cleaned up port iteration, added methods to check ports from array, checking for proper port range

example/portscan.js

@@ -19,7 +19,7 @@ server.listen(3005, '127.0.0.1', function() {
   })
 
   // Finds a port that a service is listening on
-  portscanner.findAPortInUse(3000, 3010, '127.0.0.1', function(error, port) {
+  portscanner.findAPortInUse(3010, 3000, '127.0.0.1', function(error, port) {
     // Port should be 3005 as the HTTP server is listening on that port
     console.log('Found an open port at ' + port)
     if (error) console.error(error);
@@ -31,5 +31,20 @@ server.listen(3005, '127.0.0.1', function() {
     console.log('Found a closed port at ' + port)
     if (error) console.error(error);
   })
+
+  var list = [3000,3001,3002,3003,3004,3005,3006,3007,3008,3009,3010];
+  // Finds a port that a service is listening on
+  portscanner.findAPortInUseFromList(list, '127.0.0.1', function(error, port) {
+    // Port should be 3005 as the HTTP server is listening on that port
+    console.log('Found an open port of '+list+' at ' + port)
+    if (error) console.error(error);
+  })
+  // Finds a port no service is listening on
+  portscanner.findAPortNotInUseFromList(list, '127.0.0.1', function(error, port) {
+    // Will return any number between 3000 and 3010 (inclusive), that's not 3005.
+    // The order is unknown as the port status checks are asynchronous.
+    console.log('Found a closed port of '+list+' at ' + port)
+    if (error) console.error(error);
+  })
 })
 

lib/portscanner.js

@@ -20,7 +20,24 @@ var portscanner = exports
  *                              open port is found, the value is false.
  */
 portscanner.findAPortInUse = function(startPort, endPort, host, callback) {
-  findAPortWithStatus('open', startPort, endPort, host, callback)
+  findAPortWithStatus('open', makePortRangeIter(startPort, endPort), host, callback)
+}
+
+/**
+ * Finds the first port with a status of 'open', implying the port is in use and
+ * there is likely a service listening on it, taking possible ports from the list.
+ *
+ * @param {Array<Number>} list - List of ports to check.
+ * @param {String} host        - Where to scan. Defaults to '127.0.0.1'.
+ * @param {Function} callback  - function (error, port) { ... }
+ *   - {Object|null} error     - Any errors that occurred while port scanning.
+ *   - {Number|Boolean} port   - The first open port found. Note, this is the
+ *                               first port that returns status as 'open', not
+ *                               necessarily the first open port checked. If no
+ *                               open port is found, the value is false.
+ */
+portscanner.findAPortInUseFromList = function(list, host, callback) {
+  findAPortWithStatus('open', new ArrayIter(list), host, callback)
 }
 
 /**
@@ -39,7 +56,24 @@ portscanner.findAPortInUse = function(startPort, endPort, host, callback) {
  *                              closed port is found, the value is false.
  */
 portscanner.findAPortNotInUse = function(startPort, endPort, host, callback) {
-  findAPortWithStatus('closed', startPort, endPort, host, callback)
+  findAPortWithStatus('closed', makePortRangeIter(startPort, endPort), host, callback)
+}
+
+/**
+ * Finds the first port with a status of 'closed', implying the port is not in
+ * use, taking possible ports from the list.
+ *
+ * @param {Array<Number>} list - List of ports to check.
+ * @param {String} host        - Where to scan. Defaults to '127.0.0.1'.
+ * @param {Function} callback  - function (error, port) { ... }
+ *   - {Object|null} error     - Any errors that occurred while port scanning.
+ *   - {Number|Boolean} port   - The first closed port found. Note, this is the
+ *                               first port that returns status as 'closed', not
+ *                               necessarily the first closed port checked. If no
+ *                               closed port is found, the value is false.
+ */
+portscanner.findAPortNotInUseFromList = function(list, host, callback) {
+  findAPortWithStatus('closed', new ArrayIter(list), host, callback)
 }
 
 /**
@@ -107,45 +141,79 @@ portscanner.checkPortStatus = function(port, options, callback) {
   socket.connect(port, host)
 }
 
-function findAPortWithStatus(status, startPort, endPort, host, callback) {
-  endPort = endPort || 65535
+
+
+function findAPortWithStatus(status, ports, host, callback) {
   var foundPort = false
-  var numberOfPortsChecked = 0
-  var port = startPort
 
   // Returns true if a port with matching status has been found or if checked
   // the entire range of ports
-  var hasFoundPort = function() {
-    return foundPort || numberOfPortsChecked === (endPort - startPort + 1)
+  var hasFoundPortOrCheckedAll = function() {
+    return foundPort !== false || !ports.hasNext()
   }
 
   // Checks the status of the port
   var checkNextPort = function(callback) {
+    var port = ports.next();
+    // console.log('checking port', port);
     portscanner.checkPortStatus(port, host, function(error, statusOfPort) {
-      numberOfPortsChecked++
+      if(error != null) return callback(error);
+
       if (statusOfPort === status) {
-        foundPort = true
-        callback(error)
-      }
-      else {
-        port++
-        callback(null)
+        foundPort = port
       }
+
+      callback(null)
     })
   }
 
   // Check the status of each port until one with a matching status has been
   // found or the range of ports has been exhausted
-  async.until(hasFoundPort, checkNextPort, function(error) {
+  async.until(hasFoundPortOrCheckedAll, checkNextPort, function(error) {
     if (error) {
-      callback(error, port)
-    }
-    else if (foundPort) {
-      callback(null, port)
+      callback(error, null)
     }
     else {
-      callback(null, false)
+      callback(null, foundPort)
     }
   })
 }
 
+
+function RangeIterIncl(from, to){
+  this.cur = from;
+  this.end = to+1;
+}
+
+RangeIterIncl.prototype.hasNext = function(){
+  return this.cur < this.end
+}
+
+RangeIterIncl.prototype.next = function(){
+  return this.cur++
+}
+
+function ArrayIter(array){
+  this.array = array
+  this.len = array.length
+  this.idx = 0
+}
+
+ArrayIter.prototype.hasNext = function(){
+  return this.idx < this.len
+}
+
+ArrayIter.prototype.next = function(){
+  return this.array[this.idx++]
+}
+
+function makePortRangeIter(from, to){
+  from = from || 0
+  to = to || 65535
+  if(from < to){
+    return new RangeIterIncl(from, to)
+  }
+  else{
+    return new RangeIterIncl(to, from)
+  }
+}

package.json

@@ -8,7 +8,7 @@
     "checker",
     "status"
   ],
-  "version": "1.0.0",
+  "version": "1.0.1",
   "preferGlobal": false,
   "homepage": "https://github.com/baalexander/node-portscanner",
   "author": [