Claim a specific port without try other ports

Author: mgesmundo

lib/harbor.js

@@ -85,7 +85,7 @@ Object.defineProperty(Harbor.prototype, 'claimed',
 });
 
 /**
- * ### .claim (name, cb)
+ * ### _claim (name, cb)
  *
  * Find an available port from the pool of open
  * ports and claim it for a given name.
@@ -94,11 +94,11 @@ Object.defineProperty(Harbor.prototype, 'claimed',
  * @param {Function} callback
  * @cb {Error|null}
  * @cb {Number} claimed port
- * @name claim
- * @api public
+ * @name _claim
+ * @api private
  */
 
-Harbor.prototype.claim = function (name, cb) {
+function _claim(name, cb) {
   var self = this;
 
   if (this.ports[name]) {
@@ -113,6 +113,43 @@ Harbor.prototype.claim = function (name, cb) {
   });
 };
 
+/**
+ * ### .claim (name, cb)
+ *
+ * Find an available port from the pool of open
+ * ports (or use a provided port) and claim it for a given name.
+ *
+ * @param {String} name
+ * @param {Number} [port]
+ * @param {Function} callback
+ * @cb {Error|null}
+ * @cb {Number} claimed port
+ * @name claim
+ * @api public
+ */
+
+Harbor.prototype.claim = function (name, port, cb) {
+  var self = this;
+
+  if ('function' === typeof port) {
+    return _claim.call(this, name, port);
+  }
+
+  var _port = parseInt(port, 10);
+  if (!isNaN(_port) && _port > 0) {
+    if (this.ports[name]) {
+      return cb(null, this.ports[name]);
+    }
+
+    checkPort.call(this, _port, _port, function (err, port) {
+      if (err) return cb(err);
+      self.ports[name] = port;
+      self.emit('claim', name, port);
+      cb(null, port);
+    });
+  }
+};
+
 /**
  * ### .release (name)
  *
@@ -140,13 +177,19 @@ Harbor.prototype.release = function (name) {
  * Will attempt to connect to a given port. If success,
  * will disconnect and pass that number to a callback.
  *
- * @param {Object} range min/max
+ * @param {Number} num Port to check
+ * @param {Number} max Max port to check
  * @param {Function} callback
  */
 
-function checkPort (num, cb) {
+function checkPort (num, max, cb) {
   var self = this;
 
+  if ('function' === typeof max) {
+    cb = max;
+    max = this.max;
+  }
+
   // if already claimed, skip
   if (~this.claimed.indexOf(num)) {
     return process.nextTick(function () {
@@ -158,7 +201,7 @@ function checkPort (num, cb) {
 
   // if error, we don't want this server
   server.on('error', function (err) {
-    if (num == self.max) {
+    if (num == max) {
       self.emit('full');
       return cb(new Error('No ports available in range.'));
     }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "harbor",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "description": "TCP port availability and assignment utility.",
   "main": "index.js",
   "scripts": {

test/harbor.js

@@ -59,6 +59,27 @@ describe('harbor', function () {
       finder.ports.should.not.have.property('http');
     });
 
+    it('can claim a specific port', function (done) {
+      var claim = chai.spy(function (name, port) {
+        name.should.equal('http');
+        port.should.equal(4300);
+      });
+
+      var full = chai.spy();
+
+      finder.on('claim', claim);
+      finder.on('full', full);
+
+      finder.claim('http', 4300, function (err, port) {
+        Should.not.exist(err);
+        port.should.equal(4300);
+        finder.ports.should.have.property('http', 4300);
+        finder.claimed.should.include(4300);
+        claim.should.have.been.called.once;
+        full.should.have.not.been.called();
+        done();
+      });
+    });
   });
 
   describe('when port not available', function () {