Persona separation is tested, the API is smoke-checked on deploy, OAuth rows are pruned

- PersonaSeparationTests: two personas of one login follow the same
  account and post; nothing the API maps for one contains the other's id,
  username or the root id.
- tools/smoke/mastodon-api.sh checks what a client meets first (instance
  v1/v2, discovery, app registration, client credentials, an app token
  refused by a user endpoint, the public timeline, revocation) and, given
  a persona token, verify_credentials, home and notifications. deploy.yml
  runs it after every deploy.
- OAuthPruner removes invalid tokens and authorizations older than two
  weeks, every six hours.
- The consent page no longer sets form-action, which browsers apply to the
  redirect back to the client after the form is posted.

CLAUDE.md gains the Mastodon API layout and invariants.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB

.gitea/workflows/deploy.yml

@@ -104,4 +104,5 @@ jobs:
           code=$(curl -s -o /dev/null -w '%{http_code}' -X POST -H 'Content-Type: application/activity+json' \
             --data '{"type":"Follow","actor":"https://example.org/users/x","object":"'"$PUBLIC_URL"'/peasants/privapub"}' "$PUBLIC_URL/human-centipede")
           [ "$code" = "401" ] || { echo "::error::an unsigned inbox POST answered $code"; exit 1; }
+          tools/smoke/mastodon-api.sh "$PUBLIC_URL"
           echo "::notice::serving $served"

CLAUDE.md

@@ -90,7 +90,14 @@ PrivaPub/                         ASP.NET Core Web API, net10.0
     Social/                       FollowService (local in-process, remote Follow/Accept), Notifications
     Timelines/                    Fanout (TimelineEntry rows, Mastodon's home rules), TimelineService
     Privacy/                      VisibilityPolicy (IsPublic expression, CanSee)
-  Web/Pages/                      Razor: /@{user}, /@{user}/{id} (public posts only, strict CSP, noindex)
+  Domain/Statuses/                StatusService: publish, edit, remove, favourite, reblog, for a persona (both client APIs use it)
+  Api/Mastodon/
+    Auth/                         OpenIddict setup (keys in Mongo), MastodonScopes, TokenController, OAuthPruner
+    Infrastructure/               MastodonController (avatar context, scopes, errors, Link), MastodonParams, MastodonJson, Page
+    Entities/ Mappers/            Mastodon entities; MastodonMapper (Account, Status), AccountSearch
+    Controllers/                  apps, instance, accounts, statuses, timelines, notifications, search, stubs
+  Web/Pages/                      Razor: /@{user}, /@{user}/{id} (public posts only, strict CSP, noindex);
+                                  OAuth/: /oauth/login (root password), /oauth/authorize (choose persona, consent)
   Services/                       RootUsersService, GroupUsersService, PostsService, AppConfigurationService, …
   Models/                         Mongo entities: User/, Group/, Post/, Federation/, Jobs/, AppConfiguration
   StaticServices/                 DbEntities (Find<T> accessors), AuthTokenManager (JWT), PasswordHasher
@@ -171,6 +178,18 @@ cd /var/www/privapub.thepra.dev && sudo -u www-data ASPNETCORE_ENVIRONMENT=Produ
 13. **Home timelines are written, not computed:** every stored or created post goes through `Fanout.Distribute`, and
     every delete removes its `TimelineEntry` rows. Local deletes are soft (content cleared, 410 Tombstone).
 
+## Mastodon client API invariants
+
+1. **A token is one persona.** Its subject is the avatar id; the root id lives only in the fifteen-minute `/oauth`
+   cookie used while choosing the persona, and never in a token, an authorization or a response.
+2. `/api/*` authenticates with OpenIddict validation, everything else with the old JWT (`PrivaPub` policy scheme).
+   Every `/api` request re-checks that the persona's root is neither banned nor deleted (`MastodonController`).
+3. Read parameters through `Params` (query, form and JSON merged Rails-style), never MVC binding. A value type read
+   from a conditional must say `(int?)null`, not `default`: that bug once made every list one item long.
+4. Answer with `Json(...)` (snake_case, explicit nulls) or `Error(status, message)`; page lists with `Page` and `Link`.
+5. Unsupported features answer empty lists or 422 with a message, never 404 or 500, so clients degrade.
+6. Advertise `4.2.0 (compatible; PrivaPub)` until grouped notifications exist.
+
 ## Privacy invariants
 
 - **No root id in federation output, NodeInfo or logs, no IP next to an identity in logs, and no `ex.Message` to a
@@ -233,7 +252,8 @@ the owner's GoToSocial at social.arasaka.software. **Ask before acting from the
 - **CI/CD:** push to `master` runs `build.yml` (build + tests) on the instance-wide `build` runner. A `v*` tag runs
   `deploy.yml`: tests, self-contained linux-x64 publish, snapshot and `mongodump` to `/var/backups/privapub.thepra.dev`,
   stop → rsync → start, a `127.0.0.1:6970/build.json` health loop with rollback, then public checks (actor, NodeInfo,
-  Swagger 404, inbox junk 400, unsigned 401).
+  Swagger 404, inbox junk 400, unsigned 401) and `tools/smoke/mastodon-api.sh` (app registration, client credentials,
+  discovery, instance, public timeline; pass a persona token as a second argument to check the signed-in side).
 - **The box:** Max (`nuvola.xyz`). Unit `privapub` runs as www-data from `/var/www/privapub.thepra.dev` with
   `ASPNETCORE_ENVIRONMENT=Production`.
 - **One-time root setup:** `deploy/max/setup.sh`, run through `../arasaka.software/tools/max/run.sh`.

PrivaPub.Tests/Api/PersonaSeparationTests.cs

@@ -0,0 +1,61 @@
+using Microsoft.Extensions.Caching.Memory;
+
+using MongoDB.Entities;
+
+using PrivaPub.Api.Mastodon.Infrastructure;
+using PrivaPub.Api.Mastodon.Mappers;
+using PrivaPub.ClientModels.Post;
+using PrivaPub.ClientModels.Social;
+using PrivaPub.Models.Post;
+using PrivaPub.Tests.Support;
+
+using System.Text.Json;
+
+namespace PrivaPub.Tests.Api
+{
+	[Trait("Category", "Integration")]
+	public sealed class PersonaSeparationTests : IAsyncLifetime
+	{
+		Harness _harness;
+
+		public async ValueTask InitializeAsync()
+		{
+			Assert.SkipUnless(MongoFixture.Enabled, MongoFixture.Skip);
+			_harness = await Harness.Start();
+		}
+
+		public async ValueTask DisposeAsync()
+		{
+			if (_harness != default)
+				await _harness.DisposeAsync();
+		}
+
+		[Fact]
+		public async Task Nothing_shown_to_one_persona_names_its_sibling()
+		{
+			var token = TestContext.Current.CancellationToken;
+			var (root, alice) = await _harness.Persona("alice");
+			var (_, sibling) = await _harness.Persona("sibling", root);
+			var (bobRoot, bob) = await _harness.Persona("bob");
+			await _harness.Follows.Follow(root, new FollowForm { AvatarId = alice.Id, Target = bob.UserName }, token);
+			await _harness.Follows.Follow(root, new FollowForm { AvatarId = sibling.Id, Target = bob.UserName }, token);
+			await _harness.Posts.InsertPost(root, new InsertPostForm { AvatarId = sibling.Id, Text = "from the sibling" }, token);
+			await _harness.Posts.InsertPost(root, new InsertPostForm { AvatarId = alice.Id, Text = "from alice" }, token);
+			await _harness.Posts.InsertPost(bobRoot, new InsertPostForm { AvatarId = bob.Id, Text = "hi both" }, token);
+
+			var mapper = new MastodonMapper(_harness.Db, _harness.Local);
+			var account = await mapper.Local(alice, withSource: true, token);
+			var homeIds = (await _harness.Db.TimelineEntries.Match(e => e.AvatarId == alice.Id).ExecuteAsync(token)).Select(e => e.PostId).ToList();
+			var home = await _harness.Db.Posts.Match(p => homeIds.Contains(p.ID)).ExecuteAsync(token);
+			var statuses = await mapper.Statuses(home, alice.Id, token);
+			var bobAsSeenByAlice = await mapper.Account(bob.Id, token);
+
+			var json = JsonSerializer.Serialize(new object[] { account, statuses, bobAsSeenByAlice }, MastodonJson.Options);
+			Assert.DoesNotContain(sibling.Id, json);
+			Assert.DoesNotContain(sibling.UserName, json);
+			Assert.DoesNotContain(root, json);
+			Assert.Contains("hi both", json);
+			Assert.Equal(2, bobAsSeenByAlice.FollowersCount);
+		}
+	}
+}

PrivaPub/Api/Mastodon/Auth/OAuthPruner.cs

@@ -0,0 +1,44 @@
+using OpenIddict.Abstractions;
+
+namespace PrivaPub.Api.Mastodon.Auth
+{
+	public class OAuthPruner : BackgroundService
+	{
+		static readonly TimeSpan Interval = TimeSpan.FromHours(6);
+		static readonly TimeSpan Threshold = TimeSpan.FromDays(14);
+
+		readonly IServiceProvider _services;
+		readonly ILogger<OAuthPruner> _logger;
+
+		public OAuthPruner(IServiceProvider services, ILogger<OAuthPruner> logger)
+		{
+			_services = services;
+			_logger = logger;
+		}
+
+		protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+		{
+			while (!stoppingToken.IsCancellationRequested)
+			{
+				try
+				{
+					await Task.Delay(Interval, stoppingToken);
+					using var scope = _services.CreateScope();
+					var threshold = DateTimeOffset.UtcNow - Threshold;
+					var tokens = await scope.ServiceProvider.GetRequiredService<IOpenIddictTokenManager>().PruneAsync(threshold, stoppingToken);
+					var authorizations = await scope.ServiceProvider.GetRequiredService<IOpenIddictAuthorizationManager>().PruneAsync(threshold, stoppingToken);
+					if (tokens + authorizations > 0)
+						_logger.LogInformation("{Service} removed {Tokens} tokens and {Authorizations} authorizations", nameof(OAuthPruner), tokens, authorizations);
+				}
+				catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
+				{
+					return;
+				}
+				catch (Exception ex)
+				{
+					_logger.LogWarning(ex, "{Service} pass failed", nameof(OAuthPruner));
+				}
+			}
+		}
+	}
+}

PrivaPub/Api/Mastodon/Auth/OAuthSetup.cs

@@ -26,6 +26,7 @@ namespace PrivaPub.Api.Mastodon.Auth
 		public static IServiceCollection PrivaPubOAuth(this IServiceCollection services, IWebHostEnvironment environment)
 		{
 			services.AddSingleton<IMongoDatabase>(_ => DB.Default.Database());
+			services.AddHostedService<OAuthPruner>();
 
 			services.AddAuthentication()
 				.AddCookie(LoginScheme, options =>

PrivaPub/Web/Pages/OAuth/OAuthPages.cs

@@ -147,7 +147,7 @@ namespace PrivaPub.Web.Pages.OAuth
 				.Where(p => p.Key is not ("avatarId" or "decision" or "signed_in"))
 				.Select(p => new KeyValuePair<string, string>(p.Key, (string)p.Value))
 				.ToList();
-			Response.Headers["Content-Security-Policy"] = "default-src 'none'; style-src 'unsafe-inline'; form-action 'self'; frame-ancestors 'none'";
+			Response.Headers["Content-Security-Policy"] = "default-src 'none'; style-src 'unsafe-inline'; frame-ancestors 'none'";
 			Response.Headers["Cache-Control"] = "no-store";
 			return Page();
 		}

tools/smoke/mastodon-api.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+# Checks the Mastodon client API the way a client first meets it.
+# usage: tools/smoke/mastodon-api.sh https://privapub.thepra.dev [ACCESS_TOKEN]
+set -euo pipefail
+BASE="${1:?base url}"; TOKEN="${2:-}"
+fail() { echo "::error::$*"; exit 1; }
+json() { python3 -c "import sys,json; d=json.load(sys.stdin); $1"; }
+
+version=$(curl -fsS "$BASE/api/v1/instance" | json "print(d['version'])") || fail "instance v1"
+curl -fsS "$BASE/api/v2/instance" | json "assert d['configuration']['statuses']['max_characters'] > 0" || fail "instance v2"
+curl -fsS "$BASE/.well-known/oauth-authorization-server" | json "assert d['token_endpoint'].endswith('/oauth/token')" || fail "oauth discovery"
+
+app=$(curl -fsS -X POST "$BASE/api/v1/apps" -d 'client_name=privapub-smoke&redirect_uris=urn:ietf:wg:oauth:2.0:oob&scopes=read') || fail "app registration"
+id=$(echo "$app" | json "print(d['client_id'])"); secret=$(echo "$app" | json "print(d['client_secret'])")
+app_token=$(curl -fsS -X POST "$BASE/oauth/token" -d "grant_type=client_credentials&client_id=$id&client_secret=$secret&scope=read" | json "print(d['access_token'])") || fail "client credentials"
+curl -fsS -H "Authorization: Bearer $app_token" "$BASE/api/v1/apps/verify_credentials" | json "assert d['name'] == 'privapub-smoke'" || fail "app verify_credentials"
+code=$(curl -s -o /dev/null -w '%{http_code}' -H "Authorization: Bearer $app_token" "$BASE/api/v1/accounts/verify_credentials")
+[ "$code" = "401" ] || fail "an app token reached a user endpoint ($code)"
+curl -fsS "$BASE/api/v1/timelines/public?limit=2" | json "assert isinstance(d, list)" || fail "public timeline"
+curl -fsS -X POST "$BASE/oauth/revoke" -d "token=$app_token&client_id=$id&client_secret=$secret" -o /dev/null || fail "revoke"
+
+if [ -n "$TOKEN" ]; then
+	curl -fsS -H "Authorization: Bearer $TOKEN" "$BASE/api/v1/accounts/verify_credentials" | json "assert d['source'] is not None" || fail "verify_credentials"
+	curl -fsS -H "Authorization: Bearer $TOKEN" "$BASE/api/v1/timelines/home?limit=5" | json "assert isinstance(d, list)" || fail "home"
+	curl -fsS -H "Authorization: Bearer $TOKEN" "$BASE/api/v1/notifications?limit=5" | json "assert isinstance(d, list)" || fail "notifications"
+fi
+echo "mastodon api ok: $version"