fix port restart issue

.gitignore

@@ -1,6 +1,7 @@
 .sass-cache
 .DS_Store
 .start.pid
+.port.tmp
 public
 govuk_modules
 node_modules/*

lib/utils.js

@@ -1,6 +1,8 @@
 var basicAuth = require('basic-auth'),
-    prompt = require('prompt'),
-    portScanner = require('portscanner');
+    config = require(__dirname + '/../app/config.js'),
+    fs = require('fs');
+    portScanner = require('portscanner'),
+    prompt = require('prompt');
 
 /**
  * Simple basic auth middleware for use with Express 4.x.
@@ -35,17 +37,26 @@ exports.basicAuth = function(username, password) {
 
 exports.findAvailablePort = function(app){
 
-  var port = (process.env.PORT || 3000);
+  var port = null;
+
+  try {
+    port = Number(fs.readFileSync(__dirname+'/../.port.tmp'));
+  } catch (e){
+    port = (process.env.PORT || config.port);
+  }
 
   console.log('');
+
   // Check that default port is free, else offer to change
   portScanner.findAPortNotInUse(port, port+50, '127.0.0.1', function(error, availablePort) {
 
     if (port == availablePort){
+
       app.listen(port);
       console.log('Listening on port ' + port + '   url: http://localhost:' + port);
-    }
-    else {
+
+    } else {
+
       // Default port in use - offer to change to available port
       console.error("ERROR: Port " + port + " in use - you may have another prototype running.\n");
       // Set up prompt settings
@@ -63,17 +74,21 @@ exports.findAvailablePort = function(app){
         pattern: /y(es)?|no?/i,
         message: 'Please enter y or n'
       }], function (err, result) {
+
         if (result.answer.match(/y(es)?/i) ) {
           // User answers yes
           port = availablePort;
+          fs.writeFileSync(__dirname+'/../.port.tmp', port);
           app.listen(port);
           console.log('Changed to port ' + port + '   url: http://localhost:' + port);
-        }
-        else {
+
+        } else {
+
           // User answers no - exit
           console.log('\nYou can set a new default port in server.js, or by running the server with PORT=XXXX');
           console.log("\nExit by pressing 'ctrl + c'");
           process.exit(0);
+
         }
       });
     }

start.js

@@ -1,16 +1,29 @@
 // Check for `node_modules` folder and warn if missing
 var fs = require('fs');
+
 if (!fs.existsSync(__dirname + '/node_modules')) {
   console.error('ERROR: Node module folder missing. Try running `npm install`');
   process.exit(0);
 }
 
+// remove .port.tmp if it exists  
+try {
+  fs.unlinkSync(__dirname + '/.port.tmp');
+} catch(e){}
+
 var gruntfile = __dirname + '/Gruntfile.js';
+
 require(__dirname + '/node_modules/grunt/lib/grunt.js').cli({
   'gruntfile' : gruntfile
 });
 
 process.on('SIGINT', function() {
-  process.kill(process.pid, 'SIGTERM');
-  process.exit();
+
+  // remove .port.tmp if it exists  
+  try {
+    fs.unlinkSync(__dirname + '/.port.tmp');
+  } catch(e){}
+
+  process.exit(0);
+
 });