Add news post type with list and detail routes

Elternbeirat.Web/Services/FrontMatter.cs

@@ -0,0 +1,42 @@
+using Markdig;
+using Markdig.Extensions.Yaml;
+using Markdig.Syntax;
+
+namespace Elternbeirat.Web.Services;
+
+/// <summary>
+/// Reads simple <c>key: value</c> pairs from a Markdown file's YAML front
+/// matter. Kept deliberately minimal (one value per line, no nesting) — this is
+/// enough for titles and dates. YamlDotNet will take over once we need
+/// structured metadata. Front-matter keys stay German because the Markdown
+/// files are edited by German-speaking editors.
+/// </summary>
+public static class FrontMatter
+{
+    /// <summary>
+    /// Returns the value of the given front-matter key, or <c>null</c> if the
+    /// file has no front matter or the key is missing. The key match is
+    /// case-insensitive; surrounding quotes on the value are removed.
+    /// </summary>
+    public static string? Read(string key, MarkdownDocument document, string source)
+    {
+        var block = document.Descendants<YamlFrontMatterBlock>().FirstOrDefault();
+        if (block is null)
+        {
+            return null;
+        }
+
+        var prefix = key + ":";
+        var frontMatter = source.Substring(block.Span.Start, block.Span.Length);
+        foreach (var line in frontMatter.Split('\n'))
+        {
+            var trimmed = line.Trim();
+            if (trimmed.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
+            {
+                return trimmed[prefix.Length..].Trim().Trim('"');
+            }
+        }
+
+        return null;
+    }
+}

Elternbeirat.Web/Services/PageService.cs

@@ -1,6 +1,4 @@
 using Markdig;
-using Markdig.Extensions.Yaml;
-using Markdig.Syntax;
 
 namespace Elternbeirat.Web.Services;
 
@@ -51,36 +49,9 @@ public sealed class PageService
         var source = File.ReadAllText(path);
 
         var document = Markdown.Parse(source, pipeline);
-        var title = ReadTitle(document, source) ?? slug;
+        var title = FrontMatter.Read("titel", document, source) ?? slug;
         var html = Markdown.ToHtml(source, pipeline);
 
         return new Page { Slug = slug, Title = title, ContentHtml = html };
     }
-
-    /// <summary>
-    /// Pulls the <c>titel:</c> value out of the YAML front matter. Kept
-    /// deliberately simple (a single <c>key: value</c> line) — YamlDotNet will
-    /// take over once we need structured metadata. The key stays German because
-    /// the Markdown files are edited by German-speaking editors.
-    /// </summary>
-    private static string? ReadTitle(MarkdownDocument document, string source)
-    {
-        var block = document.Descendants<YamlFrontMatterBlock>().FirstOrDefault();
-        if (block is null)
-        {
-            return null;
-        }
-
-        var frontMatter = source.Substring(block.Span.Start, block.Span.Length);
-        foreach (var line in frontMatter.Split('\n'))
-        {
-            var trimmed = line.Trim();
-            if (trimmed.StartsWith("titel:", StringComparison.OrdinalIgnoreCase))
-            {
-                return trimmed["titel:".Length..].Trim().Trim('"');
-            }
-        }
-
-        return null;
-    }
 }

Elternbeirat.Web/Services/Post.cs

@@ -0,0 +1,33 @@
+namespace Elternbeirat.Web.Services;
+
+/// <summary>
+/// A news post ("Beitrag"), read from a Markdown file in
+/// <c>Content/beitraege/</c>. Unlike a <see cref="Page"/>, a post has a date and
+/// is shown in a chronological list. The file name (without extension) is the
+/// slug.
+/// </summary>
+public sealed class Post
+{
+    /// <summary>
+    /// URL identifier of the post, taken from the file name without umlauts.
+    /// It appears in the route <c>/beitraege/{slug}</c>.
+    /// </summary>
+    public required string Slug { get; init; }
+
+    /// <summary>
+    /// Display title from the YAML front matter (<c>titel:</c>). Falls back to
+    /// the slug when no title is set.
+    /// </summary>
+    public required string Title { get; init; }
+
+    /// <summary>
+    /// Publication date from the front matter (<c>datum:</c>). Used to sort the
+    /// list newest first.
+    /// </summary>
+    public required DateOnly Date { get; init; }
+
+    /// <summary>
+    /// The post body rendered from Markdown to HTML (front matter excluded).
+    /// </summary>
+    public required string ContentHtml { get; init; }
+}

Elternbeirat.Web/Services/PostService.cs

@@ -0,0 +1,86 @@
+using System.Globalization;
+using Markdig;
+
+namespace Elternbeirat.Web.Services;
+
+/// <summary>
+/// Reads the news posts from <c>Content/beitraege/*.md</c>, renders them to HTML
+/// once at startup and keeps them in memory, sorted newest first. Registered as
+/// a singleton because the content lives in the image and does not change at
+/// runtime.
+/// </summary>
+public sealed class PostService
+{
+    private readonly IReadOnlyList<Post> _posts;
+    private readonly IReadOnlyDictionary<string, Post> _postsBySlug;
+
+    /// <summary>
+    /// Reads every Markdown post from the <c>Content/beitraege</c> directory
+    /// below the application root and caches it.
+    /// </summary>
+    public PostService(IWebHostEnvironment environment)
+    {
+        var pipeline = new MarkdownPipelineBuilder()
+            .UseYamlFrontMatter()
+            .Build();
+
+        var directory = Path.Combine(environment.ContentRootPath, "Content", "beitraege");
+        var posts = new List<Post>();
+
+        if (Directory.Exists(directory))
+        {
+            foreach (var path in Directory.EnumerateFiles(directory, "*.md"))
+            {
+                posts.Add(Read(path, pipeline));
+            }
+        }
+
+        // Newest first for the list; a stable slug order breaks date ties.
+        posts.Sort((a, b) =>
+        {
+            var byDate = b.Date.CompareTo(a.Date);
+            return byDate != 0 ? byDate : string.CompareOrdinal(a.Slug, b.Slug);
+        });
+
+        _posts = posts;
+        _postsBySlug = posts.ToDictionary(p => p.Slug, StringComparer.OrdinalIgnoreCase);
+    }
+
+    /// <summary>
+    /// All posts, newest first. Used for the overview list.
+    /// </summary>
+    public IReadOnlyList<Post> All => _posts;
+
+    /// <summary>
+    /// Returns the post for the given slug, or <c>null</c> if there is none.
+    /// The lookup is case-insensitive.
+    /// </summary>
+    public Post? Find(string slug) =>
+        _postsBySlug.GetValueOrDefault(slug);
+
+    private static Post Read(string path, MarkdownPipeline pipeline)
+    {
+        var slug = Path.GetFileNameWithoutExtension(path);
+        var source = File.ReadAllText(path);
+
+        var document = Markdown.Parse(source, pipeline);
+        var title = FrontMatter.Read("titel", document, source) ?? slug;
+        var date = ParseDate(FrontMatter.Read("datum", document, source));
+        var html = Markdown.ToHtml(source, pipeline);
+
+        return new Post { Slug = slug, Title = title, Date = date, ContentHtml = html };
+    }
+
+    /// <summary>
+    /// Parses the <c>datum:</c> value as an ISO date (yyyy-MM-dd). Falls back to
+    /// <see cref="DateOnly.MinValue"/> when the value is missing or malformed,
+    /// so a single bad file does not crash startup — it just sorts last.
+    /// </summary>
+    private static DateOnly ParseDate(string? value)
+    {
+        return DateOnly.TryParse(value, CultureInfo.InvariantCulture,
+            DateTimeStyles.None, out var date)
+            ? date
+            : DateOnly.MinValue;
+    }
+}