elli_websocket is a websocket handler for Elli: https://github.com/knutin/elli
You can add elli_websocket to your application by adding it as a dependency to your elli application. At the moment elli_websocket is dependant on a handover and ssl feature and needs a specific elli branch.
% rebar.config
{deps, [
{elli, ".*", {git, "git://github.com/mmzeeman/elli.git", {branch, "ssl+handover"}}},
{elli_websocket, ".*", {git, "git://github.com/mmzeeman/elli_websocket.git", {branch, "master"}}},
% ...
]}.Afterwards you can run:
$ ./rebar get-deps
$ ./rebar compileSee elli_example_websocket.erl for details.
-module(elli_echo_websocket_handler).
-export([websocket_init/1, websocket_handle/3, websocket_info/3, websocket_handle_event/3]).
websocket_init(Req, Opts) ->
State = undefined,
{ok, [], State}.
websocket_handle(_Req, {text, Data}, State) ->
{reply, {text, Data}, State};
websocket_handle(_Req, {binary, Data}, State) ->
{reply, {binary, Data}, State};
websocket_handle(_Req, _Frame, State) ->
{ok, State}.
websocket_info(Req, Message, State) ->
{ok, State}.
websocket_handle_event(Name, EventArgs, State) ->
ok.
This is an example of how you can upgrade to a websocket connection.
-module(elli_echo_websocket).
-export([init/2, handle/2, handle_event/3]).
-include_lib("elli/include/elli.hrl").
-behaviour(elli_handler).
init(Req, Args) ->
Method = case elli_request:get_header(<<"Upgrade">>, Req) of
<<"websocket">> ->
init_ws(elli_request:path(Req), Req, Args);
_ ->
ignore
end.
handle(Req, Args) ->
Method = case elli_request:get_header(<<"Upgrade">>, Req) of
<<"websocket">> ->
websocket;
_ ->
elli_request:method(Req)
end,
handle(Method, elli_request:path(Req), Req, Args).
handle_event(_Event, _Data, _Args) ->
ok.
%%
%% Helpers
%%
init_ws([<<"echo_websocket">>], _Req, _Args) ->
{ok, handover};
init_ws(_, _, _) ->
ignore.
handle('websocket', [<<"echo_websocket">>], Req, Args) ->
%% Upgrade to a websocket connection.
elli_websocket:upgrade(Req, Args),
%% websocket is closed.
{close, <<>>};
handle('GET', [<<"echo_websocket">>], _Req, _Args) ->
%% We got a normal request, request was not upgraded.
{200, [], <<"Use an upgrade request">>};
handle(_,_,_,_) ->
ignore.