WebSockets TrafficScript library

README.md

This Riverbed TrafficScript library implements support for identification and modification of WebSockets traffic in Stingray Traffic Manager.

For more details and usage instructions, check out https://splash.riverbed.com/docs/DOC-1451

Tags: #Stingray #TrafficScript #WebSockets #splash.riverbed.com

libWebSockets.rts

# WebSockets protocol library
# 7 Feb 2013
# 
# This library is not supported by Riverbed Technology (or by me).
# For community support, refer to splash.riverbed.com
# 
# Capabilities:
# 
#    isWS():  returns true if current connection is a websockets 
#       request, and false if not (for example, is HTTP)
#    getMethod(), getPath(), getRawURL(), getVersion(), 
#    getHeader( headername ): retrieve values from websocket client 
#       handshake
#    setMethod(), setPath(), setVersion(), 
#    setHeader( headername, headervalue ): set values in websocket
#       client handshake
# 
# Usage:
# 
# Import library into TrafficScript rule as follows:
# 
#    import WebSockets as ws;
# 
# Use library functions as follows:
# 
#    if( !ws.isWS() ) pool.use( "web servers loopback" );
# 
#    $hh = ws.getHeader( "Host" );
#    if( $hh == "echo.site.com" ) {
#       ws.setPath( "/echo" );
#       pool.use( "Echo servers" );
#    }
# 
# Assign the rules to a 'Generic Streaming' virtual server type, and 
# arrange that the rules run at request processing, and only 'run once'.


sub isWS() {
   if( !connection.data.get( "ws-init" ) ) initRequest();
   return (getHeader( "Connection" ) == "Upgrade" && getHeader( "Upgrade" ) == "websocket" );
}

sub getMethod() {
   if( !connection.data.get( "ws-init" ) ) initRequest();
   return connection.data.get( "ws-METHOD" );
}

sub getPath() {
   if( !connection.data.get( "ws-init" ) ) initRequest();
   return connection.data.get( "ws-PATH" );
}

sub getRawURL() {
   if( !connection.data.get( "ws-init" ) ) initRequest();
   return connection.data.get( "ws-RAWURL" );
}

sub getVersion() {
   if( !connection.data.get( "ws-init" ) ) initRequest();
   return connection.data.get( "ws-VERSION" );
}

sub getTerminator() {
   if( !connection.data.get( "ws-init" ) ) initRequest();
   return connection.data.get( "ws-TERMINATOR" );
}

sub getHeaders() {
   if( !connection.data.get( "ws-init" ) ) initRequest();
   return connection.data.get( "ws-HEADERS" );
}

sub getHeader( $h ) {
   $t = getTerminator();
   $hh = getHeaders();
   string.regexMatch( $hh, $t.$h.':\s+(.*?)'.$t, "i" ); 
   return $1;
}

sub setMethod( $method ) {
   if( !connection.data.get( "ws-init" ) ) initRequest();
   connection.data.set( "ws-METHOD", $method );
   updateRequest();
}

sub setPath( $path ) {
   if( !connection.data.get( "ws-init" ) ) initRequest();
   connection.data.set( "ws-RAWURL", escape( $path ) );
   connection.data.set( "ws-PATH", $path );
   updateRequest();
}

sub setVersion( $version ) {
   if( !connection.data.get( "ws-init" ) ) initRequest();
   connection.data.set( "ws-VERSION", $version );
   updateRequest();
}

sub setHeader( $h, $v ) {
   if( !connection.data.get( "ws-init" ) ) initRequest();

   $t = getTerminator();
   $hh = getHeaders();
   $hh2 = string.regexsub( $hh, $t.$h.':\s+.*?'.$t, $t.$h.': '.$v.$t );
   if( $hh2 == $hh ) $hh2 = $t.$h.': '.$v.$hh;
   connection.data.set( "ws-HEADERS", $hh2 ); 
   updateRequest();
}

sub initRequest() {
   $first = request.getLine();
   
   $t = "\n";
   if( endsWith( $first, "\r\n" ) ) $t = "\r\n";
   connection.data.set( "ws-TERMINATOR", $t );

   # Split the request to only get headers on the 1st request
   request.endsWith( $t.$t );

   # Headers are prefixed by a terminator to make searches easier, and 
   # end with the double-terminator
   $headers = request.getLine( $t.$t, $1-length( $t ) );
 
   # Parse the first line (best effort):
   string.regexmatch( $first, '([^\s]+)\s(.+)\s(HTTP.*?)\s', "i" );
   connection.data.set( "ws-METHOD", $1 );
   connection.data.set( "ws-RAWURL", string.trim( $2 ) );
   connection.data.set( "ws-PATH", string.unescape( string.trim( $2 ) ) );
   connection.data.set( "ws-VERSION", $3 );
   connection.data.set( "ws-HEADERS", $headers );
   
   connection.data.set( "ws-init", 1 );
}

sub updateRequest() {
   request.set( connection.data.get( "ws-METHOD" ) . " " . 
      connection.data.get( "ws-RAWURL" )  . " " . 
      connection.data.get( "ws-VERSION" ) . 
      connection.data.get( "ws-HEADERS" )  );
}

testclient.html

<!DOCTYPE html>  
<html>  
<head>  
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>  
<title>WebSockets Client</title>  
</head>  
<body>

<script language="javascript" type="text/javascript"> 

var websocket;

function init() { 
    $('#connect').click(function(){  
        doConnect();  
    }); 
    
    $('#send').click(function() { 
        doSend( $('#text').val() );
    });   

    $('#disconnect').click(function(){  
        websocket.close();  
    }); 
}

function doConnect() {
    websocket = new WebSocket( $('#server').val() ); 
    
    websocket.onopen = function( e ) { 
        writeToScreen("CONNECTED to " + websocket.url); 
    }; 
    websocket.onclose = function( e ) { 
        writeToScreen("DISCONNECTED from " + websocket.url); 
    }; 
    websocket.onmessage = function( e ) { 
        writeToScreen('<span style="color: blue;">&lt;--: ' + e.data + '</span>'); 
    }; 
    websocket.onerror = function( e ) { 
        writeToScreen('<span style="color: red;">ERROR:</span> ' + e.data);
    }; 
}

function doSend(message) {
   writeToScreen("--&gt;: " + message);  websocket.send(message);
}  

function writeToScreen(message) { 
   var pre = document.createElement("div"); 
   pre.innerHTML = message; 
   $('#output').append(pre);
}

$(document).ready( init );
</script>  

<h2>WebSocket Test</h2>  

<!-- sample servers:
   ws://echo.websocket.org/
   wss://echo.websocket.org/
   ws://ajf.me:8080/
   -->
   
<input id="server" type="text" value="ws://echo.websocket.org/echo" size="36"/>
<button id="connect">Connect</button>  
<br/>

<input id="text" type="text" />  
<button id="send">Send</button>  
<button id="disconnect">Disconnect</button>  
<br/>

<br/>
<div id="output"></div>  
</body>
</html>