webrtc-application-screen-share

Capture the users screen, application, audio or video and share over a WebRTC PeerConnection. This simple demo consists of a presenter who shares their screen or applications and an attendee who views that share video on a web page or a Chrome extension. The attendee can be either a Chrome extension or Firefox browser. The presenter must be using the Chrome extension. So right now this is a two user demo, one presentor and one attendee only.

This repo has three pieces.

1. Chrome packaged app to share screen or applications and audio\video. Packaged app can be used by two Chrome browsers presentor will be the peer who shares first.
2. Server application using node.js and web socket to relay messages between peers.
3. Attendee: Web page that receives and displays the shared video stream and also sends and receives audio and video (Chrome or Firefox).

• Presenter and Attendee packaged apps only work using Google Chrome, (Stable, Canary or Chromium).
• No need for a Web Server, it uses node.js which does both the WebRTC signaling and serves up the attendee web page (index.html).

screen or application capture uses getUserMedia API and chrome.desktopCapture

function onAccessApproved(id) {
  if (!id) {
    console.log("Access rejected");
    return;
  }
  navigator.webkitGetUserMedia({                                                                                                                                                                                                              
      audio: false,
      video: { mandatory: { chromeMediaSource: "desktop",
                            chromeMediaSourceId: id, 
                            maxWidth: screen.width,
                            maxHeight: screen.height,
                            minFrameRate: 1,
                            maxFrameRate: 5 }}
  }, gotStream, getUserMediaError);
}

document.querySelector('#share').addEventListener('click', function(e) {
  pending_request_id = chrome.desktopCapture.chooseDesktopMedia(
      ["screen", "window"], onAccessApproved);
});

Setup prerequesites

• Install Node.js and websocket (sudo npm install websocket)

Server Steps (Tested on Linux, MacOS and Windows)

• Clone this repo to your machine, does not need to be to a web server.
• Generate keys unless you have real ones, run these commands in the same folder as app.js (find equivalant commands for Windows or Linux these are for mac).
  • openssl genrsa -out webrtcwwsocket-key.pem 1024
  • openssl req -new -key webrtcwwsocket-key.pem -out webrtcwwsocket-csr.pem
  • openssl x509 -req -in webrtcwwsocket-csr.pem -signkey webrtcwwsocket-key.pem -out webrtcwwsocket-cert.pem
• Edit packaged_app/app.js (insert this machines ip address for WebSocket connection). Or use configure button when running the extension.
• run 'sudo node app.js'

Client Packaged App steps (Chrome browser or Chromebook)

• Install packaged app in chrome
• i.e. open 'chrome://extensions'
• click 'Developer Mode' check box.
• Click button 'Load unpacked extension'
• Navigate to the packaged_app folder of this repo.
• Launch app by clicking 'launch' link in chrome://extensions
• Or use Chrome App Launcher to launch it.
• If you get wss errors you may need to load the cert in a Crome browser tab first by clicking on https://<your node.js ip address> and accepting the cert.

Client Attendee Web Page Steps

• Start Chrome or Firefox browser.
• Point browser to e.g. https://<your node.js ip address>
• Accept the self signed cert in which ever way the browser allows.
• You can test this on the same machine or across the network over two machines.