SocialPub/PrivaPub.Tests/Infrastructure/CdnCatalogTests.cs

using PrivaPub.Infrastructure.Geo;
using PrivaPub.Infrastructure.Http;
using PrivaPub.Models.Jobs;

using System.Net;

namespace PrivaPub.Tests.Infrastructure
{
	public class CdnCatalogTests
	{
		static HttpResponseMessage Response(params (string Name, string Value)[] headers)
		{
			var response = new HttpResponseMessage(HttpStatusCode.OK) { Content = new StringContent("{}") };
			foreach (var (name, value) in headers)
				response.Headers.TryAddWithoutValidation(name, value);
			return response;
		}

		[Theory]
		[InlineData("cf-ray", "8c1f0e2b4d5a1234-FRA", "cloudflare.com")]
		[InlineData("server", "cloudflare", "cloudflare.com")]
		[InlineData("x-amz-cf-id", "abc==", "cloudfront.net")]
		[InlineData("via", "1.1 5a1b.cloudfront.net (CloudFront)", "cloudfront.net")]
		[InlineData("x-served-by", "cache-fra-eddf8230045-FRA", "fastly.com")]
		[InlineData("server", "BunnyCDN-DE1-1078", "bunny.net")]
		[InlineData("akamai-grn", "0.1234", "akamai.com")]
		[InlineData("x-azure-ref", "20261004T101010Z-abc", "azure.microsoft.com")]
		[InlineData("x-vercel-id", "fra1::abc", "vercel.com")]
		[InlineData("x-iinfo", "1-2-3", "imperva.com")]
		public void A_cdn_is_recognised_by_its_fingerprint(string header, string value, string domain)
		{
			Assert.Equal(domain, CdnCatalog.FromResponse(Response((header, value)))?.Domain);
		}

		[Fact]
		public void A_plain_server_has_no_cdn_and_an_unknown_cdn_names_itself()
		{
			Assert.Null(CdnCatalog.FromResponse(Response(("server", "nginx"), ("via", "1.1 varnish"))));
			var named = CdnCatalog.FromResponse(Response(("x-cdn", "EdgeOne")));
			Assert.Equal(("EdgeOne", null, "edgeone"), (named.Name, named.Domain, named.Key));
			Assert.Null(CdnCatalog.FromResponse(Response(("x-cdn", "<script>"))));
		}

		[Fact]
		public void Only_networks_that_carry_nothing_but_a_cdn_name_it()
		{
			Assert.Equal("Cloudflare", CdnCatalog.OfAsn(13335)?.Name);
			Assert.Equal("Akamai", CdnCatalog.OfAsn(20940)?.Name);
			Assert.Null(CdnCatalog.OfAsn(16509));//AWS: CloudFront only by its ranges or its headers
			Assert.Null(CdnCatalog.OfAsn(60068));//DataPacket also rents servers
		}

		[Fact]
		public void Every_published_list_format_is_read()
		{
			Assert.Equal(new[] { "173.245.48.0/20", "2400:cb00::/32" },
				CdnCatalog.Parse(CdnListFormat.Lines, "173.245.48.0/20\n# comment\n\n2400:cb00::/32\n").Select(n => n.ToString()));
			Assert.Equal(new[] { "89.187.188.227/32", "2400:52e0:1500::714:1/128" },
				CdnCatalog.Parse(CdnListFormat.StringArray, """["89.187.188.227","2400:52e0:1500::714:1"]""").Select(n => n.ToString()));
			Assert.Equal(new[] { "23.235.32.0/20", "2a04:4e40::/32" },
				CdnCatalog.Parse(CdnListFormat.AddressesJson, """{"addresses":["23.235.32.0/20"],"ipv6_addresses":["2a04:4e40::/32"]}""").Select(n => n.ToString()));
			Assert.Equal(new[] { "92.223.124.12/32", "2a03:90c0::/32" },
				CdnCatalog.Parse(CdnListFormat.AddressesJson, """{"addresses":["92.223.124.12/32"],"addresses_v6":["2a03:90c0::/32"]}""").Select(n => n.ToString()));
			Assert.Equal(new[] { "199.83.128.0/21", "2a02:e980::/29" },
				CdnCatalog.Parse(CdnListFormat.ImpervaJson, """{"ipRanges":["199.83.128.0/21"],"ipv6Ranges":["2a02:e980::/29"],"res":0}""").Select(n => n.ToString()));
			Assert.Equal(new[] { "13.32.0.0/15", "2600:9000::/28" },
				CdnCatalog.Parse(CdnListFormat.AwsCloudFront, """
					{"prefixes":[{"ip_prefix":"3.4.12.4/32","service":"AMAZON"},{"ip_prefix":"13.32.0.0/15","service":"CLOUDFRONT"}],
					 "ipv6_prefixes":[{"ipv6_prefix":"2600:9000::/28","service":"CLOUDFRONT"},{"ipv6_prefix":"2406:daba::/40","service":"EC2"}]}
					""").Select(n => n.ToString()));
			Assert.Throws<FormatException>(() => CdnCatalog.Parse(CdnListFormat.Lines, "173.245.48.0/20\nnot an address"));
		}

		[Fact]
		public void The_published_ranges_name_the_cdn_of_an_address()
		{
			var ranges = new CdnRanges();
			ranges.Replace(new CdnRangeSet { Key = "cloudflare.com", Name = "Cloudflare", Ranges = new() { "104.16.0.0/13", "2606:4700::/32" }, FetchedAt = DateTime.UtcNow });

			Assert.Equal("Cloudflare", ranges.Of(IPAddress.Parse("104.18.2.3"))?.Name);
			Assert.Equal("Cloudflare", ranges.Of(IPAddress.Parse("::ffff:104.18.2.3"))?.Name);
			Assert.Equal("Cloudflare", ranges.Of(IPAddress.Parse("2606:4700::1"))?.Name);
			Assert.Null(ranges.Of(IPAddress.Parse("203.0.113.7")));
			Assert.Equal(2, ranges.Status["cloudflare.com"].Ranges);
		}

		[Fact]
		public async Task Responses_leave_a_cdn_hint_for_their_host_until_one_comes_without()
		{
			var hints = new EdgeHints();
			var answers = new Queue<HttpResponseMessage>(new[] { Response(("cf-ray", "1-FRA")), Response(("server", "nginx")) });
			using var client = new HttpClient(new EdgeHintsHandler(hints) { InnerHandler = new Answering(answers) });

			await client.GetAsync("https://social.example/.well-known/nodeinfo", TestContext.Current.CancellationToken);
			Assert.Equal("Cloudflare", hints.Of("social.example")?.Name);

			await client.GetAsync("https://social.example/nodeinfo/2.1", TestContext.Current.CancellationToken);
			Assert.Null(hints.Of("social.example"));
		}

		sealed class Answering : HttpMessageHandler
		{
			readonly Queue<HttpResponseMessage> _answers;

			public Answering(Queue<HttpResponseMessage> answers) => _answers = answers;

			protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) =>
				Task.FromResult(_answers.Dequeue());
		}
	}
}