Add payload serializer guardrails

README.md

@@ -101,8 +101,9 @@ dotnet dotnet-ef migrations add <MigrationName> --project RpgRoller/RpgRoller.cs
 - Browser interop is in `RpgRoller/wwwroot/js/rpgroller-api.js`.
 - Workspace reads are resolved server-side through scoped query services; browser interop remains for browser-only concerns such as session storage, SSE wiring, and DOM helpers.
 - Live workspace refreshes now compare separate roster, per-character sheet, and log versions so unrelated state changes do not force a full roster + sheet + log reload.
-- Workspace campaign data is loaded in bounded slices: visible campaign summaries, a selected campaign roster, a selected character sheet, and a 50-row incremental log window backed by `/api/campaigns/{campaignId}/log/page`.
+- Workspace campaign data is loaded in bounded slices: visible campaign summaries, a selected campaign roster, a selected character sheet, and a 25-row incremental log window backed by `/api/campaigns/{campaignId}/log/page`.
 - Campaign log rows now ship compact summary data first and lazy-load dice + breakdown detail through `/api/rolls/{rollId}` only when a row is expanded.
+- Hot API contracts share a source-generated `System.Text.Json` context, and HTTP JSON responses are gzip-compressed when the client advertises support.
 - OpenAPI contract source remains at `openapi/RpgRoller.json`.
 
 ## Test and Coverage
@@ -111,6 +112,7 @@ dotnet dotnet-ef migrations add <MigrationName> --project RpgRoller/RpgRoller.cs
   ```powershell
   dotnet test RpgRoller.Tests/RpgRoller.Tests.csproj --collect:"XPlat Code Coverage" --settings RpgRoller.Tests/coverlet.runsettings
   ```
+- Regression tests enforce payload budgets for the hottest contracts: character sheet reads, initial log page loads, incremental log updates, and roll mutation responses.
 - Coverage gate:
   ```powershell
   pwsh ./scripts/check-coverage.ps1 -MinLineRate 0.90 -MinBranchRate 0.70

RpgRoller.Tests/Api/ResponseCompressionApiTests.cs

@@ -0,0 +1,27 @@
+namespace RpgRoller.Tests;
+
+public sealed class ResponseCompressionApiTests : ApiTestBase
+{
+    public ResponseCompressionApiTests(WebApplicationFactory<Program> factory) : base(factory)
+    {
+    }
+
+    [Fact]
+    public async Task AuthenticatedJsonResponses_EnableGzipCompression()
+    {
+        using var factory = CreateFactory();
+        using var client = factory.CreateClient(new() { AllowAutoRedirect = false });
+
+        await RegisterAsync(client, "gm-compress", "Password123", "GM");
+        await LoginAsync(client, "gm-compress", "Password123");
+        _ = await PostAsync<CreateCampaignRequest, CampaignSummary>(client, "/api/campaigns", new("Compressed", "d6"));
+
+        var request = new HttpRequestMessage(HttpMethod.Get, "/api/campaigns");
+        request.Headers.Add("Accept-Encoding", "gzip");
+
+        var response = await client.SendAsync(request);
+
+        response.EnsureSuccessStatusCode();
+        Assert.Contains("gzip", response.Content.Headers.ContentEncoding);
+    }
+}

RpgRoller.Tests/PayloadBudgetTests.cs

@@ -0,0 +1,127 @@
+using System.Text.Json;
+using RpgRoller.Contracts;
+
+namespace RpgRoller.Tests;
+
+public sealed class PayloadBudgetTests
+{
+    [Fact]
+    public void CharacterSheetPayload_StaysWithinBudget()
+    {
+        using var harness = ServiceTestSupport.CreateHarness();
+        var service = harness.Service;
+
+        service.Register("gm-sheet", "Password123", "GM");
+        service.Register("owner-sheet", "Password123", "Owner");
+
+        var gmSession = ServiceTestSupport.GetValue(service.Login("gm-sheet", "Password123")).SessionToken;
+        var ownerSession = ServiceTestSupport.GetValue(service.Login("owner-sheet", "Password123")).SessionToken;
+
+        var campaign = ServiceTestSupport.GetValue(service.CreateCampaign(gmSession, "Payload Sheet", "d6"));
+        var character = ServiceTestSupport.GetValue(service.CreateCharacter(ownerSession, "Payload Hero", campaign.Id));
+
+        var groupIds = new List<Guid>
+        {
+            ServiceTestSupport.GetValue(service.CreateSkillGroup(ownerSession, character.Id, "Combat", "2D+1", 1, true)).Id,
+            ServiceTestSupport.GetValue(service.CreateSkillGroup(ownerSession, character.Id, "Social", "2D+1", 1, true)).Id,
+            ServiceTestSupport.GetValue(service.CreateSkillGroup(ownerSession, character.Id, "Knowledge", "2D+1", 1, true)).Id,
+            ServiceTestSupport.GetValue(service.CreateSkillGroup(ownerSession, character.Id, "Survival", "2D+1", 1, true)).Id
+        };
+
+        for (var i = 0; i < 18; i++)
+        {
+            Guid? skillGroupId = i < 16 ? groupIds[i % groupIds.Count] : null;
+            _ = ServiceTestSupport.GetValue(service.CreateSkill(ownerSession, character.Id, $"Skill {i:D2}", "2D+1", 1, true, skillGroupId));
+        }
+
+        var sheet = ServiceTestSupport.GetValue(service.GetCharacterSheet(ownerSession, character.Id));
+        AssertPayloadWithinBudget(sheet, 12 * 1024, "initial character sheet");
+    }
+
+    [Fact]
+    public void CampaignLogInitialPagePayload_StaysWithinBudget()
+    {
+        using var harness = ServiceTestSupport.CreateHarness(CreateScriptedRolls(220));
+        var service = harness.Service;
+
+        service.Register("gm-log-budget", "Password123", "GM");
+        service.Register("owner-log-budget", "Password123", "Owner");
+
+        var gmSession = ServiceTestSupport.GetValue(service.Login("gm-log-budget", "Password123")).SessionToken;
+        var ownerSession = ServiceTestSupport.GetValue(service.Login("owner-log-budget", "Password123")).SessionToken;
+
+        var campaign = ServiceTestSupport.GetValue(service.CreateCampaign(gmSession, "Payload Log", "d6"));
+        var character = ServiceTestSupport.GetValue(service.CreateCharacter(ownerSession, "Log Hero", campaign.Id));
+        var skill = ServiceTestSupport.GetValue(service.CreateSkill(ownerSession, character.Id, "Stealth", "2D+1", 1, true));
+
+        for (var i = 0; i < 25; i++)
+            _ = ServiceTestSupport.GetValue(service.RollSkill(ownerSession, skill.Id, "public"));
+
+        var page = ServiceTestSupport.GetValue(service.GetCampaignLogPage(gmSession, campaign.Id, limit: 25));
+        AssertPayloadWithinBudget(page, 8 * 1024, "initial log page");
+    }
+
+    [Fact]
+    public void CampaignLogIncrementalPayload_StaysWithinBudget()
+    {
+        using var harness = ServiceTestSupport.CreateHarness(CreateScriptedRolls(240));
+        var service = harness.Service;
+
+        service.Register("gm-log-delta", "Password123", "GM");
+        service.Register("owner-log-delta", "Password123", "Owner");
+
+        var gmSession = ServiceTestSupport.GetValue(service.Login("gm-log-delta", "Password123")).SessionToken;
+        var ownerSession = ServiceTestSupport.GetValue(service.Login("owner-log-delta", "Password123")).SessionToken;
+
+        var campaign = ServiceTestSupport.GetValue(service.CreateCampaign(gmSession, "Payload Delta", "d6"));
+        var character = ServiceTestSupport.GetValue(service.CreateCharacter(ownerSession, "Delta Hero", campaign.Id));
+        var skill = ServiceTestSupport.GetValue(service.CreateSkill(ownerSession, character.Id, "Stealth", "2D+1", 1, true));
+
+        for (var i = 0; i < 25; i++)
+            _ = ServiceTestSupport.GetValue(service.RollSkill(ownerSession, skill.Id, "public"));
+
+        var initialPage = ServiceTestSupport.GetValue(service.GetCampaignLogPage(gmSession, campaign.Id, limit: 25));
+        _ = ServiceTestSupport.GetValue(service.RollSkill(ownerSession, skill.Id, "public"));
+
+        var incrementalPage = ServiceTestSupport.GetValue(service.GetCampaignLogPage(gmSession, campaign.Id, initialPage.Cursor, 25));
+        AssertPayloadWithinBudget(incrementalPage, 2 * 1024, "incremental log update");
+    }
+
+    [Fact]
+    public void RollResultPayload_StaysWithinJsInteropBudget()
+    {
+        using var harness = ServiceTestSupport.CreateHarness(CreateScriptedRolls(40));
+        var service = harness.Service;
+
+        service.Register("gm-roll-budget", "Password123", "GM");
+        service.Register("owner-roll-budget", "Password123", "Owner");
+
+        var gmSession = ServiceTestSupport.GetValue(service.Login("gm-roll-budget", "Password123")).SessionToken;
+        var ownerSession = ServiceTestSupport.GetValue(service.Login("owner-roll-budget", "Password123")).SessionToken;
+
+        var campaign = ServiceTestSupport.GetValue(service.CreateCampaign(gmSession, "Payload Roll", "d6"));
+        var character = ServiceTestSupport.GetValue(service.CreateCharacter(ownerSession, "Roll Hero", campaign.Id));
+        var skill = ServiceTestSupport.GetValue(service.CreateSkill(ownerSession, character.Id, "Wild Roll", "6D+3", 3, true));
+
+        var roll = ServiceTestSupport.GetValue(service.RollSkill(ownerSession, skill.Id, "public"));
+        AssertPayloadWithinBudget(roll, 16 * 1024, "roll mutation response");
+    }
+
+    private static void AssertPayloadWithinBudget<T>(T payload, int maxBytes, string label)
+    {
+        var byteCount = JsonSerializer.SerializeToUtf8Bytes(payload, SerializerOptions).Length;
+        Assert.True(byteCount <= maxBytes, $"{label} payload was {byteCount} bytes, above the {maxBytes}-byte budget.");
+    }
+
+    private static int[] CreateScriptedRolls(int count)
+    {
+        var values = new[] { 6, 5, 4, 3, 2, 1 };
+        var scriptedRolls = new int[count];
+        for (var i = 0; i < count; i++)
+            scriptedRolls[i] = values[i % values.Length];
+
+        return scriptedRolls;
+    }
+
+    private static readonly JsonSerializerOptions SerializerOptions = RpgRollerJson.CreateSerializerOptions();
+}

RpgRoller/Components/Pages/Workspace.razor.cs

@@ -1236,7 +1236,7 @@ public partial class Workspace : IAsyncDisposable
     private const string CampaignSessionKey = "campaign";
     private const string MobilePanelSessionKey = "play-panel";
     private const string RollVisibilitySessionKey = "roll-visibility";
-    private const int CampaignLogWindowSize = 50;
+    private const int CampaignLogWindowSize = 25;
     private const int ToastDurationMs = 3200;
 
     private sealed record WorkspaceToast(Guid Id, string Message, bool IsError);

RpgRoller/Components/RpgRollerApiClient.cs

@@ -1,5 +1,6 @@
 using System.Text.Json;
 using Microsoft.JSInterop;
+using RpgRoller.Contracts;
 
 namespace RpgRoller.Components;
 
@@ -37,7 +38,7 @@ public sealed class RpgRollerApiClient
             throw new ApiRequestException(response.Status, response.Error ?? "Request failed.");
     }
 
-    private static readonly JsonSerializerOptions JsonOptions = new(JsonSerializerDefaults.Web);
+    private static readonly JsonSerializerOptions JsonOptions = RpgRollerJson.CreateSerializerOptions();
     private readonly IJSRuntime m_Js;
 }
 

RpgRoller/Contracts/RpgRollerJson.cs

@@ -0,0 +1,19 @@
+using System.Text.Json;
+
+namespace RpgRoller.Contracts;
+
+public static class RpgRollerJson
+{
+    public static JsonSerializerOptions CreateSerializerOptions()
+    {
+        var options = new JsonSerializerOptions(JsonSerializerDefaults.Web);
+        Configure(options);
+        return options;
+    }
+
+    public static void Configure(JsonSerializerOptions options)
+    {
+        if (!options.TypeInfoResolverChain.Contains(RpgRollerJsonSerializerContext.Default))
+            options.TypeInfoResolverChain.Insert(0, RpgRollerJsonSerializerContext.Default);
+    }
+}

RpgRoller/Contracts/RpgRollerJsonSerializerContext.cs

@@ -0,0 +1,58 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace RpgRoller.Contracts;
+
+[JsonSourceGenerationOptions(JsonSerializerDefaults.Web)]
+[JsonSerializable(typeof(ApiError))]
+[JsonSerializable(typeof(AdminUserSummary))]
+[JsonSerializable(typeof(AdminUserSummary[]))]
+[JsonSerializable(typeof(CampaignGmSummary))]
+[JsonSerializable(typeof(CampaignLogEntry))]
+[JsonSerializable(typeof(CampaignLogEntry[]))]
+[JsonSerializable(typeof(CampaignLogListEntry))]
+[JsonSerializable(typeof(CampaignLogListEntry[]))]
+[JsonSerializable(typeof(CampaignLogPage))]
+[JsonSerializable(typeof(CampaignOption))]
+[JsonSerializable(typeof(CampaignOption[]))]
+[JsonSerializable(typeof(CampaignRollDetail))]
+[JsonSerializable(typeof(CampaignRoster))]
+[JsonSerializable(typeof(CampaignStateSnapshot))]
+[JsonSerializable(typeof(CampaignSummary))]
+[JsonSerializable(typeof(CampaignSummary[]))]
+[JsonSerializable(typeof(CharacterSheet))]
+[JsonSerializable(typeof(CharacterSheetSkill))]
+[JsonSerializable(typeof(CharacterSheetSkillGroup))]
+[JsonSerializable(typeof(CharacterStateVersion))]
+[JsonSerializable(typeof(CharacterStateVersion[]))]
+[JsonSerializable(typeof(CharacterSummary))]
+[JsonSerializable(typeof(CharacterSummary[]))]
+[JsonSerializable(typeof(CreateCampaignRequest))]
+[JsonSerializable(typeof(CreateCharacterRequest))]
+[JsonSerializable(typeof(CreateSkillGroupRequest))]
+[JsonSerializable(typeof(CreateSkillRequest))]
+[JsonSerializable(typeof(HealthResponse))]
+[JsonSerializable(typeof(IReadOnlyList<AdminUserSummary>))]
+[JsonSerializable(typeof(IReadOnlyList<CharacterStateVersion>))]
+[JsonSerializable(typeof(IReadOnlyList<RollDieResult>))]
+[JsonSerializable(typeof(IReadOnlyList<string>))]
+[JsonSerializable(typeof(LoginRequest))]
+[JsonSerializable(typeof(MeResponse))]
+[JsonSerializable(typeof(RegisterRequest))]
+[JsonSerializable(typeof(RollDieResult))]
+[JsonSerializable(typeof(RollDieResult[]))]
+[JsonSerializable(typeof(RollResult))]
+[JsonSerializable(typeof(RollSkillRequest))]
+[JsonSerializable(typeof(RulesetDefinition))]
+[JsonSerializable(typeof(RulesetDefinition[]))]
+[JsonSerializable(typeof(SkillGroupSummary))]
+[JsonSerializable(typeof(SkillSummary))]
+[JsonSerializable(typeof(string[]))]
+[JsonSerializable(typeof(UpdateCharacterRequest))]
+[JsonSerializable(typeof(UpdateSkillGroupRequest))]
+[JsonSerializable(typeof(UpdateSkillRequest))]
+[JsonSerializable(typeof(UpdateUserRolesRequest))]
+[JsonSerializable(typeof(UserSummary))]
+public partial class RpgRollerJsonSerializerContext : JsonSerializerContext
+{
+}

RpgRoller/Program.cs

@@ -1,10 +1,18 @@
+using Microsoft.AspNetCore.ResponseCompression;
 using RpgRoller.Api;
 using RpgRoller.Components;
+using RpgRoller.Contracts;
 using RpgRoller.Hosting;
 
 var builder = WebApplication.CreateBuilder(args);
 builder.Services.AddRpgRollerCore(builder.Configuration, builder.Environment);
 builder.Services.AddRazorComponents().AddInteractiveServerComponents();
+builder.Services.AddResponseCompression(options =>
+{
+    options.EnableForHttps = true;
+    options.MimeTypes = ResponseCompressionDefaults.MimeTypes.Concat(["application/json"]);
+});
+builder.Services.ConfigureHttpJsonOptions(options => RpgRollerJson.Configure(options.SerializerOptions));
 builder.Services.AddHttpContextAccessor();
 builder.Services.AddScoped<RpgRollerApiClient>();
 builder.Services.AddScoped<WorkspaceSessionTokenAccessor>();
@@ -25,6 +33,7 @@ if (!string.IsNullOrWhiteSpace(configuredPathBase))
         app.UsePathBase(normalizedPathBase);
 }
 
+app.UseResponseCompression();
 app.UseStaticFiles();
 app.UseAntiforgery();
 

RpgRoller/Services/GameService.cs

@@ -797,7 +797,7 @@ public sealed class GameService : IGameService
 
             var (user, campaign) = context.Value!;
             var entries = GetVisibleCampaignLogEntriesLocked(user, campaign)
-                .TakeLast(CampaignLogPageSize)
+                .TakeLast(CampaignLogHistoryWindowSize)
                 .Select(ToLogEntry)
                 .ToArray();
 
@@ -1596,9 +1596,9 @@ public sealed class GameService : IGameService
     private static int NormalizeCampaignLogPageSize(int? limit)
     {
         if (!limit.HasValue)
-            return CampaignLogPageSize;
+            return CampaignLogLivePageSize;
 
-        return Math.Clamp(limit.Value, 1, CampaignLogPageSize);
+        return Math.Clamp(limit.Value, 1, CampaignLogLivePageSize);
     }
 
     private static UserAccount CloneUser(UserAccount user)
@@ -1692,8 +1692,9 @@ public sealed class GameService : IGameService
         };
     }
 
-    private const int CampaignLogPageSize = 100;
-    private static readonly JsonSerializerOptions DiceJsonOptions = new(JsonSerializerDefaults.Web);
+    private const int CampaignLogHistoryWindowSize = 100;
+    private const int CampaignLogLivePageSize = 25;
+    private static readonly JsonSerializerOptions DiceJsonOptions = RpgRollerJson.CreateSerializerOptions();
     private readonly Dictionary<Guid, Campaign> m_CampaignsById = [];
     private readonly Dictionary<Guid, CampaignStateTracker> m_CampaignStateById = [];
     private readonly Dictionary<Guid, Character> m_CharactersById = [];