Add backup settings to Hosts File Editor

microsoft · Mar 5, 2025 · 0a5f143 · 0a5f143
1 parent fc94cd7
commit 0a5f143
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Showing 15 changed files with 518 additions and 76 deletions.
diff --git a/src/modules/Hosts/Hosts.FuzzTests/FuzzTests.cs b/src/modules/Hosts/Hosts.FuzzTests/FuzzTests.cs
@@ -1,11 +1,7 @@
 // Copyright (c) Microsoft Corporation
 // The Microsoft Corporation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
-using System;
-using System.IO;
-using System.IO.Abstractions.TestingHelpers;
 using System.Text.RegularExpressions;
-using System.Threading.Tasks;
 
 using Hosts.Tests.Mocks;
 using HostsUILib.Helpers;
@@ -19,6 +15,7 @@ public class FuzzTests
     {
         private static Mock<IUserSettings> _userSettings;
         private static Mock<IElevationHelper> _elevationHelper;
+        private static Mock<IBackupManager> _backupManager;
 
         // Case1： Fuzzing method for ValidIPv4
         public static void FuzzValidIPv4(ReadOnlySpan<byte> input)
@@ -73,9 +70,10 @@ public static void FuzzWriteAsync(ReadOnlySpan<byte> data)
                 _userSettings = new Mock<IUserSettings>();
                 _elevationHelper = new Mock<IElevationHelper>();
                 _elevationHelper.Setup(m => m.IsElevated).Returns(true);
+                _backupManager = new Mock<IBackupManager>();
 
                 var fileSystem = new CustomMockFileSystem();
-                var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object);
+                var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object, _backupManager.Object);
 
                 string input = System.Text.Encoding.UTF8.GetString(data);
 

diff --git a/src/modules/Hosts/Hosts.FuzzTests/Hosts.FuzzTests.csproj b/src/modules/Hosts/Hosts.FuzzTests/Hosts.FuzzTests.csproj
@@ -28,6 +28,8 @@
 	  <Compile Include="..\HostsUILib\Settings\HostsAdditionalLinesPosition.cs" Link="HostsAdditionalLinesPosition.cs" />
 	  <Compile Include="..\HostsUILib\Settings\HostsEncoding.cs" Link="HostsEncoding.cs" />
 	  <Compile Include="..\HostsUILib\Settings\IUserSettings.cs" Link="IUserSettings.cs" />
+	  <Compile Include="..\HostsUILib\Helpers\IBackupManager.cs" Link="IBackupManager.cs" />
+	  <Compile Include="..\HostsUILib\Helpers\BackupManager.cs" Link="BackupManager.cs" />
 	</ItemGroup>
 
 	<ItemGroup>

diff --git a/src/modules/Hosts/Hosts.Tests/BackupManagerTest.cs b/src/modules/Hosts/Hosts.Tests/BackupManagerTest.cs
@@ -0,0 +1,105 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.IO.Abstractions.TestingHelpers;
+using HostsUILib.Helpers;
+using HostsUILib.Settings;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Moq;
+
+namespace Hosts.Tests
+{
+    [TestClass]
+    public class BackupManagerTest
+    {
+        private const string HostsPath = @"C:\Windows\System32\Drivers\etc\hosts";
+        private const string BackupPath = @"C:\Backup\hosts";
+        private const string BackupSearchPattern = $"*_PowerToysBackup_*";
+
+        [TestMethod]
+        public void Hosts_Backup_Not_Done()
+        {
+            var fileSystem = new MockFileSystem();
+            SetupFiles(fileSystem, false);
+            var userSettings = new Mock<IUserSettings>();
+            userSettings.Setup(m => m.BackupHosts).Returns(false);
+            userSettings.Setup(m => m.BackupPath).Returns(BackupPath);
+            var backupManager = new BackupManager(fileSystem, userSettings.Object);
+            backupManager.CreateBackup(HostsPath);
+
+            Assert.AreEqual(0, fileSystem.Directory.GetFiles(BackupPath, BackupSearchPattern).Length);
+        }
+
+        [TestMethod]
+        public void Hosts_Backup_Done_Once()
+        {
+            var fileSystem = new MockFileSystem();
+            SetupFiles(fileSystem, false);
+            var userSettings = new Mock<IUserSettings>();
+            userSettings.Setup(m => m.BackupHosts).Returns(true);
+            userSettings.Setup(m => m.BackupPath).Returns(BackupPath);
+            var backupManager = new BackupManager(fileSystem, userSettings.Object);
+            backupManager.CreateBackup(HostsPath);
+            backupManager.CreateBackup(HostsPath);
+
+            Assert.AreEqual(1, fileSystem.Directory.GetFiles(BackupPath, BackupSearchPattern).Length);
+            var hostsContent = fileSystem.File.ReadAllText(HostsPath);
+            var backupContent = fileSystem.File.ReadAllText(fileSystem.Directory.GetFiles(BackupPath, BackupSearchPattern)[0]);
+            Assert.AreEqual(hostsContent, backupContent);
+        }
+
+        [DataTestMethod]
+        [DataRow(false, 1, 1)]
+        [DataRow(true, 0, 0)]
+        [DataRow(true, -1, -1)]
+        public void Hosts_Backup_Not_Deleted(bool deleteBackup, int daysToKeep, int copiesToKeep)
+        {
+            var fileSystem = new MockFileSystem();
+            SetupFiles(fileSystem, true);
+            var userSettings = new Mock<IUserSettings>();
+            userSettings.Setup(m => m.BackupPath).Returns(BackupPath);
+            userSettings.Setup(m => m.DeleteBackups).Returns(deleteBackup);
+            userSettings.Setup(m => m.DaysToKeep).Returns(daysToKeep);
+            userSettings.Setup(m => m.CopiesToKeep).Returns(copiesToKeep);
+            var backupManager = new BackupManager(fileSystem, userSettings.Object);
+            backupManager.DeleteBackups();
+
+            Assert.AreEqual(10, fileSystem.Directory.GetFiles(BackupPath, BackupSearchPattern).Length);
+        }
+
+        // MockFileSystem doesn't support CreationTime, so we can't test the DaysToKeep logic
+        [DataTestMethod]
+        [DataRow(0, 4, 4)]
+        [DataRow(2, 4, 4)]
+        public void Hosts_Backup_Deleted(int daysToKeep, int copiesToKeep, int expectedBackups)
+        {
+            var fileSystem = new MockFileSystem();
+            SetupFiles(fileSystem, true);
+            var userSettings = new Mock<IUserSettings>();
+            userSettings.Setup(m => m.BackupPath).Returns(BackupPath);
+            userSettings.Setup(m => m.DeleteBackups).Returns(true);
+            userSettings.Setup(m => m.DaysToKeep).Returns(daysToKeep);
+            userSettings.Setup(m => m.CopiesToKeep).Returns(copiesToKeep);
+            var backupManager = new BackupManager(fileSystem, userSettings.Object);
+            backupManager.DeleteBackups();
+
+            Assert.AreEqual(expectedBackups + 1, fileSystem.Directory.GetFiles(BackupPath).Length);
+            Assert.AreEqual(expectedBackups, fileSystem.Directory.GetFiles(BackupPath, BackupSearchPattern).Length);
+        }
+
+        private void SetupFiles(MockFileSystem fileSystem, bool addBackups)
+        {
+            fileSystem.AddFile(HostsPath, new MockFileData("HOSTS FILE CONTENT"));
+            fileSystem.AddFile(fileSystem.Path.Combine(BackupPath, "unrelated_file"), new MockFileData(string.Empty));
+
+            if (addBackups)
+            {
+                for (var i = 0; i < 10; i++)
+                {
+                    fileSystem.AddEmptyFile(fileSystem.Path.Combine(BackupPath, $"hosts_PowerToysBackup_{i}"));
+                }
+            }
+        }
+    }
+}
diff --git a/src/modules/Hosts/Hosts.Tests/HostsServiceTest.cs b/src/modules/Hosts/Hosts.Tests/HostsServiceTest.cs
@@ -20,36 +20,18 @@ namespace Hosts.Tests
     [TestClass]
     public class HostsServiceTest
     {
+        private const string BackupPath = @"C:\Backup\hosts";
         private static Mock<IUserSettings> _userSettings;
         private static Mock<IElevationHelper> _elevationHelper;
+        private static Mock<IBackupManager> _backupManager;
 
         [ClassInitialize]
         public static void ClassInitialize(TestContext context)
         {
             _userSettings = new Mock<IUserSettings>();
             _elevationHelper = new Mock<IElevationHelper>();
             _elevationHelper.Setup(m => m.IsElevated).Returns(true);
-        }
-
-        [TestMethod]
-        public void Hosts_Exists()
-        {
-            var fileSystem = new CustomMockFileSystem();
-            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object);
-            fileSystem.AddFile(service.HostsFilePath, new MockFileData(string.Empty));
-            var result = service.Exists();
-
-            Assert.IsTrue(result);
-        }
-
-        [TestMethod]
-        public void Hosts_Not_Exists()
-        {
-            var fileSystem = new CustomMockFileSystem();
-            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object);
-            var result = service.Exists();
-
-            Assert.IsFalse(result);
+            _backupManager = new Mock<IBackupManager>();
         }
 
         [TestMethod]
@@ -67,7 +49,7 @@ 10.1.1.2  host2 host2.local   # another comment
 ";
 
             var fileSystem = new CustomMockFileSystem();
-            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object);
+            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object, _backupManager.Object);
             fileSystem.AddFile(service.HostsFilePath, new MockFileData(content));
 
             var data = await service.ReadAsync();
@@ -92,7 +74,7 @@ 10.1.1.2 host2 host2.local # another comment
 ";
 
             var fileSystem = new CustomMockFileSystem();
-            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object);
+            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object, _backupManager.Object);
             fileSystem.AddFile(service.HostsFilePath, new MockFileData(content));
 
             var data = await service.ReadAsync();
@@ -118,7 +100,7 @@ 10.1.1.2  host2 host2.local           # another comment
 ";
 
             var fileSystem = new CustomMockFileSystem();
-            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object);
+            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object, _backupManager.Object);
             fileSystem.AddFile(service.HostsFilePath, new MockFileData(content));
 
             var data = await service.ReadAsync();
@@ -137,7 +119,7 @@ 10.1.1.2  host2 host2.local           # another comment
         public async Task Empty_Hosts()
         {
             var fileSystem = new CustomMockFileSystem();
-            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object);
+            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object, _backupManager.Object);
             fileSystem.AddFile(service.HostsFilePath, new MockFileData(string.Empty));
 
             await service.WriteAsync(string.Empty, Enumerable.Empty<Entry>());
@@ -168,7 +150,7 @@ 10.1.1.2 host2 host2.local # another comment
             var fileSystem = new CustomMockFileSystem();
             var userSettings = new Mock<IUserSettings>();
             userSettings.Setup(m => m.AdditionalLinesPosition).Returns(HostsAdditionalLinesPosition.Top);
-            var service = new HostsService(fileSystem, userSettings.Object, _elevationHelper.Object);
+            var service = new HostsService(fileSystem, userSettings.Object, _elevationHelper.Object, _backupManager.Object);
             fileSystem.AddFile(service.HostsFilePath, new MockFileData(content));
 
             var data = await service.ReadAsync();
@@ -200,7 +182,7 @@ 10.1.1.2 host2 host2.local # another comment
             var fileSystem = new CustomMockFileSystem();
             var userSettings = new Mock<IUserSettings>();
             userSettings.Setup(m => m.AdditionalLinesPosition).Returns(HostsAdditionalLinesPosition.Bottom);
-            var service = new HostsService(fileSystem, userSettings.Object, _elevationHelper.Object);
+            var service = new HostsService(fileSystem, userSettings.Object, _elevationHelper.Object, _backupManager.Object);
             fileSystem.AddFile(service.HostsFilePath, new MockFileData(content));
 
             var data = await service.ReadAsync();
@@ -224,7 +206,7 @@ 10.1.1.1 host19                                                         # commen
 ";
 
             var fileSystem = new CustomMockFileSystem();
-            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object);
+            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object, _backupManager.Object);
             fileSystem.AddFile(service.HostsFilePath, new MockFileData(content));
 
             var data = await service.ReadAsync();
@@ -241,15 +223,15 @@ public async Task Save_NotRunningElevatedException()
             var elevationHelper = new Mock<IElevationHelper>();
             elevationHelper.Setup(m => m.IsElevated).Returns(false);
 
-            var service = new HostsService(fileSystem, _userSettings.Object, elevationHelper.Object);
+            var service = new HostsService(fileSystem, _userSettings.Object, elevationHelper.Object, _backupManager.Object);
             await Assert.ThrowsExceptionAsync<NotRunningElevatedException>(async () => await service.WriteAsync("# Empty hosts file", Enumerable.Empty<Entry>()));
         }
 
         [TestMethod]
         public async Task Save_ReadOnlyHostsException()
         {
             var fileSystem = new CustomMockFileSystem();
-            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object);
+            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object, _backupManager.Object);
 
             var hostsFile = new MockFileData(string.Empty)
             {
@@ -265,7 +247,7 @@ public async Task Save_ReadOnlyHostsException()
         public void Remove_ReadOnly_Attribute()
         {
             var fileSystem = new CustomMockFileSystem();
-            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object);
+            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object, _backupManager.Object);
 
             var hostsFile = new MockFileData(string.Empty)
             {
@@ -284,7 +266,7 @@ public void Remove_ReadOnly_Attribute()
         public async Task Save_Hidden_Hosts()
         {
             var fileSystem = new CustomMockFileSystem();
-            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object);
+            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object, _backupManager.Object);
 
             var hostsFile = new MockFileData(string.Empty)
             {
@@ -298,5 +280,56 @@ public async Task Save_Hidden_Hosts()
             var hidden = fileSystem.FileInfo.New(service.HostsFilePath).Attributes.HasFlag(FileAttributes.Hidden);
             Assert.IsTrue(hidden);
         }
+
+        [TestMethod]
+        public async Task Hosts_Backup_Not_Done()
+        {
+            var content =
+@"10.1.1.1 host host.local # comment
+10.1.1.2 host2 host2.local # another comment
+";
+
+            var fileSystem = new CustomMockFileSystem();
+            fileSystem.AddDirectory(BackupPath);
+            _userSettings.Setup(m => m.BackupHosts).Returns(false);
+            _userSettings.Setup(m => m.BackupPath).Returns(BackupPath);
+            var backupManager = new BackupManager(fileSystem, _userSettings.Object);
+            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object, backupManager);
+
+            fileSystem.AddFile(service.HostsFilePath, new MockFileData(content));
+
+            var data = await service.ReadAsync();
+            var entries = data.Entries.ToList();
+            entries.Add(new Entry(0, "10.1.1.30", "host30 host30.local", "new entry", false));
+            await service.WriteAsync(data.AdditionalLines, data.Entries);
+
+            Assert.AreEqual(0, fileSystem.Directory.GetFiles(BackupPath).Length);
+        }
+
+        [TestMethod]
+        public async Task Hosts_Backup_Done()
+        {
+            var content =
+@"10.1.1.1 host host.local # comment
+10.1.1.2 host2 host2.local # another comment
+";
+
+            var fileSystem = new CustomMockFileSystem();
+            _userSettings.Setup(m => m.BackupHosts).Returns(true);
+            _userSettings.Setup(m => m.BackupPath).Returns(BackupPath);
+            var backupManager = new BackupManager(fileSystem, _userSettings.Object);
+            var service = new HostsService(fileSystem, _userSettings.Object, _elevationHelper.Object, backupManager);
+
+            fileSystem.AddFile(service.HostsFilePath, new MockFileData(content));
+
+            var data = await service.ReadAsync();
+            var entries = data.Entries.ToList();
+            entries.Add(new Entry(0, "10.1.1.30", "host30 host30.local", "new entry", false));
+            await service.WriteAsync(data.AdditionalLines, data.Entries);
+
+            Assert.AreEqual(1, fileSystem.Directory.GetFiles(BackupPath).Length);
+            var backupContent = fileSystem.File.ReadAllText(fileSystem.Directory.GetFiles(BackupPath)[0]);
+            Assert.AreEqual(content, backupContent);
+        }
     }
 }
diff --git a/src/modules/Hosts/Hosts/HostsXAML/App.xaml.cs b/src/modules/Hosts/Hosts/HostsXAML/App.xaml.cs
@@ -53,6 +53,7 @@ public App()
                 {
                     // Core Services
                     services.AddSingleton<IFileSystem, FileSystem>();
+                    services.AddSingleton<IBackupManager, BackupManager>();
                     services.AddSingleton<IHostsService, HostsService>();
                     services.AddSingleton<IUserSettings, Hosts.Settings.UserSettings>();
                     services.AddSingleton<IElevationHelper, ElevationHelper>();
@@ -71,7 +72,7 @@ public App()
                 }).
                 Build();
 
-            var cleanupBackupThread = new Thread(() =>
+            var deleteBackupThread = new Thread(() =>
             {
                 // Delete old backups only if running elevated
                 if (!Host.GetService<IElevationHelper>().IsElevated)
@@ -81,16 +82,16 @@ public App()
 
                 try
                 {
-                    Host.GetService<IHostsService>().CleanupBackup();
+                    Host.GetService<IBackupManager>().DeleteBackups();
                 }
                 catch (Exception ex)
                 {
                     Logger.LogError("Failed to delete backup", ex);
                 }
             });
 
-            cleanupBackupThread.IsBackground = true;
-            cleanupBackupThread.Start();
+            deleteBackupThread.IsBackground = true;
+            deleteBackupThread.Start();
 
             UnhandledException += App_UnhandledException;