Validate ip address and port

Xamarin.Neo4j/Xamarin.Neo4j/Xamarin.Neo4j/ViewModels/AddConnectionViewModel.cs

@@ -9,7 +9,9 @@
 
 using System;
 using System.ComponentModel;
+using System.Diagnostics;
 using System.Runtime.CompilerServices;
+using System.Text.RegularExpressions;
 using Acr.UserDialogs;
 using Xamarin.Essentials;
 using Xamarin.Forms;
@@ -41,7 +43,7 @@ namespace Xamarin.Neo4j.ViewModels
 
             Commands.Add("Test", new Command(async () =>
             {
-                // TODO: Validate input.
+                if (!ValidateInput()) return;
 
                 var connectionString = BuildConnectionString();
 
@@ -52,7 +54,7 @@ namespace Xamarin.Neo4j.ViewModels
 
             Commands.Add("Save", new Command(async () =>
             {
-                // TODO: Validate input.
+                if (!ValidateInput()) return;
 
                 var connectionString = BuildConnectionString();
 
@@ -70,7 +72,7 @@ namespace Xamarin.Neo4j.ViewModels
 
             Commands.Add("Connect", new Command(async () =>
             {
-                // TODO: Validate input.
+                if (!ValidateInput()) return;
 
                 var connectionString = BuildConnectionString();
 
@@ -103,6 +105,28 @@ namespace Xamarin.Neo4j.ViewModels
             };
         }
 
+        private bool ValidateInput()
+        {
+            // Username and Password not checked because username- and passwordless connections are allowed
+
+            var ipRegex = new Regex(@"\b((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(\.|$)){4}\b");
+            var portRegex = new Regex(@"^([0-9]{1,4}|[1-5][0-9]{4}|6[0-4][0-9]{3}|65[0-4][0-9]{2}|655[0-2][0-9]|6553[0-5])$");
+
+            if (!ipRegex.IsMatch(Host))
+            {
+                UserDialogs.Instance.AlertAsync("Incorrect host format");
+                return false;
+            }
+
+            if (!portRegex.IsMatch(Port.ToString()))
+            {
+                UserDialogs.Instance.AlertAsync("Incorrect port format");
+                return false;
+            }
+
+            return true;
+        }
+        
         #region Bindable Properties
 
         public bool Encrypted