prevent crash if master calls a invalid / unknown function

client.js

@@ -50,7 +50,7 @@ Client.REQUESTS = {
   3: putTwoWord16be,
   // READ_INPUT_REGISTERS
   4: putTwoWord16be,
-  // WRITE_SINGLE_COIL
+  // WRITE_SINGLE_REGISTER:
   5: function(address, value) {
     if (typeof value !== 'boolean') throw new Error('"Write Single Coil" expects a \'boolean\' value');
     return putTwoWord16be(address, value ? 0xff00 : 0x0000);
@@ -69,17 +69,5 @@ Client.RESPONSES = {
       rtn.push(binary.end().vars.val);
     }
     return rtn;
-  },
-  // WRITE_SINGLE_COIL
-  5: function(bufferlist) {
-    var rtn = [];
-    var binary = Binary(bufferlist)
-      .getWord8('byteLength').end();
-    rtn.byteLength = binary.vars.byteLength;
-    for (var i=0, l=binary.vars.byteLength/2; i<l; i++) {
-      binary.getWord16be("val");
-      rtn.push(binary.end().vars.val);
-    }
-    return rtn;
-  },
+  }
 };

modbus-stack.js

@@ -190,7 +190,14 @@ ModbusResponseStack.prototype._onData = function(chunk) {
   } else if (this.requestHeader && this.functionCode >= 1 && this.bufferlist.length >= (this.requestHeader.length-2)) {
     // We have the complete request.
     if (!server.REQUESTS[this.functionCode]) {
-      return this.emit('error', new Error('"REQUESTS['+this.functionCode+']" in "server.js" is not implemented!'));
+		//this._gotRequest = true;
+		//this.writeException(1);
+      //return this.emit('error', new Error('"REQUESTS['+this.functionCode+']" in "server.js" is not implemented!'));
+
+      console.log(JSON.stringify(this.requestHeader));
+	  this.request = this.requestHeader;
+	  this._gotRequest = true;
+      return this.emit('not_implemented', this.request);
     }
     try {
       this.request = server.REQUESTS[this.functionCode].call(this, this.bufferlist);
@@ -206,6 +213,7 @@ ModbusResponseStack.prototype._onData = function(chunk) {
     //console.log('bufferlist.length: ' + this.bufferlist.length);
     this._gotRequest = true;
     this.emit('request', this.request);
+    //console.log("modbus-stack.js" +JSON.stringify(this.request));
   }
 }
 

package.json

@@ -2,7 +2,10 @@
   "name": "modbus-stack",
   "description": "A `StreamStack` implementation of the MODBUS protocol.",
   "version": "0.2.1",
-  "author": "Nathan Rajlich <nathan@tootallnate.net>",
+  "author": {
+    "name": "Nathan Rajlich",
+    "email": "nathan@tootallnate.net"
+  },
   "keywords": [
     "MODBUS",
     "protocol",
@@ -19,13 +22,20 @@
   },
   "main": "./modbus-stack",
   "scripts": {
-    "test": "expresso test/test*.js"
+    "test": "expresso test/test*.js",
+    "start": "node server.js"
   },
   "engines": {
     "node": ">= 0.3.0"
   },
   "directories": {},
-  "files": [
-    ""
-  ]
-}
+  "files": [],
+  "readme": "node-modbus-stack\n=================\n### A [StreamStack][] implementation of the [MODBUS][Modbus] protocol for [Node][].\n\nThis module exposes two concrete `StreamStack` implementations:\n`ModbusRequestStack` can be used as a MODBUS client (i.e. Master), and can write\nMODBUS compliant requests and listen for the response.\n`ModbusResponseStack` can be used to create a MODBUS server (i.e. Slave), by\nlistening for requests and providing a convenient API to respond with.\n\n[MODBUS][ModbusWiki] is an open building automation protocol that is widely used\nin various monitoring and controlling equipment. It's used with a variety of\ndifferent transports, including TCP.\n\nCurrently only communication through the TCP protocol is supported, however\nRS-485 serial support should be possible with [node-serialport]. I haven't\nhad a chance to look into it yet.\n\n\nA MODBUS Master (Client)\n------------------------\n\nYou will need to know which _Function Code_ (defined in the MODBUS specification)\nyou are invoking on the remote MODBUS slave. In this example, we'll request to\nread from the current values of the first 50 __Input Registers__ on the slave:\n\n    // 'RIR' contains the \"Function Code\" that we are going to invoke on the remote device\n    var RIR = require('modbus-stack').FUNCTION_CODES.READ_INPUT_REGISTERS;\n    \n    // IP and port of the MODBUS slave, default port is 502\n    var client = require('modbus-stack/client').createClient(502, '10.0.1.50');\n    \n    // 'req' is an instance of the low-level `ModbusRequestStack` class\n    var req = client.request(RIR, // Function Code: 4\n                             0,    // Start at address 0\n                             50);  // Read 50 contiguous registers from 0\n    \n    // 'response' is emitted after the entire contents of the response has been received.\n    req.on('response', function(registers) {\n      // An Array of length 50 filled with Numbers of the current registers.\n      console.log(registers);\n      client.end();\n    });\n\n\nA MODBUS Slave (Server)\n-----------------------\n\n`node-modbus-stack` makes it dead simple to create a compliant MODBUS Slave (or Server)\nwritten in pure JavaScript. Here's an example of a server that would respond to the\nrequest above:\n\n    var FC = require('modbus-stack').FUNCTION_CODES;\n    \n    // 'handlers' is an Object with keys containing the \"Function Codes\" that your MODBUS\n    // server will handle. Anything function code requested without a handler defined here\n    // will have the Server transparently respond with Exception Code 1 (\"Illegal Function\")\n    var handlers = {};\n    \n    // Define a handler for \"Read Input Registers\". We'll just respond with the register\n    // number requested. In a real-world situation, you'd probably look up these values from\n    // a database, etc.\n    handlers[FC.READ_INPUT_REGISTERS] = function(request, response) {\n      var start = request.startAddress;\n      var length = request.quantity;\n      \n      var resp = new Array(length);\n      for (var i=0; i<length; i++) {\n        resp[i] = start + i;\n      }\n      response.writeResponse(resp);\n    }\n\n    require('modbus-stack/server').createServer(handlers).listen(502);\n\nA \"catch-all\" function can be passed to `createServer()` instead of a \"handlers\" object, if you'd\nrather have a single callback invoked for _all_ MODBUS requests. Just be sure to call\n`writeException()` manually for any \"Function Codes\" your server isn't going to handle.\n\n\n[StreamStack]: http://github.com/TooTallNate/node-stream-stack\n[node-serialport]: https://github.com/voodootikigod/node-serialport\n[ModbusWiki]: http://en.wikipedia.org/wiki/Modbus\n[Modbus]: http://www.modbus.org\n[Node]: http://nodejs.org\n",
+  "readmeFilename": "README.md",
+  "_id": "modbus-stack@0.2.1",
+  "dist": {
+    "shasum": "83728431e6534f92d10c091d640f5a1419ab4c3c"
+  },
+  "_from": "modbus-stack@0.2.1",
+  "_resolved": "https://registry.npmjs.org/modbus-stack/-/modbus-stack-0.2.1.tgz"
+}

server.js

@@ -31,10 +31,21 @@ Server.prototype._setupConn = function(stream) {
       self._setupConn(stream);
     }
   });
+
+  response.on('not_implemented', function (request) {
+	  //console.log("on not_implemented");
+	  //console.log(JSON.stringify(request));
+	  self.emit('request', request, response);
+	  if (stream.readable && stream.writable) {
+		self._setupConn(stream);
+	  }
+  });
+
 }
 
 // Called for every 'request' event, when a "handlers" Object was passed.
 Server.prototype._handler = function(request, response) {
+ //console.log("server.js: " + JSON.stringify(request));
   if (request.functionCode in this.handlers) {
     this.handlers[request.functionCode].call(this, request, response);
   } else {
@@ -88,20 +99,39 @@ Server.REQUESTS = {
   // GET_COMM_EVENT_LOG (Serial Line Only)
   12: no_parameters,
   // REPORT_SLAVE_ID (Serial Line Only)
-  17: no_parameters
+  17: no_parameters,
+
+  //unknown function code - error case
+  //666: no_parameters
 };
 
 Server.RESPONSES = {
   // READ_INPUT_REGISTERS
   4: function(registers) {
-    if (!Array.isArray(registers) || registers.length != this.request.quantity) {
-      throw new Error('Expected to write an "Array" of length "'+this.request.quantity+'"');
-    }
-    var i=0, l=registers.length, put = Put()
-      .word8(registers.length*2);
-    for (; i<l; i++) {
-      put.word16be(registers[i]);
-    }
-    return put.buffer();
+		if(Buffer.isBuffer(registers) == false)
+			throw new Error('Expected to write an "Buffer"');
+		var put = Put();
+		put.word8(registers.length);
+		put.put(registers)
+		return(put.buffer());
+  },
+  // READ_HOLDING_REGISTERS
+  3: function(registers) {
+		if(Buffer.isBuffer(registers) == false)
+			throw new Error('Expected to write an "Buffer"');
+		var put = Put();
+		put.word8(registers.length);
+		put.put(registers)
+		return(put.buffer());
+  },
+  //WRITE_SINGLE_REGISTER
+  6: function(address,value) {
+		//if(Buffer.isBuffer(registers) == false)
+		//	throw new Error('Expected to write an "Buffer"');
+		var put = Put();
+		put.word16be(address);
+		put.word16be(value);
+		return(put.buffer());
   }
+
 };