Draw: demo of realtime sharing drawing board

Background

open whiteboard is a drawing websocket javascript application, you can find more information on the given link.

https://developer.mozilla.org/fr/demosdetail/open-whiteboard

draw was first made as a demo on the ChicagoBoss framework, to show how you could handle websocket inside ChicagoBoss, since then i have made naga-framework

Install erlang/OTP

• install from source code using kerl

 $ cd ~
 $ mkdir bin
 $ cd bin
 $ curl -O https://raw.githubusercontent.com/kerl/kerl/master/kerl
 $ chmod u+x kerl
 $ kerl list releases
 $ kerl build 19.2 19.2
 $ kerl install 19.2 ~/kerl/19.2
 $ .  ~/kerl/19.2/activate

Quickstart

Get draw

    >git clone http://github.com/naga-framework/draw.git
    >cd draw
    >./mad deps comp plan repl

All Features in One snippet

-module(index).
-export([index/3, event/1]).
-default_action(index).
-actions([index]).

-include_lib("n2o/include/wf.hrl").
-include_lib("nitro/include/nitro.hrl").

-define(TOPIC, {topic,<<"drawboard">>}).

%% INDEX CONTROLLER
index(<<"GET">>, _, _) -> ok.

%% WS EVENT HANDLING
event(init)                     -> wf:reg(?TOPIC);
event(#client{data={Sid,Data}}) -> case wf:session_id() of Sid -> skip; _-> draw(Data) end;
event(#client{data=D})          -> wf:send(?TOPIC,#client{data={wf:session_id(),D}}).

draw(Data) -> 
  Exec = wf:f("var dt = ~s;if(dt.socketid !== -1)"
              "{mySocketId =dt.socketid;} else "
              "{setupDraw(dt, true);}",[Data]),
  wf:wire(Exec).

Open http://localhost:8001/ in your browser, open a second web browser on the same url, or a tab in the first browser then start to draw. :)