Scan ports.

First commit related to scanning ports. This includes an actual scan of
the ports on a system with success and failure callbacks. Also, this
will fire a complete callback which happens at the end of the scan.

There are a number of options, undocumented at the moment.

There are a handful of tests but nearly extensive.

Signed-off-by: Nick Campbell <nicholas.j.campbell@gmail.com>

.gitignore

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+*.sw[a-z]
+node_modules

index.js

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+var net = require('net');
+
+
+function scan(port, opts, accum) {
+  if (!port) port = 1;
+  if (accum == undefined) accum = 0;
+  if (!opts) opts = {};
+  if (opts.startPort == undefined) opts.startPort = port;
+  if (!(opts.maxPort)) opts.maxPort = 65537; //exclusionary
+  if (!(opts.host)) opts.host = 'localhost';
+  if (opts.findActive == undefined) opts.findActive = true;
+  if (opts.findOne == undefined) opts.findOne = false;
+  if (!(opts.success)) opts.success = function(host, port) {
+  } 
+  if (!(opts.failure)) opts.failure = function(host, port) {
+  }
+  if (!(opts.complete)) opts.complete = function() {
+  }
+
+  function handleResponse(active, port, opts) {
+    var success = (opts.findActive === active);
+
+    if (success) {
+      accum++;
+      opts.success(opts.host, port);
+    } else {
+      opts.failure(opts.host, port);
+    }
+
+    if ((!success || (success && !(opts.findOne))) && port < opts.maxPort) {
+      return scan(++port, opts, accum);
+    } else {
+      return opts.complete({
+        count: (port - opts.startPort),
+        successes: accum,
+        failures: (((opts.maxPort > opts.startPort)?(opts.maxPort):opts.startPort+1)-opts.startPort-accum)
+      });
+    }
+  }
+
+  var _socket = new net.Socket();
+  var handled = false;
+  _socket.setTimeout(3000);
+  _socket.on('error', function() {
+    handled = true;
+    handleResponse(false, port, opts);
+  });
+  _socket.on('end', function() {
+    if (!handled) {
+      handleResponse(false, port, opts);
+    }
+  });
+  _socket.connect(port, opts.host, function() {
+    handled = true;
+    _socket.end();
+    handleResponse(true, port, opts);
+  });
+}
+
+module.exports = scan;

package.json

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+{
+  "name": "portscan",
+  "description": "port scanner in node, useful for finding an open port.",
+  "version": "0.0.1",
+  "keywords": ["port","scanner","scan","portscan","portscanner","port scan", "port scanner"],
+  "main": "./index",
+  "author": "Nick Campbell <nicholas.j.campbell@gmail.com>",
+  "repository": "https://github.com/ncb000gt/node-portscan.git",
+  "licenses": ["MIT"],
+  "bugs": "https://github.com/ncb000gt/node-portscan/issues",
+  "devDependencies": {
+    "mocha": "*"
+  }
+}

test/mocha.opts

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+--timeout 5000

test/suite/scan.js

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+var assert = require('assert'),
+    scan = require('../../index');
+
+describe('scan', function() {
+  it('calls back with active port', function(done) {
+    var successes = 0;
+    scan(0, {
+      findOne: true,
+      success: function() {
+        successes++;
+      },
+      complete: function(stats) {
+        assert.equal(stats.successes, 1);
+        assert.equal(stats.successes, successes);
+        done();
+      }
+    });
+  });
+
+  it('calls back with first inactive port', function(done) {
+    var successes = 0;
+    scan(0, {
+      findActive: false,
+      findOne: true,
+      success: function() {
+        successes++;
+      },
+      complete: function(stats) {
+        assert.equal(stats.successes, 1);
+        assert.equal(stats.successes, successes);
+        done();
+      }
+    });
+  });
+
+  it('calls back with high failures and no successes due to artificially large inactive port', function(done) {
+    var successes = 0;
+    var failures = 0;
+    scan(1000000, {
+      success: function() {
+        successes++;
+      },
+      failure: function() {
+        failures++;
+      },
+      complete: function(stats) {
+        assert.equal(stats.successes, 0);
+        assert.ok(stats.failures >= 1);
+        assert.equal(successes, 0);
+        assert.equal(stats.failures, failures);
+        done();
+      }
+    });
+  });
+});