small refactor of RandomPortFinder

test/Ocelot.AcceptanceTests/RandomPortFinder.cs

@@ -1,55 +1,58 @@
-using System;
+namespace Ocelot.AcceptanceTests
-using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Linq;
-using System.Net;
-using System.Net.Http;
-using System.Net.Sockets;
-using System.Text;
-
-namespace Ocelot.AcceptanceTests
 {
+    using System;
+    using System.Collections.Concurrent;
+    using System.Linq;
+    using System.Net;
+    using System.Net.Sockets;
+
     public static class RandomPortFinder
     {
-        private static readonly int TrialNumber = 100;
+        private const int TrialNumber = 100;
-        private static readonly int BeginPortRange = 20000;
+        private const int BeginPortRange = 20000;
-        private static readonly int EndPortRange = 45000;
+        private const int EndPortRange = 45000;
-
+        private static readonly Random Random = new Random();
-        private static Random random = new Random();
+        private static readonly ConcurrentBag<int> UsedPorts = new ConcurrentBag<int>();
-        private static ConcurrentBag<int> usedPorts = new ConcurrentBag<int>();
 
         public static int GetRandomPort()
         {
-            int randomPort = 0;
+            for (var i = 0; i < TrialNumber; i++)
-            for (int i = 0; i < TrialNumber; i++)
             {
-                randomPort = random.Next(BeginPortRange, EndPortRange);
+                var randomPort = Random.Next(BeginPortRange, EndPortRange);
-                if (usedPorts.Any(p => p == randomPort))
-                {
-                    continue;
-                }
-                else
-                {
-                    usedPorts.Add(randomPort);
-                }
 
-                try
+                if (!PortInUse(randomPort))
                 {
-                    IPEndPoint ipe = new IPEndPoint(IPAddress.Loopback, randomPort);
+                    try
-                    using (var socket = new Socket(ipe.AddressFamily, SocketType.Stream, ProtocolType.Tcp))
                     {
-                        socket.Bind(ipe);
+                        return UsePort(randomPort);
-                        socket.Close();
+                    }
-                        return randomPort;
+                    catch (Exception)
+                    {
+                        // ignored
                     }
                 }
-                catch (Exception)
-                {
-                    continue;
-                }                
             }
 
             throw new Exception("Cannot find available port to bind to.");
         }
+
+        private static int UsePort(int randomPort)
+        {
+            UsedPorts.Add(randomPort);
+
+            var ipe = new IPEndPoint(IPAddress.Loopback, randomPort);
+
+            using (var socket = new Socket(ipe.AddressFamily, SocketType.Stream, ProtocolType.Tcp))
+            {
+                socket.Bind(ipe);
+                socket.Close();
+                return randomPort;
+            }
+        }
+
+        private static bool PortInUse(int randomPort)
+        {
+            return UsedPorts.Any(p => p == randomPort);
+        }
     }
 }