Add configurable max length to input

JamesNK · JamesNK · commit bc9968f874d7 · 2025-07-19T13:46:45.000+08:00
diff --git a/playground/Stress/Stress.AppHost/InteractionCommands.cs b/playground/Stress/Stress.AppHost/InteractionCommands.cs
@@ -127,8 +127,8 @@ public static IResourceBuilder<T> AddInteractionCommands<T>(this IResourceBuilde
                var numberOfPeopleInput = new InteractionInput { InputType = InputType.Number, Label = "Number of people", Placeholder = "Enter number of people", Value = "2", Required = true };
                var inputs = new List<InteractionInput>
                {
-                   new InteractionInput { InputType = InputType.Text, Label = "Name", Placeholder = "Enter name", Required = true },
-                   new InteractionInput { InputType = InputType.SecretText, Label = "Password", Placeholder = "Enter password", Required = true },
+                   new InteractionInput { InputType = InputType.Text, Label = "Name", Placeholder = "Enter name", Required = true, MaxLength = 50 },
+                   new InteractionInput { InputType = InputType.SecretText, Label = "Password", Placeholder = "Enter password", Required = true, MaxLength = 20 },
                    dinnerInput,
                    numberOfPeopleInput,
                    new InteractionInput { InputType = InputType.Boolean, Label = "Remember me", Placeholder = "What does this do?", Required = true },
diff --git a/src/Aspire.Dashboard/Aspire.Dashboard.csproj b/src/Aspire.Dashboard/Aspire.Dashboard.csproj
@@ -270,7 +270,8 @@
     <Compile Include="$(SharedDir)ConsoleLogs\LogEntry.cs" Link="Utils\ConsoleLogs\LogEntry.cs" />
     <Compile Include="$(SharedDir)ConsoleLogs\LogPauseViewModel.cs" Link="Utils\ConsoleLogs\LogPauseViewModel.cs" />
     <Compile Include="$(SharedDir)ConsoleLogs\TimestampParser.cs" Link="Utils\ConsoleLogs\TimestampParser.cs" />
-    <Compile Include="..\Shared\KnownUrls.cs" Link="Utils\KnownUrls.cs" />
+    <Compile Include="$(SharedDir)KnownUrls.cs" Link="Utils\KnownUrls.cs" />
+    <Compile Include="$(SharedDir)InteractionHelpers.cs" Link="Utils\InteractionHelpers.cs" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/Aspire.Dashboard/Components/Dialogs/InteractionsInputDialog.razor b/src/Aspire.Dashboard/Components/Dialogs/InteractionsInputDialog.razor
@@ -33,10 +33,6 @@
         <FluentStack Orientation="Orientation.Vertical" VerticalGap="12">
             @foreach (var vm in _inputDialogInputViewModels)
             {
-                @*
-                * AutoComplete value of one-time-code on password input prevents the browser asking to save the value.
-                * Immediate value of true on text inputs ensures the value is set to the server token with every key press in textbox.
-                *@
                 var localItem = vm;
                 var descriptionId = !string.IsNullOrEmpty(localItem.Input.Description)
                     ? $"{_elementRefs[localItem]?.Id}-description"
@@ -45,18 +41,25 @@
                     @switch (vm.Input.InputType)
                     {
                         case InputType.Text:
+                            @*
+                            * Immediate value of true on text input ensures the value is set to the server token with every key press in textbox.
+                            *@
                             <FluentTextField @ref="@_elementRefs[localItem]"
                                              @bind-Value="localItem.Value"
                                              Label="@localItem.Input.Label"
                                              Placeholder="@localItem.Input.Placeholder"
                                              Required="localItem.Input.Required"
                                              Immediate="true"
                                              aria-describedby="@descriptionId"
-                                             Maxlength="@MaxTextLength" />
+                                             Maxlength="@GetMaxLength(localItem)" />
                             @GetDescriptionContent(localItem.Input, descriptionId)
                             <ValidationMessage For="@(() => localItem.Value)" />
                             break;
                         case InputType.SecretText:
+                            @*
+                            * AutoComplete value of one-time-code on password input prevents the browser asking to save the value.
+                            * Immediate value of true on text input ensures the value is set to the server token with every key press in textbox.
+                            *@
                             <FluentTextField @ref="@_elementRefs[localItem]"
                                              @bind-Value="localItem.Value"
                                              Label="@localItem.Input.Label"
@@ -66,7 +69,7 @@
                                              AutoComplete="one-time-code"
                                              Immediate="true"
                                              aria-describedby="@descriptionId"
-                                             Maxlength="@MaxTextLength" />
+                                             Maxlength="@GetMaxLength(localItem)" />
                             @GetDescriptionContent(localItem.Input, descriptionId)
                             <ValidationMessage For="@(() => localItem.Value)" />
                             break;
diff --git a/src/Aspire.Dashboard/Components/Dialogs/InteractionsInputDialog.razor.cs b/src/Aspire.Dashboard/Components/Dialogs/InteractionsInputDialog.razor.cs
@@ -171,4 +171,14 @@ private async Task CancelAsync()
     {
         await Dialog.CancelAsync();
     }
+
+    private static int GetMaxLength(InputViewModel inputModel)
+    {
+        if (inputModel.Input.MaxLength == 0)
+        {
+            return MaxTextLength;
+        }
+
+        return inputModel.Input.MaxLength;
+    }
 }
diff --git a/src/Aspire.Hosting/Aspire.Hosting.csproj b/src/Aspire.Hosting/Aspire.Hosting.csproj
@@ -42,6 +42,7 @@
     <Compile Include="$(SharedDir)PortAllocator.cs" Link="Publishing\PortAllocator.cs" />
     <Compile Include="$(SharedDir)OverloadResolutionPriorityAttribute.cs" Link="Utils\OverloadResolutionPriorityAttribute.cs" />
     <Compile Include="$(SharedDir)PackageUpdateHelpers.cs" Link="Utils\PackageUpdateHelpers.cs" />
+    <Compile Include="$(SharedDir)InteractionHelpers.cs" Link="Utils\InteractionHelpers.cs" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/Aspire.Hosting/Dashboard/DashboardService.cs b/src/Aspire.Hosting/Dashboard/DashboardService.cs
@@ -143,6 +143,10 @@ async Task WatchInteractionsInternal(CancellationToken cancellationToken)
                                 {
                                     dto.Options.Add(input.Options.ToDictionary());
                                 }
+                                if (input.MaxLength != null)
+                                {
+                                    dto.MaxLength = input.MaxLength.Value;
+                                }
                                 dto.ValidationErrors.AddRange(input.ValidationErrors);
                                 return dto;
                             }).ToList();
diff --git a/src/Aspire.Hosting/Dashboard/proto/dashboard_service.proto b/src/Aspire.Hosting/Dashboard/proto/dashboard_service.proto
@@ -376,6 +376,7 @@ message InteractionInput {
     repeated string validation_errors = 7;
     string description = 8;
     bool enable_description_markdown = 9;
+    int32 max_length = 10;
 }
 enum MessageIntent {
     MESSAGE_INTENT_NONE = 0;
diff --git a/src/Aspire.Hosting/IInteractionService.cs b/src/Aspire.Hosting/IInteractionService.cs
@@ -103,8 +103,6 @@ public interface IInteractionService
 [Experimental(InteractionService.DiagnosticId, UrlFormat = "https://aka.ms/aspire/diagnostics/{0}")]
 public sealed class InteractionInput
 {
-    internal const int MaxTextLength = 8000;
-
     /// <summary>
     /// Gets or sets the label for the input.
     /// </summary>
@@ -146,6 +144,23 @@ public sealed class InteractionInput
     /// </summary>
     public string? Placeholder { get; set; }
 
+    /// <summary>
+    /// gets or sets the maximum length for text inputs.
+    /// </summary>
+    public int? MaxLength
+    {
+        get => field;
+        set
+        {
+            if (value is { } v)
+            {
+                ArgumentOutOfRangeException.ThrowIfLessThanOrEqual(v, 0);
+            }
+
+            field = value;
+        }
+    }
+
     internal List<string> ValidationErrors { get; } = [];
 }
 
diff --git a/src/Aspire.Hosting/InteractionService.cs b/src/Aspire.Hosting/InteractionService.cs
@@ -264,9 +264,11 @@ private async Task<bool> RunValidationAsync(Interaction interactionState, Intera
                         {
                             case InputType.Text:
                             case InputType.SecretText:
-                                if (value.Length > InteractionInput.MaxTextLength)
+                                var maxLength = InteractionHelpers.GetMaxLength(input.MaxLength);
+
+                                if (value.Length > maxLength)
                                 {
-                                    context.AddValidationError(input, $"Value length exceeds {InteractionInput.MaxTextLength} characters.");
+                                    context.AddValidationError(input, $"Value length exceeds {maxLength} characters.");
                                 }
                                 break;
                             case InputType.Choice:
diff --git a/src/Shared/InteractionHelpers.cs b/src/Shared/InteractionHelpers.cs
@@ -0,0 +1,27 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Buffers;
+using System.Diagnostics;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace Aspire;
+
+internal static class InteractionHelpers
+{
+    // Chosen to balance between being long enough for most normal use but provides a default limit
+    // to prevent possible abuse of interactions API.
+    public const int DefaultMaxLength = 8000;
+
+    public static int GetMaxLength(int? configuredInputLength)
+    {
+        // An unconfigured max length uses the default.
+        if (configuredInputLength is null || configuredInputLength == 0)
+        {
+            return DefaultMaxLength;
+        }
+
+        return configuredInputLength.Value;
+    }
+}
diff --git a/tests/Aspire.Hosting.Tests/InteractionServiceTests.cs b/tests/Aspire.Hosting.Tests/InteractionServiceTests.cs
@@ -282,6 +282,45 @@ public async Task PromptInputsAsync_BooleanHasNonBooleanValue_ReturnErrors()
             error => Assert.Equal("Value must be a valid boolean.", error));
     }
 
+    [Theory]
+    [InlineData(InputType.Text, null)]
+    [InlineData(InputType.Text, 1)]
+    [InlineData(InputType.Text, 10)]
+    [InlineData(InputType.Text, InteractionHelpers.DefaultMaxLength)]
+    [InlineData(InputType.SecretText, 10)]
+    public async Task PromptInputsAsync_TextExceedsLimit_ReturnErrors(InputType inputType, int? maxLength)
+    {
+        await TextExceedsLimitCoreAsync(inputType, maxLength, success: true);
+        await TextExceedsLimitCoreAsync(inputType, maxLength, success: false);
+
+        static async Task TextExceedsLimitCoreAsync(InputType inputType, int? maxLength, bool success)
+        {
+            var interactionService = CreateInteractionService();
+
+            var input = new InteractionInput { Label = "Value", InputType = inputType, MaxLength = maxLength };
+            var resultTask = interactionService.PromptInputAsync("Please provide", "please", input);
+
+            var interaction = Assert.Single(interactionService.GetCurrentInteractions());
+            var resolvedMaxLength = InteractionHelpers.GetMaxLength(maxLength);
+
+            input.Value = new string('!', success ? resolvedMaxLength : resolvedMaxLength + 1);
+            await CompleteInteractionAsync(interactionService, interaction.InteractionId, new InteractionCompletionState { Complete = true, State = new[] { input } });
+
+            if (!success)
+            {
+                // The interaction should still be in progress due to invalid data
+                Assert.False(interaction.CompletionTcs.Task.IsCompleted);
+
+                Assert.Collection(input.ValidationErrors,
+                    error => Assert.Equal($"Value length exceeds {resolvedMaxLength} characters.", error));
+            }
+            else
+            {
+                Assert.True(interaction.CompletionTcs.Task.IsCompletedSuccessfully);
+            }
+        }
+    }
+
     [Fact]
     public void InteractionInput_WithDescription_SetsProperties()
     {
@@ -335,6 +374,36 @@ public void InteractionInput_WithNullDescription_AllowsNullValue()
         Assert.False(input.EnableDescriptionMarkdown);
     }
 
+    [Theory]
+    [InlineData(null, false)]
+    [InlineData(1, false)]
+    [InlineData(int.MaxValue, false)]
+    [InlineData(0, true)]
+    [InlineData(-1, true)]
+    [InlineData(int.MinValue, true)]
+    public void InteractionInput_WithLengths_ErrorOnInvalid(int? length, bool invalid)
+    {
+        // Arrange & Act
+        if (invalid)
+        {
+            Assert.Throws<ArgumentOutOfRangeException>(() => SetLength(length));
+        }
+        else
+        {
+            SetLength(length);
+        }
+
+        static void SetLength(int? length)
+        {
+            var input = new InteractionInput
+            {
+                Label = "Test Label",
+                InputType = InputType.Text,
+                MaxLength = length
+            };
+        }
+    }
+
     private static async Task CompleteInteractionAsync(InteractionService interactionService, int interactionId, InteractionCompletionState state)
     {
         await interactionService.CompleteInteractionAsync(interactionId, (_, _) => state, CancellationToken.None);

Original file line number	Diff line number	Diff line change
`@@ -171,4 +171,14 @@ private async Task CancelAsync()`
`171`	`171`	`{`
`172`	`172`	`await Dialog.CancelAsync();`
`173`	`173`	`}`
	`174`	`+`
	`175`	`+ private static int GetMaxLength(InputViewModel inputModel)`
	`176`	`+ {`
	`177`	`+ if (inputModel.Input.MaxLength == 0)`
	`178`	`+ {`
	`179`	`+ return MaxTextLength;`
	`180`	`+ }`
	`181`	`+`
	`182`	`+ return inputModel.Input.MaxLength;`
	`183`	`+ }`
`174`	`184`	`}`
Original file line number	Diff line number	Diff line change
`@@ -143,6 +143,10 @@ async Task WatchInteractionsInternal(CancellationToken cancellationToken)`
`143`	`143`	`{`
`144`	`144`	`dto.Options.Add(input.Options.ToDictionary());`
`145`	`145`	`}`
	`146`	`+ if (input.MaxLength != null)`
	`147`	`+ {`
	`148`	`+ dto.MaxLength = input.MaxLength.Value;`
	`149`	`+ }`
`146`	`150`	`dto.ValidationErrors.AddRange(input.ValidationErrors);`
`147`	`151`	`return dto;`
`148`	`152`	`}).ToList();`
Original file line number	Diff line number	Diff line change
`@@ -376,6 +376,7 @@ message InteractionInput {`
`376`	`376`	`repeated string validation_errors = 7;`
`377`	`377`	`string description = 8;`
`378`	`378`	`bool enable_description_markdown = 9;`
	`379`	`+ int32 max_length = 10;`
`379`	`380`	`}`
`380`	`381`	`enum MessageIntent {`
`381`	`382`	`MESSAGE_INTENT_NONE = 0;`
Original file line number	Diff line number	Diff line change
`@@ -264,9 +264,11 @@ private async Task<bool> RunValidationAsync(Interaction interactionState, Intera`
`264`	`264`	`{`
`265`	`265`	`case InputType.Text:`
`266`	`266`	`case InputType.SecretText:`
`267`		`- if (value.Length > InteractionInput.MaxTextLength)`
	`267`	`+ var maxLength = InteractionHelpers.GetMaxLength(input.MaxLength);`
	`268`	`+`
	`269`	`+ if (value.Length > maxLength)`
`268`	`270`	`{`
`269`		`- context.AddValidationError(input, $"Value length exceeds {InteractionInput.MaxTextLength} characters.");`
	`271`	`+ context.AddValidationError(input, $"Value length exceeds {maxLength} characters.");`
`270`	`272`	`}`
`271`	`273`	`break;`
`272`	`274`	`case InputType.Choice:`