add: watch command.

YaeBlog.Core/Abstractions/IEssayContentService.cs

@@ -9,5 +9,14 @@ public interface IEssayContentService
 
     public IReadOnlyDictionary<EssayTag, List<BlogEssay>> Tags { get; }
 
-    public bool SearchByUrlEncodedTag(string tag,[NotNullWhen(true)] out List<BlogEssay>? result);
+    public IReadOnlyDictionary<string, BlogHeadline> Headlines { get; }
+
+    public bool TryAddHeadline(string filename, BlogHeadline headline);
+    public bool SearchByUrlEncodedTag(string tag, [NotNullWhen(true)] out List<BlogEssay>? result);
+
+    public bool TryAdd(BlogEssay essay);
+
+    public void RefreshTags();
+
+    public void Clear();
 }

YaeBlog.Core/Abstractions/ITableOfContentService.cs

@@ -1,8 +0,0 @@
-using YaeBlog.Core.Models;
-
-namespace YaeBlog.Core.Abstractions;
-
-public interface ITableOfContentService
-{
-    public IReadOnlyDictionary<string, BlogHeadline> Headlines { get; }
-}

YaeBlog.Core/Extensions/WebApplicationBuilderExtensions.cs

@@ -22,12 +22,7 @@ public static class WebApplicationBuilderExtensions
         builder.Services.AddSingleton<IConfiguration>(_ => Configuration.Default);
         builder.Services.AddSingleton<IEssayScanService, EssayScanService>();
         builder.Services.AddSingleton<RendererService>();
-        builder.Services.AddSingleton<EssayContentService>();
+        builder.Services.AddSingleton<IEssayContentService, EssayContentService>();
-        builder.Services.AddSingleton<IEssayContentService, EssayContentService>(provider =>
-            provider.GetRequiredService<EssayContentService>());
-        builder.Services.AddSingleton<TableOfContentService>();
-        builder.Services.AddSingleton<ITableOfContentService, TableOfContentService>(provider =>
-            provider.GetRequiredService<TableOfContentService>());
         builder.Services.AddTransient<ImagePostRenderProcessor>();
         builder.Services.AddTransient<CodeBlockPostRenderProcessor>();
         builder.Services.AddTransient<TablePostRenderProcessor>();
@@ -35,8 +30,21 @@ public static class WebApplicationBuilderExtensions
         builder.Services.AddTransient<BlogOptions>(provider =>
             provider.GetRequiredService<IOptions<BlogOptions>>().Value);
 
+        return builder;
+    }
+
+    public static WebApplicationBuilder AddServer(this WebApplicationBuilder builder)
+    {
         builder.Services.AddHostedService<BlogHostedService>();
 
         return builder;
     }
+
+    public static WebApplicationBuilder AddWatcher(this WebApplicationBuilder builder)
+    {
+        builder.Services.AddTransient<BlogChangeWatcher>();
+        builder.Services.AddHostedService<BlogHotReloadService>();
+
+        return builder;
+    }
 }

YaeBlog.Core/Processors/HeadlinePostRenderProcessor.cs

@@ -1,14 +1,15 @@
 using AngleSharp;
 using AngleSharp.Dom;
+using Microsoft.Extensions.Logging;
 using YaeBlog.Core.Abstractions;
 using YaeBlog.Core.Models;
-using YaeBlog.Core.Services;
 
 namespace YaeBlog.Core.Processors;
 
 public class HeadlinePostRenderProcessor(
     IConfiguration angleConfiguration,
-    TableOfContentService tableOfContentService) : IPostRenderProcessor
+    IEssayContentService essayContentService,
+    ILogger<HeadlinePostRenderProcessor> logger) : IPostRenderProcessor
 {
     public async Task<BlogEssay> ProcessAsync(BlogEssay essay)
     {
@@ -62,7 +63,10 @@ public class HeadlinePostRenderProcessor(
         FindParentHeadline(topHeadline, level2List).Children.AddRange(level3List);
         topHeadline.Children.AddRange(level2List);
 
-        tableOfContentService.AddHeadline(essay.FileName, topHeadline);
+        if (!essayContentService.TryAddHeadline(essay.FileName, topHeadline))
+        {
+            logger.LogWarning("Failed to add headline of {}.", essay.FileName);
+        }
 
         return essay.WithNewHtmlContent(document.DocumentElement.OuterHtml);
     }

YaeBlog.Core/Services/BlogChangeWatcher.cs

@@ -0,0 +1,61 @@
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using YaeBlog.Core.Models;
+
+namespace YaeBlog.Core.Services;
+
+public sealed class BlogChangeWatcher : IDisposable
+{
+    private readonly FileSystemWatcher _fileSystemWatcher;
+    private readonly ILogger<BlogChangeWatcher> _logger;
+
+    public BlogChangeWatcher(IOptions<BlogOptions> options, ILogger<BlogChangeWatcher> logger)
+    {
+        _logger = logger;
+        _fileSystemWatcher = new FileSystemWatcher(Path.Combine(Environment.CurrentDirectory, options.Value.Root));
+
+        _fileSystemWatcher.NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.FileName |
+                                          NotifyFilters.DirectoryName | NotifyFilters.Size;
+        _fileSystemWatcher.IncludeSubdirectories = true;
+        _fileSystemWatcher.EnableRaisingEvents = true;
+    }
+
+    public async Task<string?> WaitForChange(CancellationToken cancellationToken = default)
+    {
+        TaskCompletionSource<string?> tcs = new();
+        cancellationToken.Register(() => tcs.TrySetResult(null));
+
+        _logger.LogDebug("Register file change handle.");
+        _fileSystemWatcher.Changed += FileChangedCallback;
+        _fileSystemWatcher.Created += FileChangedCallback;
+        _fileSystemWatcher.Deleted += FileChangedCallback;
+        _fileSystemWatcher.Renamed += FileChangedCallback;
+
+        string? result;
+        try
+        {
+            result = await tcs.Task;
+        }
+        finally
+        {
+            _logger.LogDebug("Unregister file change handle.");
+            _fileSystemWatcher.Changed -= FileChangedCallback;
+            _fileSystemWatcher.Created -= FileChangedCallback;
+            _fileSystemWatcher.Deleted -= FileChangedCallback;
+            _fileSystemWatcher.Renamed -= FileChangedCallback;
+        }
+
+        return result;
+
+        void FileChangedCallback(object _, FileSystemEventArgs e)
+        {
+            _logger.LogDebug("File {} change detected.", e.Name);
+            tcs.TrySetResult(e.Name);
+        }
+    }
+
+    public void Dispose()
+    {
+        _fileSystemWatcher.Dispose();
+    }
+}

YaeBlog.Core/Services/BlogHotReloadService.cs

@@ -0,0 +1,35 @@
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using YaeBlog.Core.Abstractions;
+
+namespace YaeBlog.Core.Services;
+
+public sealed class BlogHotReloadService(
+    RendererService rendererService,
+    IEssayContentService essayContentService,
+    BlogChangeWatcher watcher,
+    ILogger<BlogHotReloadService> logger) : BackgroundService
+{
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        logger.LogInformation("BlogHotReloadService is starting.");
+
+        await rendererService.RenderAsync();
+
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            logger.LogDebug("Watching file changes...");
+            string? changFile = await watcher.WaitForChange(stoppingToken);
+
+            if (changFile is null)
+            {
+                logger.LogInformation("BlogHotReloadService is stopping.");
+                break;
+            }
+
+            logger.LogInformation("{} changed, re-rendering.", changFile);
+            essayContentService.Clear();
+            await rendererService.RenderAsync();
+        }
+    }
+}

YaeBlog.Core/Services/EssayContentService.cs

@@ -11,12 +11,18 @@ public class EssayContentService : IEssayContentService
 
     private readonly Dictionary<EssayTag, List<BlogEssay>> _tags = [];
 
+    private readonly ConcurrentDictionary<string, BlogHeadline> _headlines = new();
+
     public bool TryAdd(BlogEssay essay) => _essays.TryAdd(essay.FileName, essay);
 
+    public bool TryAddHeadline(string filename, BlogHeadline headline) => _headlines.TryAdd(filename, headline);
+
     public IReadOnlyDictionary<string, BlogEssay> Essays => _essays;
 
     public IReadOnlyDictionary<EssayTag, List<BlogEssay>> Tags => _tags;
 
+    public IReadOnlyDictionary<string, BlogHeadline> Headlines => _headlines;
+
     public void RefreshTags()
     {
          _tags.Clear();
@@ -45,4 +51,11 @@ public class EssayContentService : IEssayContentService
 
         return result is not null;
     }
+
+    public void Clear()
+    {
+        _essays.Clear();
+        _tags.Clear();
+        _headlines.Clear();
+    }
 }

YaeBlog.Core/Services/RendererService.cs

@@ -14,7 +14,7 @@ public partial class RendererService(
     ILogger<RendererService> logger,
     IEssayScanService essayScanService,
     MarkdownPipeline markdownPipeline,
-    EssayContentService essayContentService)
+    IEssayContentService essayContentService)
 {
     private readonly Stopwatch _stopwatch = new();
 

YaeBlog.Core/Services/TableOfContentService.cs

@@ -1,20 +0,0 @@
-using System.Collections.Concurrent;
-using YaeBlog.Core.Abstractions;
-using YaeBlog.Core.Models;
-
-namespace YaeBlog.Core.Services;
-
-public class TableOfContentService : ITableOfContentService
-{
-    private readonly ConcurrentDictionary<string, BlogHeadline> _headlines = [];
-
-    public IReadOnlyDictionary<string, BlogHeadline> Headlines => _headlines;
-
-    public void AddHeadline(string filename, BlogHeadline headline)
-    {
-        if (!_headlines.TryAdd(filename, headline))
-        {
-            throw new InvalidOperationException();
-        }
-    }
-}

YaeBlog.Core/YaeBlog.Core.csproj

@@ -6,10 +6,6 @@
     <ImplicitUsings>enable</ImplicitUsings>
   </PropertyGroup>
 
-  <ItemGroup>
-    <SupportedPlatform Include="browser" />
-  </ItemGroup>
-
   <ItemGroup>
     <FrameworkReference Include="Microsoft.AspNetCore.App" />
   </ItemGroup>

YaeBlog/Commands/CommandExtensions.cs

@@ -23,6 +23,38 @@ public static class CommandExtensions
             builder.Services.AddControllers();
             builder.Services.AddBlazorBootstrap();
             builder.AddYaeBlog();
+            builder.AddServer();
+
+            WebApplication application = builder.Build();
+
+            application.UseStaticFiles();
+            application.UseAntiforgery();
+            application.UseYaeBlog();
+
+            application.MapRazorComponents<App>()
+                .AddInteractiveServerRenderMode();
+            application.MapControllers();
+
+            CancellationToken token = context.GetCancellationToken();
+            await application.RunAsync(token);
+        });
+    }
+
+    public static void AddWatchCommand(this RootCommand rootCommand)
+    {
+        Command command = new("watch", "Start a blog watcher that re-render when file changes.");
+        rootCommand.AddCommand(command);
+
+        command.SetHandler(async context =>
+        {
+            WebApplicationBuilder builder = WebApplication.CreateBuilder();
+
+            builder.Services.AddRazorComponents()
+                .AddInteractiveServerComponents();
+            builder.Services.AddControllers();
+            builder.Services.AddBlazorBootstrap();
+            builder.AddYaeBlog();
+            builder.AddWatcher();
 
             WebApplication application = builder.Build();
 

YaeBlog/Pages/Essays.razor

@@ -4,7 +4,6 @@
 @using YaeBlog.Core.Models
 
 @inject IEssayContentService Contents
-@inject ITableOfContentService TableOfContent
 @inject NavigationManager NavigationInstance
 
 <PageTitle>
@@ -129,7 +128,7 @@
             NavigationInstance.NavigateTo("/NotFound");
         }
 
-        _headline = TableOfContent.Headlines[BlogKey];
+        _headline = Contents.Headlines[BlogKey];
     }
 
     private string GenerateSelectorUrl(string selectorId)

YaeBlog/Program.cs

@@ -6,5 +6,6 @@ RootCommand rootCommand = new("YaeBlog CLI");
 rootCommand.AddServeCommand();
 rootCommand.AddNewCommand();
 rootCommand.AddListCommand();
+rootCommand.AddWatchCommand();
 
 await rootCommand.InvokeAsync(args);