feat: Add ability to send null old content to overwrite file

src/Uno.UI.RemoteControl.Server.Processors/HotReload/ServerHotReloadProcessor.cs

@@ -438,32 +438,29 @@ private async Task ProcessUpdateFile(UpdateFile message)
 
 			try
 			{
-				var (result, error) = DoUpdateFile();
+				var (result, error) = message switch
+				{
+					{ FilePath: null or { Length: 0 } } => (FileUpdateResult.BadRequest, "Invalid request (file path is empty)"),
+					{ OldText: not null, NewText: not null } => DoUpdate(message.OldText, message.NewText),
+					{ OldText: null, NewText: not null } => DoWrite(message.NewText),
+					{ NewText: null, IsCreateDeleteAllowed: true } => DoDelete(),
+					_ => (FileUpdateResult.BadRequest, "Invalid request")
+				};
 				if ((int)result < 300 && !message.IsForceHotReloadDisabled)
 				{
 					await RequestHotReloadToIde(hotReload.Id);
 				}
 
-				await _remoteControlServer.SendFrame(new UpdateFileResponse(message.RequestId, message.FilePath, result, error, hotReload.Id));
+				await _remoteControlServer.SendFrame(new UpdateFileResponse(message.RequestId, message.FilePath ?? "", result, error, hotReload.Id));
 			}
 			catch (Exception ex)
 			{
 				await hotReload.Complete(HotReloadServerResult.InternalError, ex);
-				await _remoteControlServer.SendFrame(new UpdateFileResponse(message.RequestId, message.FilePath, FileUpdateResult.Failed, ex.Message));
+				await _remoteControlServer.SendFrame(new UpdateFileResponse(message.RequestId, message.FilePath ?? "", FileUpdateResult.Failed, ex.Message));
 			}
 
-			(FileUpdateResult, string?) DoUpdateFile()
+			(FileUpdateResult, string?) DoUpdate(string oldText, string newText)
 			{
-				if (message?.IsValid() is not true)
-				{
-					if (this.Log().IsEnabled(LogLevel.Debug))
-					{
-						this.Log().LogDebug($"Got an invalid update file frame ({message}) [{message?.RequestId}].");
-					}
-
-					return (FileUpdateResult.BadRequest, "Invalid request");
-				}
-
 				if (!File.Exists(message.FilePath))
 				{
 					if (this.Log().IsEnabled(LogLevel.Debug))
@@ -474,21 +471,16 @@ private async Task ProcessUpdateFile(UpdateFile message)
 					return (FileUpdateResult.FileNotFound, $"Requested file '{message.FilePath}' does not exists.");
 				}
 
-				if (this.Log().IsEnabled(LogLevel.Debug))
-				{
-					this.Log().LogDebug($"Apply Changes to {message.FilePath} [{message.RequestId}].");
-				}
-
 				var originalContent = File.ReadAllText(message.FilePath);
 				if (this.Log().IsEnabled(LogLevel.Trace))
 				{
-					this.Log().LogTrace($"Original content: {message.FilePath} [{message.RequestId}].");
+					this.Log().LogTrace($"Original content: {originalContent} [{message.RequestId}].");
 				}
 
-				var updatedContent = originalContent.Replace(message.OldText, message.NewText);
+				var updatedContent = originalContent.Replace(oldText, newText);
 				if (this.Log().IsEnabled(LogLevel.Trace))
 				{
-					this.Log().LogTrace($"Updated content: {message.FilePath} [{message.RequestId}].");
+					this.Log().LogTrace($"Updated content: {updatedContent} [{message.RequestId}].");
 				}
 
 				if (updatedContent == originalContent)
@@ -504,6 +496,43 @@ private async Task ProcessUpdateFile(UpdateFile message)
 				File.WriteAllText(message.FilePath, updatedContent);
 				return (FileUpdateResult.Success, null);
 			}
+
+			(FileUpdateResult, string?) DoWrite(string newText)
+			{
+				if (!message.IsCreateDeleteAllowed && !File.Exists(message.FilePath))
+				{
+					if (this.Log().IsEnabled(LogLevel.Debug))
+					{
+						this.Log().LogDebug($"Requested file '{message.FilePath}' does not exists [{message.RequestId}].");
+					}
+
+					return (FileUpdateResult.FileNotFound, $"Requested file '{message.FilePath}' does not exists.");
+				}
+
+				if (this.Log().IsEnabled(LogLevel.Trace))
+				{
+					this.Log().LogTrace($"Write content: {newText} [{message.RequestId}].");
+				}
+
+				File.WriteAllText(message.FilePath, newText);
+				return (FileUpdateResult.Success, null);
+			}
+
+			(FileUpdateResult, string?) DoDelete()
+			{
+				if (!File.Exists(message.FilePath))
+				{
+					if (this.Log().IsEnabled(LogLevel.Debug))
+					{
+						this.Log().LogDebug($"Requested file '{message.FilePath}' does not exists [{message.RequestId}].");
+					}
+
+					return (FileUpdateResult.FileNotFound, $"Requested file '{message.FilePath}' does not exists.");
+				}
+
+				File.Delete(message.FilePath);
+				return (FileUpdateResult.Success, null);
+			}
 		}
 
 		private async Task<bool> RequestHotReloadToIde(long sequenceId)

src/Uno.UI.RemoteControl/HotReload/Messages/UpdateFile.cs

@@ -19,11 +19,23 @@ public class UpdateFile : IMessage
 	[JsonProperty]
 	public string FilePath { get; set; } = string.Empty;
 
+	/// <summary>
+	/// The old text to replace in the file, or `null` to create a new file (only if <see cref="IsCreateDeleteAllowed"/> is true).
+	/// </summary>
+	[JsonProperty]
+	public string? OldText { get; set; }
+
+	/// <summary>
+	/// The new text to replace in the file, or `null` to delete the file (only if <see cref="IsCreateDeleteAllowed"/> is true).
+	/// </summary>
 	[JsonProperty]
-	public string OldText { get; set; } = string.Empty;
+	public string? NewText { get; set; }
 
+	/// <summary>
+	/// Indicates if the file can be created or deleted.
+	/// </summary>
 	[JsonProperty]
-	public string NewText { get; set; } = string.Empty;
+	public bool IsCreateDeleteAllowed { get; set; }
 
 	/// <summary>
 	/// Disable the forced hot-reload requested on VS after the file has been modified.
@@ -37,6 +49,10 @@ public class UpdateFile : IMessage
 	[JsonIgnore]
 	string IMessage.Name => Name;
 
+	/// <summary>
+	/// LEGACY, indicates if valid for the legacy processor to handle it.
+	/// </summary>
+	/// <returns></returns>
 	[MemberNotNullWhen(true, nameof(FilePath), nameof(OldText), nameof(NewText))]
 	public bool IsValid()
 		=> !FilePath.IsNullOrEmpty() &&