SocialPub/PrivaPub.Tests/Support/Peer.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Caching.Memory;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;

using PrivaPub.Federation.Moderation;
using PrivaPub.Infrastructure.Http;
using PrivaPub.Infrastructure.Statistics;
using PrivaPub.Models.Federation;

using System.Collections.Concurrent;

namespace PrivaPub.Tests.Support
{
	public sealed class Peer : IAsyncDisposable
	{
		readonly WebApplication _app;
		readonly ConcurrentDictionary<string, (string Text, string ContentType)> _documents = new();
		readonly ConcurrentDictionary<string, (int Status, TimeSpan Delay)> _answers = new();
		readonly ConcurrentDictionary<string, (byte[] Bytes, string ContentType)> _files = new();
		readonly ConcurrentDictionary<string, string> _etags = new();

		public int Port { get; }
		public string A => $"http://127.0.0.1:{Port}";
		public string B => $"http://localhost:{Port}";
		public ConcurrentQueue<HttpRequestRecord> Requests { get; } = new();

		Peer(WebApplication app, int port)
		{
			_app = app;
			Port = port;
		}

		public static async Task<Peer> Start()
		{
			var builder = WebApplication.CreateSlimBuilder();
			builder.WebHost.UseUrls("http://127.0.0.1:0");
			var app = builder.Build();
			Peer peer = default;
			app.Run(async context =>
			{
				var body = context.Request.ContentLength > 0 || context.Request.Headers.TransferEncoding.Count > 0
					? await new StreamReader(context.Request.Body).ReadToEndAsync()
					: default;
				peer.Requests.Enqueue(new(context.Request.Method, context.Request.Path, context.Request.Headers["Signature"].ToString(), body,
					context.Request.Headers.ToDictionary(h => h.Key, h => h.Value.ToString(), StringComparer.OrdinalIgnoreCase)));
				var key = context.Request.Path.Value;
				if (peer._files.TryGetValue(key, out var file))
				{
					await Results.Bytes(file.Bytes, file.ContentType, enableRangeProcessing: true).ExecuteAsync(context);
					return;
				}
				if (peer._answers.TryGetValue(key, out var answer))
				{
					if (answer.Delay > TimeSpan.Zero)
						await Task.Delay(answer.Delay);
					context.Response.StatusCode = answer.Status;
					return;
				}
				if (!peer._documents.TryGetValue(key, out var document))
				{
					context.Response.StatusCode = StatusCodes.Status404NotFound;
					return;
				}
				if (peer._etags.TryGetValue(key, out var etag))
				{
					if (context.Request.Headers.IfNoneMatch.ToString() == etag)
					{
						context.Response.StatusCode = StatusCodes.Status304NotModified;
						return;
					}
					context.Response.Headers.ETag = etag;
				}
				context.Response.ContentType = document.ContentType;
				await context.Response.WriteAsync(document.Text.Replace("{A}", peer.A).Replace("{B}", peer.B));
			});
			await app.StartAsync();
			peer = new Peer(app, new Uri(app.Urls.First()).Port);
			return peer;
		}

		public void Serve(string path, string json) => _documents[path] = (json, "application/activity+json");

		// a document with an ETag: answered 304 to a request that names it in If-None-Match
		public void ServeTagged(string path, string json, string etag)
		{
			_documents[path] = (json, "application/activity+json");
			_etags[path] = etag;
		}

		public void ServeText(string path, string text, string contentType) => _documents[path] = (text, contentType);

		public void ServeFile(string path, byte[] bytes, string contentType) => _files[path] = (bytes, contentType);

		public void Answer(string path, int status, TimeSpan delay = default) => _answers[path] = (status, delay);

		public static FederationHttp Http(IMemoryCache cache = default, IDomainBlocks blocks = default, IInteractionLedger ledger = default,
			IConnectedAddresses connected = default)
		{
			var options = new FederationOptions { AllowPrivateNetworks = true, AllowPlainHttp = true };
			var services = new ServiceCollection();
			services.AddHttpClient(FederationHttp.ClientName)
				.ConfigurePrimaryHttpMessageHandler(() => SafeHttpHandlerFactory.Create(options, connected));
			return new FederationHttp(services.BuildServiceProvider().GetRequiredService<IHttpClientFactory>(),
				cache ?? new MemoryCache(new MemoryCacheOptions()), new StaticOptions<FederationOptions>(options),
				blocks ?? new NoBlocks(), NullLogger<FederationHttp>.Instance, ledger);
		}

		public async ValueTask DisposeAsync() => await _app.DisposeAsync();
	}

	public sealed class NoBlocks : IDomainBlocks
	{
		public DomainBlock Find(string host) => default;
		public bool IsSuspended(string host) => false;
		public Task Reload(CancellationToken token) => Task.CompletedTask;
	}

	public sealed record HttpRequestRecord(string Method, string Path, string Signature, string Body = default,
		IReadOnlyDictionary<string, string> Headers = default);

	public sealed class StaticOptions<T> : IOptionsMonitor<T>
	{
		public StaticOptions(T value) => CurrentValue = value;
		public T CurrentValue { get; }
		public T Get(string name) => CurrentValue;
		public IDisposable OnChange(Action<T, string> listener) => default;
	}
}