ArtNet-Server: use jspack to unpack the UDP Datagram

.gitignore

@@ -0,0 +1,77 @@
+###OSX###
+
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# Icon must end with two \r
+Icon
+
+
+# Thumbnails
+._*
+
+# Files that might appear on external disk
+.Spotlight-V100
+.Trashes
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+
+###Windows###
+
+# Windows image file caches
+Thumbs.db
+ehthumbs.db
+
+# Folder config file
+Desktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Windows Installer files
+*.cab
+*.msi
+*.msm
+*.msp
+
+# Windows shortcuts
+*.lnk
+
+
+###Node###
+
+# Logs
+logs
+*.log
+
+# Runtime data
+pids
+*.pid
+*.seed
+
+# Directory for instrumented libs generated by jscoverage/JSCover
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+# Coverage directory used by tools like istanbul
+coverage
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+# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# Compiled binary addons (http://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directory
+# Commenting this out is preferred by some people, see
+# https://www.npmjs.org/doc/misc/npm-faq.html#should-i-check-my-node_modules-folder-into-git-
+node_modules
+
+# Users Environment Variables
+.lock-wscript

lib/artnet_server.js

@@ -1,28 +1,62 @@
 var util = require('util');
 var events = require('events');
 var dgram = require('dgram');
+var jspack = require('jspack').jspack;
+
+// jspack table for message format: (https://github.com/pgriess/node-jspack)
+//
+// Format | C Type         | JavaScript Type   | Size (octets) | Notes
+//     -------------------------------------------------------------------
+//        A   | char[]         | Array             |     Length     |  (1)
+//        x   | pad byte       | N/A               |        1       |
+//        c   | char           | string (length 1) |        1       |  (2)
+//        b   | signed char    | number            |        1       |  (3)
+//        B   | unsigned char  | number            |        1       |  (3)
+//        h   | signed short   | number            |        2       |  (3)
+//        H   | unsigned short | number            |        2       |  (3)
+//        i   | signed long    | number            |        4       |  (3)
+//        I   | unsigned long  | number            |        4       |  (3)
+//        l   | signed long    | number            |        4       |  (3)
+//        L   | unsigned long  | number            |        4       |  (3)
+//        s   | char[]         | string            |     Length     |  (2)
+//        f   | float          | number            |        4       |  (4)
+//        d   | double         | number            |        8       |  (5)
+
+// Packet Format of ArtNet Packet According to https://en.wikipedia.org/wiki/Art-Net
+var msgFormatHeader = '!7sBHHBBHH'
+// // Payload is between 2 and 512, so this is the maximal payload (can be trimmed later if necessary)
+var msgFormatMaxPayload = 'BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB'
 
 // ArtNet server class
 exports.listen = function(port, cb) {
 	this.port = port;
 	events.EventEmitter.call(this);
-
 	// Set up the socket
 	var sock = dgram.createSocket("udp4", function (msg, peer) {
-
-		var sequence = msg.readUInt8(12,true);	
-		var physical = msg.readUInt8(13,true);
-		var universe = msg.readUInt8(14,true);
-		var offset = msg.readUInt8(16,true);
-		var length = msg.readUInt8(17,true);
-
-		var rawData = [];
-
-		for( i = 18; i < 18 + length; i++ ){
-			rawData.push( msg.readUInt8(i) );
-		}
-
-		var retData = {sequence: sequence, physical: physical, universe: universe, length: length, data: rawData};
+		// Unpack the message
+
+		// Protocol Data
+		var unpacked = jspack.Unpack(msgFormatHeader, msg, 0);
+		var signature = unpacked[0];		// Signature should be 'Art-Net'
+		var zero = unpacked[1];				// It's just a zero per the format definition ;-)
+		var opcode = unpacked[2];			// Opcode is defined to be 0x5000
+		var protocolVersion = unpacked[3];	// Protocol Version should be 14
+
+		// TODO: Check for valid Header?
+
+		// ArtNet Data
+		var sequence = unpacked[4];
+		var physical = unpacked[5];
+		var universe = unpacked[6];
+		var length = unpacked[7];
+
+		// Unpack the payload 
+		// Payload is of variable length between 2 and 512, so the package format maybe has to be shorthened
+		var payloadFormat = msgFormatMaxPayload.substring(0, length);
+
+		var channelData = jspack.Unpack(payloadFormat, msg, 18);
+		// Build the associative array to return
+		var retData = {sequence: sequence, physical: physical, universe: universe, length: length, data: channelData};
 
 		// And call the callback passing the deseralized data
 		cb(retData, peer);

package.json

@@ -11,6 +11,10 @@
     {
         "name": "xandy",
         "email": "xandy@hackerspace-bamberg.de"
+    },
+    {
+      "name": "Markus Chmelar",
+      "email": "markus.chmelar@innovaptor.com"      
     }
   ],
   "main": "./main.js",
@@ -24,6 +28,7 @@
     "client"
   ],
   "dependencies" : {
+    "jspack": "0.0.4"
   }, 
   "engines": {
     "node": ">=0.6"