modbus-serial - npm Package Compare versions

Comparing version 4.0.0 to 4.0.1

package.json

 {
   "name": "modbus-serial",
-  "version": "4.0.0",
+  "version": "4.0.1",
   "description": "A pure JavaScript implemetation of MODBUS-RTU (and TCP) for NodeJS.",
@@ -5,0 +5,0 @@ "main": "index.js",

ports/rtubufferedport.js

@@ -6,30 +6,9 @@ 'use strict';
 
-var crc16 = require('./../utils/crc16');
+var EXCEPTION_LENGTH = 5;
 
 /**
- * check if a buffer chunk can be a modbus answer
- * or modbus exception
- *
- * @param {RTUBufferedPort} modbus
- * @param {Buffer} buf the buffer to check.
- * @return {boolean} if the buffer can be an answer
- */
-function checkData(modbus, buf) {
-    // check buffer size
-    if (buf.length != modbus._length && buf.length != 5) return false;
-
-    // calculate crc16
-    var crcIn = buf.readUInt16LE(buf.length - 2);
-
-    // check buffer unit-id, command and crc
-    return (buf[0] == modbus._id &&
-        (0x7f & buf[1]) == modbus._cmd &&
-        crcIn == crc16(buf.slice(0, -2)));
-}
-
-/**
  * Simulate a modbus-RTU port using buffered serial connection
  */
 var RTUBufferedPort = function(path, options) {
-    var modbus = this;
+    var self = this;
 
@@ -49,35 +28,30 @@ // options
     // register the port data event
-    this._client.on('data', function(data) {
-        /* add data to buffer
-         */
-        modbus._buffer = Buffer.concat([modbus._buffer, data]);
+    this._client.on('data', function onData(data) {
+        // add data to buffer
+        self._buffer = Buffer.concat([self._buffer, data]);
 
-        /* check if buffer include a complete modbus answer
-         */
-        var length = modbus._length;
-        var bufferLength = modbus._buffer.length ;
+        // check if buffer include a complete modbus answer
+        var expectedLength = self._length;
+        var bufferLength = self._buffer.length ;
 
         // check data length
-        if (bufferLength < 5 || length < 6) return;
+        if (expectedLength < 6 || bufferLength < EXCEPTION_LENGTH) return;
 
         // loop and check length-sized buffer chunks
-        for (var i = 0; i < (bufferLength - length + 1); i++) {
-            // cut a length of bytes from buffer
-            var _data = modbus._buffer.slice(i, i + length);
+        var maxOffset = bufferLength - EXCEPTION_LENGTH;
+        for (var i = 0; i <= maxOffset; i++) {
+            var unitId = self._buffer[i];
+            var functionCode = self._buffer[i+1];
 
-            // check if this is the data we are waiting for
-            if (checkData(modbus, _data)) {
-                // adjust i to end of data chunk
-                i = i + length;
+            if (unitId !== self._id) continue;
 
-                // emit a data signal
-                modbus.emit('data', _data);
+            if (functionCode === self._cmd && i + expectedLength <= bufferLength) {
+                self._emitData(i, expectedLength);
+                return;
             }
+            if (functionCode === (0x80 | self._cmd) && i + EXCEPTION_LENGTH <= bufferLength) {
+                self._emitData(i, EXCEPTION_LENGTH);
+                return;
+            }
         }
-
-        /* cut checked data from buffer
-         */
-        if (i) {
-            modbus._buffer = modbus._buffer.slice(i);
-        }
     });
@@ -90,2 +64,18 @@
 /**
+ * Emit the received response, cut the buffer and reset the internal vars.
+ * @param {number} start the start index of the response within the buffer
+ * @param {number} length the length of the response
+ * @private
+ */
+RTUBufferedPort.prototype._emitData = function(start, length) {
+    this.emit('data', this._buffer.slice(start, start + length));
+    this._buffer = this._buffer.slice(start + length);
+
+    // reset internal vars
+    this._id = 0;
+    this._cmd = 0;
+    this._length = 0;
+};
+
+/**
  * Simulate successful port open
@@ -92,0 +82,0 @@ */

ports/telnetport.js

@@ -6,32 +6,10 @@ 'use strict';
 
-var crc16 = require('./../utils/crc16');
-
+var EXCEPTION_LENGTH = 5;
 var TELNET_PORT = 2217;
 
 /**
- * check if a buffer chunk can be a modbus answer
- * or modbus exception
- *
- * @param {TelnetPort} modbus
- * @param {Buffer} buf the buffer to check.
- * @return {boolean} if the buffer can be an answer
- */
-function checkData(modbus, buf) {
-    // check buffer size
-    if (buf.length != modbus._length && buf.length != 5) return false;
-
-    // calculate crc16
-    var crcIn = buf.readUInt16LE(buf.length - 2);
-
-    // check buffer unit-id, command and crc
-    return (buf[0] == modbus._id &&
-        (0x7f & buf[1]) == modbus._cmd &&
-        crcIn == crc16(buf.slice(0, -2)));
-}
-
-/**
  * Simulate a modbus-RTU port using Telent connection
  */
 var TelnetPort = function(ip, options) {
-    var modbus = this;
+    var self = this;
     this.ip = ip;
@@ -54,43 +32,38 @@ this.openFlag = false;
     // register the port data event
-    this._client.on('data', function(data) {
-        /* add data to buffer
-         */
-        modbus._buffer = Buffer.concat([modbus._buffer, data]);
+    this._client.on('data', function onData(data) {
+        // add data to buffer
+        self._buffer = Buffer.concat([self._buffer, data]);
 
-        /* check if buffer include a complete modbus answer
-         */
-        var length = modbus._length;
-        var bufferLength = modbus._buffer.length ;
+        // check if buffer include a complete modbus answer
+        var expectedLength = self._length;
+        var bufferLength = self._buffer.length ;
 
         // check data length
-        if (bufferLength < 5 || length < 6) return;
+        if (expectedLength < 6 || bufferLength < EXCEPTION_LENGTH) return;
 
         // loop and check length-sized buffer chunks
-        for (var i = 0; i < (bufferLength - length + 1); i++) {
-            // cut a length of bytes from buffer
-            var _data = modbus._buffer.slice(i, i + length);
+        var maxOffset = bufferLength - EXCEPTION_LENGTH;
+        for (var i = 0; i <= maxOffset; i++) {
+            var unitId = self._buffer[i];
+            var functionCode = self._buffer[i+1];
 
-            // check if this is the data we are waiting for
-            if (checkData(modbus, _data)) {
-                // adjust i to end of data chunk
-                i = i + length;
+            if (unitId !== self._id) continue;
 
-                // emit a data signal
-                modbus.emit('data', _data);
+            if (functionCode === self._cmd && i + expectedLength <= bufferLength) {
+                self._emitData(i, expectedLength);
+                return;
             }
+            if (functionCode === (0x80 | self._cmd) && i + EXCEPTION_LENGTH <= bufferLength) {
+                self._emitData(i, EXCEPTION_LENGTH);
+                return;
+            }
         }
-
-        /* cut checked data from buffer
-         */
-        if (i) {
-            modbus._buffer = modbus._buffer.slice(i);
-        }
     });
 
     this._client.on('connect', function() {
-        modbus.openFlag = true;
+        self.openFlag = true;
     });
 
     this._client.on('close', function(had_error) {
-        modbus.openFlag = false;
+        self.openFlag = false;
     });
@@ -103,2 +76,18 @@
 /**
+ * Emit the received response, cut the buffer and reset the internal vars.
+ * @param {number} start the start index of the response within the buffer
+ * @param {number} length the length of the response
+ * @private
+ */
+TelnetPort.prototype._emitData = function(start, length) {
+    this.emit('data', this._buffer.slice(start, start + length));
+    this._buffer = this._buffer.slice(start + length);
+
+    // reset internal vars
+    this._id = 0;
+    this._cmd = 0;
+    this._length = 0;
+};
+
+/**
  * Simulate successful port open
@@ -105,0 +94,0 @@ */

test/ports/rtubufferedport.test.js

@@ -70,2 +70,19 @@ 'use strict';
         });
+
+        it('should return a valid Modbus RTU exception', function(done) {
+            port.once('data', function(data) {
+                expect(data.toString('hex')).to.equal('1183044136');
+                done();
+            });
+            port.open(function() {
+                port.write(new Buffer('1103006B00037687', 'hex'));
+                setTimeout(function() {
+                    port._client.receive(new Buffer('11', 'hex'));
+                    port._client.receive(new Buffer('83', 'hex'));
+                    port._client.receive(new Buffer('04', 'hex'));
+                    port._client.receive(new Buffer('41', 'hex'));
+                    port._client.receive(new Buffer('36', 'hex'));
+                });
+            });
+        });
     });
@@ -72,0 +89,0 @@

test/ports/telnetport.test.js

@@ -70,2 +70,19 @@ 'use strict';
         });
+
+        it('should return a valid Modbus RTU exception', function(done) {
+            port.once('data', function(data) {
+                expect(data.toString('hex')).to.equal('1183044136');
+                done();
+            });
+            port.open(function() {
+                port.write(new Buffer('1103006B00037687', 'hex'));
+                setTimeout(function() {
+                    port._client.receive(new Buffer('11', 'hex'));
+                    port._client.receive(new Buffer('83', 'hex'));
+                    port._client.receive(new Buffer('04', 'hex'));
+                    port._client.receive(new Buffer('41', 'hex'));
+                    port._client.receive(new Buffer('36', 'hex'));
+                });
+            });
+        });
     });
@@ -72,0 +89,0 @@

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Found 1 instance in 1 package

Fixed alerts

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This package is not allowed per your license policy. Review the package's license to ensure compliance.

Found 1 instance in 1 package

Improved metrics

Lines of code

2635

increased by0.61%

Worsened metrics

Total package byte prevSize

107805

decreased by-4.54%

Number of package files

36

decreased by-5.26%

No dependency changes