Checks a range of ports for first open or closed port.

Author: baalexander

example/portscan.js

@@ -4,8 +4,12 @@ portscanner.checkPortStatus('3000', 'localhost', function(error, status) {
   console.log(status)
 })
 
-portscanner.findAnAvailablePort(3000, 3010, 'localhost', function(error, port) {
-  console.log('AVAILABLE PORT AT ' + port)
+portscanner.findAnOpenPort(3000, 3010, 'localhost', function(error, port) {
+  console.log('OPEN PORT AT ' + port)
+})
+
+portscanner.findAClosedPort(3000, 3010, 'localhost', function(error, port) {
+  console.log('CLOSED PORT AT ' + port)
 })
 
 setTimeout(function() { }, 10000)

lib/portscanner.js

@@ -3,37 +3,14 @@ var net    = require('net')
 
 var portscanner = exports
 
-portscanner.findAnAvailablePort = function(startPort, endPort, host, callback) {
-  var that = this
-  var foundAvailablePort = false
-  var numberOfPortsChecked = 0
 
-  var check = function(port) {
-    that.checkPortStatus(port, host, function(error, status) {
-      numberOfPortsChecked++
-      // Only callback once
-      if (foundAvailablePort === false) {
-        if (error) {
-          foundAvailablePort = true
-          callback(error)
-        }
-        else {
-          if (status === 'open') {
-            foundAvailablePort = true
-            callback(null, port)
-          }
-          // All port checks have returned unavailable
-          else if (numberOfPortsChecked === (endPort - startPort + 1)) {
-            callback(null, false)
-          }
-        }
-      }
-    })
-  }
+portscanner.findAnOpenPort = function(startPort, endPort, host, callback) {
+  findAPortWithStatus('open', startPort, endPort, host, callback)
+}
+
+portscanner.findAClosedPort = function(startPort, endPort, host, callback) {
+  findAPortWithStatus('closed', startPort, endPort, host, callback)
 
-  for (var port = startPort; port <= endPort; port++) {
-    check(port)
-  }
 }
 
 portscanner.checkPortStatus = function(port, host, callback) {
@@ -67,3 +44,35 @@ portscanner.checkPortStatus = function(port, host, callback) {
   socket.connect(port, host)
 }
 
+function findAPortWithStatus(status, startPort, endPort, host, callback) {
+  var foundPort = false
+  var numberOfPortsChecked = 0
+
+  var check = function(port) {
+    portscanner.checkPortStatus(port, host, function(error, statusOfPort) {
+      numberOfPortsChecked++
+      // Only callback once
+      if (foundPort === false) {
+        if (error) {
+          foundPort = true
+          callback(error)
+        }
+        else {
+          if (statusOfPort === status) {
+            foundPort = true
+            callback(null, port)
+          }
+          // All port checks have returned unavailable
+          else if (numberOfPortsChecked === (endPort - startPort + 1)) {
+            callback(null, false)
+          }
+        }
+      }
+    })
+  }
+
+  for (var port = startPort; port <= endPort; port++) {
+    check(port)
+  }
+}
+