mirror of
https://github.com/ninenines/cowboy.git
synced 2025-07-14 12:20:24 +00:00
a45813c60f
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.
26 lines
685 B
Erlang
26 lines
685 B
Erlang
%% This module implements a loop handler for long-polling.
|
|
%% It starts by sending itself a message after 200ms,
|
|
%% then sends another after that for a total of 3 messages.
|
|
%% When it receives the last message, it sends a 102 reply back.
|
|
|
|
-module(long_polling_h).
|
|
|
|
-export([init/2]).
|
|
-export([info/3]).
|
|
-export([terminate/3]).
|
|
|
|
init(Req, _) ->
|
|
erlang:send_after(200, self(), timeout),
|
|
{cowboy_loop, Req, 2, hibernate}.
|
|
|
|
info(timeout, Req, 0) ->
|
|
%% @todo Why 102?
|
|
{stop, cowboy_req:reply(102, Req), 0};
|
|
info(timeout, Req, Count) ->
|
|
erlang:send_after(200, self(), timeout),
|
|
{ok, Req, Count - 1, hibernate}.
|
|
|
|
terminate(stop, _, 0) ->
|
|
ok;
|
|
terminate({error, overflow}, _, _) ->
|
|
ok.
|