From 105b2069f45a3a35cd394d80329bb6c9c82651fa Mon Sep 17 00:00:00 2001
From: Laura Hausmann <laura@hausmann.dev>
Date: Sat, 26 Nov 2022 15:51:29 +0100
Subject: [PATCH] Add Atom feed

---
 Backend/Utils.cs        | 19 ++++++++++++++++++-
 Controllers/AtomFeed.cs | 35 +++++++++++++++++++++++++++++++++++
 zotan.pw-web.csproj     |  1 +
 3 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 Controllers/AtomFeed.cs

diff --git a/Backend/Utils.cs b/Backend/Utils.cs
index e1beea2..c81fc2b 100644
--- a/Backend/Utils.cs
+++ b/Backend/Utils.cs
@@ -1,4 +1,7 @@
 using System.Reflection;
+using System.ServiceModel.Syndication;
+using System.Text;
+using System.Xml;
 
 namespace zotanpw.Backend;
 
@@ -21,4 +24,18 @@ public static class Utils {
 			_  => "a"
 		};
 	}
-}
\ No newline at end of file
+
+	public static string ToXmlString(this SyndicationFeedFormatter feed) {
+		using var sw = new StringWriterWithEncoding(Encoding.UTF8);
+		using (var xw = XmlWriter.Create(sw, new XmlWriterSettings { Encoding = Encoding.UTF8 }))
+			feed.WriteTo(xw);
+
+		return sw.ToString();
+	}
+
+	private sealed class StringWriterWithEncoding : StringWriter {
+		public StringWriterWithEncoding(Encoding encoding) => Encoding = encoding;
+
+		public override Encoding Encoding { get; }
+	}
+}
diff --git a/Controllers/AtomFeed.cs b/Controllers/AtomFeed.cs
new file mode 100644
index 0000000..2260b4c
--- /dev/null
+++ b/Controllers/AtomFeed.cs
@@ -0,0 +1,35 @@
+using System.ServiceModel.Syndication;
+using Microsoft.AspNetCore.Mvc;
+using zotanpw.Backend;
+using zotanpw.Pages.blog;
+
+namespace zotanpw.Controllers;
+
+[ApiController]
+public class AtomFeed : Controller {
+	private static readonly string AtomXml;
+
+	static AtomFeed() {
+		var feed = new SyndicationFeed {
+			Id              = "https://zotan.pw/blog",
+			Title           = new TextSyndicationContent("zotan.pw >> blog"),
+			Description     = new TextSyndicationContent("Blog of a disabled neurodivergent queer person unhappy with the state of the world"),
+			LastUpdatedTime = DateTimeOffset.Now,
+			Authors         = { new SyndicationPerson("zotan@zotan.pw", "zotan", "https://zotan.pw") },
+			Items = BlogModel.Posts.Take(10)
+							 .Select(post => new SyndicationItem(post.Title, new TextSyndicationContent(post.Content, TextSyndicationContentKind.Html),
+														         new Uri($"https://zotan.pw/blog/{post.Shorthand}"), $"https://zotan.pw/blog/{post.Shorthand}",
+														         post.PublishedOn.ToDateTime(TimeOnly.MinValue)))
+							 .ToList(),
+			Links = { SyndicationLink.CreateSelfLink(new Uri("https://zotan.pw/blog/feed.atom")) }
+		};
+
+		AtomXml = new Atom10FeedFormatter(feed).ToXmlString();
+	}
+
+	[HttpGet, Route("/blog/feed.atom")]
+	public ActionResult GetAtomFeed() {
+		Response.ContentType = "application/atom+xml";
+		return Content(AtomXml);
+	}
+}
diff --git a/zotan.pw-web.csproj b/zotan.pw-web.csproj
index 4c2ec9c..e532e8f 100644
--- a/zotan.pw-web.csproj
+++ b/zotan.pw-web.csproj
@@ -13,6 +13,7 @@
         <PackageReference Include="Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation" Version="7.0.0"/>
         <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="7.0.0"/>
         <PackageReference Include="System.Data.SQLite" Version="1.0.115"/>
+        <PackageReference Include="System.ServiceModel.Syndication" Version="7.0.0"/>
         <PackageReference Include="YamlDotNet" Version="12.0.2"/>
     </ItemGroup>