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CoreWebSocket - Core Foundation based WebSocket Library for iOS/OSX

CoreWebSocket is an C language, Core Foundation based library for iOS and Mac OSX. It can be used from Objective-C.

WebSocket enables low latency, bi-directional, full-duplex communication channel over TCP with web browser. It works with all modern web browsers including Safari, Chrome, Firefox and Opera. It works with iOS Safari as well.

Installation

To get the library using git in your project:

git submodule add git://github.com/mirek/CoreWebSocket.git CoreWebSocket

Then to add the library to your project

Add CoreWebSocket.xcodeproj to project
In to targets Build Phases
1. In Target Dependencies add
  - CoreWebSocket
2. In Link Binary With Libraries add
  - CFNetwork.framework
  - CoreServices.framework
  - libcrypto.dylib
  - CoreWebSocket.framework
3. Add Build Phase > Add Copy Files
  1. Set Destination to be Frameworks
  2. Add CoreWebSocket.framework
Clean
Build CoreWebSocket
Build your app

Usage

Exmaple AppDelegate.m

#import "AppDelegate.h"
#include "CoreWebSocket/CoreWebSocket.h"

@implementation AppDelegate

void Callback(WebSocketRef self, WebSocketClientRef client, CFStringRef value) {
    if (value) {
        CFShow(value);
    }
}

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
    WebSocketRef webSocket = WebSocketCreateWithHostAndPort(NULL, kWebSocketHostAny, 6001, NULL);
    if (webSocket) {
        webSocket->callbacks.didClientReadCallback = Callback;
    }
}

@end

Web Browser Usage

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-type" content="text/html; charset=utf-8">
    <script type="text/javascript" charset="utf-8">

      // WebSocket
      var ws = null;

      // When the page is loaded...
      window.addEventListener('load', function(e) {

        // Check if the browser supports WebSockets...
        if ("WebSocket" in window) {
  
          // ...it does, let's connect to localhost default port.
          // Make sure Quartz Composer composition is running with
          // the WebSocket Patch set to port 60001. 
          ws = new WebSocket('ws://localhost:60001');
    
          // Invoked when there was an error with the connection. 
          ws.onerror = function(e) {
            console.log('error', e);
          }
    
          // Invoked when the socket has been opened successfully.
          ws.onopen = function(e) {
            console.log('open', e);
          }
    
          // Callback invoked when incoming messages arrive. Event `data` attribute
          // holds the string passed. WebSocket in current spec supports utf8 text-based
          // communication only. Binary data  is base64 encoded.
          ws.onmessage = function(e) {
            var json = JSON.parse(e.data);
            console.log('message', json);
          }
    
          // Invoked when the socket has been closed
          ws.onclose = function(e) {
            console.log('close', e);
          }
    
        } else {
  
          // ...seems like the web browser doesn't support WebSockets.
          alert('WebSocket not supported by your browser, use Safari, Chrome or Firefox');
    
        }
      }, false);

    </script>
  </head>
</html>

License

Unless otherwise stated, the code is released under Open Source MIT License, (c) Copyright Mirek Rusin <mirek [at] me [dot] com>

Parts of the source code (particularly Base64 encoding functions) have been copied from http://opensource.apple.com which are released under Apple Public Source License 2.0 http://www.opensource.apple.com/apsl.

Portions of the copied source code could be modified.