https://github.com/mmzeeman/elli_websocket

Elli Websocket Handler
https://github.com/mmzeeman/elli_websocket

Last synced: 17 days ago
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Elli Websocket Handler

• Host: GitHub
• URL: https://github.com/mmzeeman/elli_websocket
• Owner: mmzeeman
• License: apache-2.0
• Created: 2013-11-02T22:43:28.000Z (about 11 years ago)
• Default Branch: master
• Last Pushed: 2019-05-07T11:54:55.000Z (over 5 years ago)
• Last Synced: 2024-10-12T04:31:37.429Z (about 1 month ago)
• Language: Erlang
• Size: 35.2 KB
• Stars: 19
• Watchers: 5
• Forks: 20
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
Elli Websocket Handler

======================

elli_websocket is a websocket handler for Elli: https://github.com/knutin/elli

## Installation

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.

```erlang

% 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:

```sh

$ ./rebar get-deps

$ ./rebar compile

```

## Callback module

See elli_example_websocket.erl for details.

```erlang

-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.

```

## Upgrading to Websocket Connection

This is an example of how you can upgrade to a websocket connection.

```erlang

-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.

```