. This
means that a project can have two separate Websocket
handlers with different options. Compression is
still disabled by default, and the idle_timeout
value was changed from inifnity to 60000 (60 seconds),
as that's safer and is also a good value for mobile
devices.
2017-02-18 18:26:20 +01:00
..
priv Add EventSource example 2013-02-16 02:26:32 -06:00
src Allow passing options to sub protocols 2017-02-18 18:26:20 +01:00
Makefile Simplify specifying the Cowboy version in examples 2016-01-14 22:58:22 +01:00
README.asciidoc Simplify example instructions and fix broken examples 2016-01-14 20:00:50 +01:00
relx.config Convert the EventSource example to a release 2013-09-08 11:48:48 +02:00

= EventSource example

To try this example, you need GNU `make` and `git` in your PATH.

To build and run the example, use the following command:

[source,bash]
$ make run

Then point your browser to http://localhost:8080