Domain blocks: suspend, silence, reject media

DomainBlock (domain, severity, reject-media, public and private comment)
covers the domain and its subdomains. Admins manage them under
/clientapi/admin/domainblocks/{list,insert,delete}; the set is kept in
memory, reloaded on every change and at most five minutes stale.

A suspended domain is refused by FederationHttp.IsAllowed, so nothing is
fetched from it and no job delivers to it, and the inbox drops its
activities with a 202 before fetching any key. Reject-media strips the
attachments of posts from that domain. Silence is recorded for the
timelines and notifications that arrive in P1.2.

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

PrivaPub/Controllers/ClientToServer/DomainBlockController.cs

@@ -0,0 +1,74 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Localization;
+
+using MongoDB.Entities;
+
+using PrivaPub.ClientModels;
+using PrivaPub.ClientModels.Admin;
+using PrivaPub.Federation.Moderation;
+using PrivaPub.Models.Federation;
+using PrivaPub.Resources;
+
+namespace PrivaPub.Controllers.ClientToServer
+{
+	[ApiController,
+		Route("clientapi/admin/domainblocks"),
+		Authorize(Policy = Policies.IsAdmin)]
+	public class DomainBlockController : ControllerBase
+	{
+		readonly IDomainBlocks _domainBlocks;
+		readonly IStringLocalizer _localizer;
+
+		public DomainBlockController(IDomainBlocks domainBlocks, IStringLocalizer<GenericRes> localizer)
+		{
+			_domainBlocks = domainBlocks;
+			_localizer = localizer;
+		}
+
+		[HttpGet, Route("/clientapi/admin/domainblocks/list")]
+		public async Task<IActionResult> List(CancellationToken token) =>
+			Ok((await DB.Default.Find<DomainBlock>().Sort(b => b.Domain, Order.Ascending).ExecuteAsync(token)).Select(ToView).ToList());
+
+		[HttpPost, Route("/clientapi/admin/domainblocks/insert")]
+		public async Task<IActionResult> Insert(DomainBlockForm form, CancellationToken token)
+		{
+			var domain = DomainBlocks.Normalise(form.Domain);
+			if (!ModelState.IsValid || Uri.CheckHostName(domain) != UriHostNameType.Dns)
+				return BadRequest(new WebResult().Invalidate(_localizer["Invalid model."]));
+
+			var block = await DB.Default.UpdateAndGet<DomainBlock>()
+				.Match(b => b.Domain == domain)
+				.Modify(b => b.Domain, domain)
+				.Modify(b => b.Severity, form.Suspend ? DomainBlockSeverity.Suspend : DomainBlockSeverity.Silence)
+				.Modify(b => b.RejectMedia, form.RejectMedia)
+				.Modify(b => b.PublicComment, form.PublicComment)
+				.Modify(b => b.PrivateComment, form.PrivateComment)
+				.Modify(b => b.SetOnInsert(x => x.CreatedAt, DateTime.UtcNow))
+				.Option(o => o.IsUpsert = true)
+				.ExecuteAsync(token);
+			await _domainBlocks.Reload(token);
+			return Ok(ToView(block));
+		}
+
+		[HttpPost, Route("/clientapi/admin/domainblocks/delete")]
+		public async Task<IActionResult> Delete([FromQuery] string domain, CancellationToken token)
+		{
+			domain = DomainBlocks.Normalise(domain);
+			await DB.Default.DeleteAsync<DomainBlock>(b => b.Domain == domain);
+			await _domainBlocks.Reload(token);
+			return Ok();
+		}
+
+		static ViewDomainBlock ToView(DomainBlock block) => new()
+		{
+			Id = block.ID,
+			Domain = block.Domain,
+			Severity = block.Severity.ToString(),
+			RejectMedia = block.RejectMedia,
+			PublicComment = block.PublicComment,
+			PrivateComment = block.PrivateComment,
+			CreatedAt = block.CreatedAt
+		};
+	}
+}