feat: add support for MediaWiki-style templates

OliverBooth/Data/Web/ArticleTemplate.cs

@@ -0,0 +1,82 @@
+using SmartFormat;
+using SmartFormat.Core.Extensions;
+
+namespace OliverBooth.Data.Web;
+
+/// <summary>
+///     Represents a MediaWiki-style template.
+/// </summary>
+public sealed class ArticleTemplate : IEquatable<ArticleTemplate>
+{
+    /// <summary>
+    ///     Gets or sets the format string.
+    /// </summary>
+    /// <value>The format string.</value>
+    public string FormatString { get; set; } = string.Empty;
+
+    /// <summary>
+    ///     Gets the name of the template.
+    /// </summary>
+    public string Name { get; private set; } = string.Empty;
+
+    /// <summary>
+    ///     Returns a value indicating whether two instances of <see cref="ArticleTemplate" /> are equal.
+    /// </summary>
+    /// <param name="left">The first instance of <see cref="ArticleTemplate" /> to compare.</param>
+    /// <param name="right">The second instance of <see cref="ArticleTemplate" /> to compare.</param>
+    /// <returns>
+    ///     <see langword="true" /> if <paramref name="left" /> and <paramref name="right" /> are equal; otherwise,
+    ///     <see langword="false" />.
+    /// </returns>
+    public static bool operator ==(ArticleTemplate? left, ArticleTemplate? right) => Equals(left, right);
+
+    /// <summary>
+    ///     Returns a value indicating whether two instances of <see cref="ArticleTemplate" /> are not equal.
+    /// </summary>
+    /// <param name="left">The first instance of <see cref="ArticleTemplate" /> to compare.</param>
+    /// <param name="right">The second instance of <see cref="ArticleTemplate" /> to compare.</param>
+    /// <returns>
+    ///     <see langword="true" /> if <paramref name="left" /> and <paramref name="right" /> are not equal; otherwise,
+    ///     <see langword="false" />.
+    /// </returns>
+    public static bool operator !=(ArticleTemplate? left, ArticleTemplate? right) => !(left == right);
+
+    /// <summary>
+    ///     Returns a value indicating whether this instance of <see cref="ArticleTemplate" /> is equal to another
+    ///     instance.
+    /// </summary>
+    /// <param name="other">An instance to compare with this instance.</param>
+    /// <returns>
+    ///     <see langword="true" /> if <paramref name="other" /> is equal to this instance; otherwise,
+    ///     <see langword="false" />.
+    /// </returns>
+    public bool Equals(ArticleTemplate? other)
+    {
+        if (ReferenceEquals(null, other)) return false;
+        if (ReferenceEquals(this, other)) return true;
+        return Name == other.Name;
+    }
+
+    /// <summary>
+    ///     Returns a value indicating whether this instance is equal to a specified object.
+    /// </summary>
+    /// <param name="obj">An object to compare with this instance.</param>
+    /// <returns>
+    ///     <see langword="true" /> if <paramref name="obj" /> is an instance of <see cref="ArticleTemplate" /> and
+    ///     equals the value of this instance; otherwise, <see langword="false" />.
+    /// </returns>
+    public override bool Equals(object? obj)
+    {
+        return ReferenceEquals(this, obj) || obj is ArticleTemplate other && Equals(other);
+    }
+
+    /// <summary>
+    ///     Gets the hash code for this instance.
+    /// </summary>
+    /// <returns>The hash code.</returns>
+    public override int GetHashCode()
+    {
+        // ReSharper disable once NonReadonlyMemberInGetHashCode
+        return Name.GetHashCode();
+    }
+}

OliverBooth/Data/Web/Configuration/ArticleTemplateConfiguration.cs

@@ -0,0 +1,19 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+
+namespace OliverBooth.Data.Web.Configuration;
+
+/// <summary>
+///     Represents the configuration for the <see cref="ArticleTemplate" /> entity.
+/// </summary>
+internal sealed class ArticleTemplateConfiguration : IEntityTypeConfiguration<ArticleTemplate>
+{
+    public void Configure(EntityTypeBuilder<ArticleTemplate> builder)
+    {
+        builder.ToTable("ArticleTemplate");
+        builder.HasKey(e => e.Name);
+
+        builder.Property(e => e.Name).IsRequired();
+        builder.Property(e => e.FormatString).IsRequired();
+    }
+}

OliverBooth/Data/WebContext.cs

@@ -1,4 +1,6 @@
 using Microsoft.EntityFrameworkCore;
+using OliverBooth.Data.Web;
+using OliverBooth.Data.Web.Configuration;
 
 namespace OliverBooth.Data;
 
@@ -9,11 +11,21 @@ public sealed class WebContext : DbContext
 {
     private readonly IConfiguration _configuration;
 
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="WebContext" /> class.
+    /// </summary>
+    /// <param name="configuration">The configuration.</param>
     public WebContext(IConfiguration configuration)
     {
         _configuration = configuration;
     }
 
+    /// <summary>
+    ///     Gets the set of article templates.
+    /// </summary>
+    /// <value>The set of article templates.</value>
+    public DbSet<ArticleTemplate> ArticleTemplates { get; private set; } = null!;
+
     /// <inheritdoc />
     protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
     {
@@ -24,5 +36,6 @@ public sealed class WebContext : DbContext
 
     protected override void OnModelCreating(ModelBuilder modelBuilder)
     {
+        modelBuilder.ApplyConfiguration(new ArticleTemplateConfiguration());
     }
 }

OliverBooth/DateFormatter.cs

@@ -0,0 +1,33 @@
+using System.Globalization;
+using SmartFormat.Core.Extensions;
+
+namespace OliverBooth;
+
+/// <summary>
+///     Represents a SmartFormat formatter that formats a date.
+/// </summary>
+internal sealed class DateFormatter : IFormatter
+{
+    /// <inheritdoc />
+    public bool CanAutoDetect { get; set; } = true;
+
+    /// <inheritdoc />
+    public string Name { get; set; } = "date";
+
+    /// <inheritdoc />
+    public bool TryEvaluateFormat(IFormattingInfo formattingInfo)
+    {
+        if (formattingInfo.CurrentValue is not string value)
+            return false;
+
+        if (!DateTime.TryParseExact(value, "yyyy-MM-dd",
+                CultureInfo.InvariantCulture,
+                DateTimeStyles.None,
+                out DateTime date))
+            return false;
+
+
+        formattingInfo.Write(date.ToString(formattingInfo.Format?.ToString()));
+        return true;
+    }
+}

OliverBooth/Markdown/TemplateExtension.cs

@@ -0,0 +1,33 @@
+using Markdig;
+using Markdig.Renderers;
+using OliverBooth.Services;
+
+namespace OliverBooth.Markdown;
+
+/// <summary>
+///     Represents a Markdown extension that adds support for MediaWiki-style templates.
+/// </summary>
+internal sealed class TemplateExtension : IMarkdownExtension
+{
+    private readonly TemplateService _templateService;
+
+    public TemplateExtension(TemplateService templateService)
+    {
+        _templateService = templateService;
+    }
+
+    /// <inheritdoc />
+    public void Setup(MarkdownPipelineBuilder pipeline)
+    {
+        pipeline.InlineParsers.AddIfNotAlready<TemplateInlineParser>();
+    }
+
+    /// <inheritdoc />
+    public void Setup(MarkdownPipeline pipeline, IMarkdownRenderer renderer)
+    {
+        if (renderer is HtmlRenderer htmlRenderer)
+        {
+            htmlRenderer.ObjectRenderers.Add(new TemplateRenderer(_templateService));
+        }
+    }
+}

OliverBooth/Markdown/TemplateInline.cs

@@ -0,0 +1,33 @@
+using Markdig.Syntax.Inlines;
+
+namespace OliverBooth.Markdown;
+
+/// <summary>
+///     Represents a Markdown inline element that represents a MediaWiki-style template.
+/// </summary>
+public sealed class TemplateInline : Inline
+{
+    /// <summary>
+    ///     Gets the raw argument string.
+    /// </summary>
+    /// <value>The raw argument string.</value>
+    public string ArgumentString { get; set; } = string.Empty;
+
+    /// <summary>
+    ///     Gets the argument list.
+    /// </summary>
+    /// <value>The argument list.</value>
+    public IReadOnlyList<string> ArgumentList { get; set; } = ArraySegment<string>.Empty;
+
+    /// <summary>
+    ///     Gets the name of the template.
+    /// </summary>
+    /// <value>The name of the template.</value>
+    public string Name { get; set; } = string.Empty;
+
+    /// <summary>
+    ///     Gets the template parameters.
+    /// </summary>
+    /// <value>The template parameters.</value>
+    public Dictionary<string, string> Params { get; set; } = new();
+}

OliverBooth/Markdown/TemplateInlineParser.cs

@@ -0,0 +1,167 @@
+using Cysharp.Text;
+using Markdig.Helpers;
+using Markdig.Parsers;
+
+namespace OliverBooth.Markdown;
+
+/// <summary>
+///     Represents a Markdown inline parser that handles MediaWiki-style templates.
+/// </summary>
+public sealed class TemplateInlineParser : InlineParser
+{
+    /// <inheritdoc />
+    public override bool Match(InlineProcessor processor, ref StringSlice slice)
+    {
+        ReadOnlySpan<char> span = slice.Text.AsSpan();
+        ReadOnlySpan<char> template = span[slice.Start..];
+
+        if (!template.StartsWith("{{"))
+        {
+            return false;
+        }
+
+        int endIndex = template.IndexOf("}}");
+        if (endIndex == -1)
+        {
+            return false;
+        }
+
+        template = template[2..endIndex];
+        ReadOnlySpan<char> templateName = template;
+        int pipeIndex = template.IndexOf('|');
+        var templateArgs = new Dictionary<string, string>();
+        var rawArgumentString = string.Empty;
+        var argumentList = new List<string>();
+
+        if (pipeIndex != -1)
+        {
+            templateName = templateName[..pipeIndex];
+            rawArgumentString = template[(pipeIndex + 1)..].ToString();
+
+            ReadOnlySpan<char> args = template[(pipeIndex + 1)..];
+
+            using Utf8ValueStringBuilder keyBuilder = ZString.CreateUtf8StringBuilder();
+            using Utf8ValueStringBuilder valueBuilder = ZString.CreateUtf8StringBuilder();
+
+            var isKey = true;
+            var isEscape = false;
+            var nestLevel = 0;
+
+            for (var index = 0; index < args.Length; index++)
+            {
+                char current = args[index];
+                var key = keyBuilder.ToString();
+                var value = valueBuilder.ToString();
+
+                if (current == '=' && isKey && !isEscape)
+                {
+                    isKey = false;
+                    continue;
+                }
+
+                if (current == '{' && index < args.Length - 1 && args[index + 1] == '{')
+                {
+                    nestLevel++;
+                }
+
+                if (current == '}' && index < args.Length - 1 && args[index + 1] == '}')
+                {
+                    if (nestLevel == 0)
+                    {
+                        template = template[..(pipeIndex + 1 + index)];
+                        args = args[..index];
+                    }
+                    else
+                    {
+                        nestLevel--;
+                    }
+                }
+
+                if (isKey)
+                {
+                    if (current == '\'')
+                    {
+                        if (isEscape)
+                        {
+                            keyBuilder.Append('\'');
+                            isEscape = false;
+                            continue;
+                        }
+
+                        isEscape = !isEscape;
+
+                        if (index == args.Length - 1)
+                        {
+                            argumentList.Add(isKey ? key : $"{key}={value}");
+                            templateArgs.Add(key, value);
+                        }
+
+                        continue;
+                    }
+
+                    if (current == '|' && !isEscape)
+                    {
+                        argumentList.Add(key);
+                        templateArgs.Add(key, string.Empty);
+                        keyBuilder.Clear();
+
+                        if (index == args.Length - 1)
+                        {
+                            argumentList.Add(isKey ? key : $"{key}={value}");
+                            templateArgs.Add(key, value);
+                        }
+
+                        continue;
+                    }
+
+                    keyBuilder.Append(current);
+
+                    if (index == args.Length - 1)
+                    {
+                        argumentList.Add(isKey ? key : $"{key}={value}");
+                        templateArgs.Add(key, value);
+                    }
+
+                    continue;
+                }
+
+                if (current == '\'')
+                {
+                    if (isEscape)
+                    {
+                        valueBuilder.Append('\'');
+                        isEscape = false;
+                        continue;
+                    }
+
+                    isEscape = !isEscape;
+                    continue;
+                }
+
+                if (current == '|' && !isEscape)
+                {
+                    argumentList.Add($"{key}={value}");
+                    templateArgs.Add(key, value);
+                    keyBuilder.Clear();
+                    valueBuilder.Clear();
+                    isKey = true;
+                    continue;
+                }
+
+                valueBuilder.Append(current);
+            }
+        }
+
+        processor.Inline = new TemplateInline
+        {
+            Name = templateName.ToString(),
+            Params = templateArgs,
+            ArgumentString = rawArgumentString,
+            ArgumentList = argumentList.ToArray()
+        };
+
+        slice.End = slice.Start;
+        slice.Start += template.Length + 4;
+        return true;
+    }
+}

OliverBooth/Markdown/TemplateRenderer.cs

@@ -0,0 +1,28 @@
+using Markdig.Renderers;
+using Markdig.Renderers.Html;
+using OliverBooth.Services;
+
+namespace OliverBooth.Markdown;
+
+/// <summary>
+///     Represents a Markdown object renderer that handles <see cref="TemplateInline" /> elements.
+/// </summary>
+internal sealed class TemplateRenderer : HtmlObjectRenderer<TemplateInline>
+{
+    private readonly TemplateService _templateService;
+
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="TemplateRenderer" /> class.
+    /// </summary>
+    /// <param name="templateService">The <see cref="TemplateService" />.</param>
+    public TemplateRenderer(TemplateService templateService)
+    {
+        _templateService = templateService;
+    }
+
+    /// <inheritdoc />
+    protected override void Write(HtmlRenderer renderer, TemplateInline template)
+    {
+        renderer.Write(_templateService.RenderTemplate(template));
+    }
+}

OliverBooth/OliverBooth.csproj

@@ -24,6 +24,7 @@
         <PackageReference Include="SmartFormat.NET" Version="3.2.2"/>
         <PackageReference Include="X10D" Version="3.2.2"/>
         <PackageReference Include="X10D.Hosting" Version="3.2.2"/>
+        <PackageReference Include="ZString" Version="2.5.0"/>
     </ItemGroup>
 
 </Project>

OliverBooth/Program.cs

@@ -1,6 +1,7 @@
 using Markdig;
 using NLog.Extensions.Logging;
 using OliverBooth.Data;
+using OliverBooth.Markdown;
 using OliverBooth.Services;
 using X10D.Hosting.DependencyInjection;
 
@@ -10,7 +11,9 @@ builder.Configuration.AddTomlFile("data/config.toml", true, true);
 builder.Logging.ClearProviders();
 builder.Logging.AddNLog();
 builder.Services.AddHostedSingleton<LoggingService>();
-builder.Services.AddSingleton(new MarkdownPipelineBuilder()
+builder.Services.AddSingleton<TemplateService>();
+
+builder.Services.AddSingleton(provider => new MarkdownPipelineBuilder()
     .UseAbbreviations()
     .UseAdvancedExtensions()
     .UseBootstrap()
@@ -23,6 +26,7 @@ builder.Services.AddSingleton(new MarkdownPipelineBuilder()
     .UseMathematics()
     .UseAutoIdentifiers()
     .UseAutoLinks()
+    .Use(new TemplateExtension(provider.GetRequiredService<TemplateService>()))
     .Build());
 
 builder.Services.AddDbContextFactory<BlogContext>();

OliverBooth/Services/BlogService.cs

@@ -43,7 +43,7 @@ public sealed class BlogService
     /// <returns>The processed content of the blog post.</returns>
     public string GetContent(BlogPost post)
     {
-        return ProcessContent(post.Body);
+        return RenderContent(post.Body);
     }
 
     /// <summary>
@@ -61,7 +61,7 @@ public sealed class BlogService
         int moreIndex = span.IndexOf("<!--more-->", StringComparison.Ordinal);
         trimmed = moreIndex != -1 || span.Length > 256;
         string result = moreIndex != -1 ? span[..moreIndex].Trim().ToString() : post.Body.Truncate(256);
-        return ProcessContent(result);
+        return RenderContent(result);
     }
 
     /// <summary>
@@ -139,8 +139,8 @@ public sealed class BlogService
         post = context.BlogPosts.FirstOrDefault(p => p.WordPressId == postId);
         return post is not null;
     }
-
-    private string ProcessContent(string content)
+    
+    private string RenderContent(string content)
     {
         content = content.Replace("<!--more-->", string.Empty);
 
@@ -149,6 +149,6 @@ public sealed class BlogService
             content = content.Replace("\n\n", "\n");
         }
 
-        return Markdown.ToHtml(content.Trim(), _markdownPipeline);
+        return Markdig.Markdown.ToHtml(content.Trim(), _markdownPipeline);
     }
 }

OliverBooth/Services/TemplateService.cs

@@ -0,0 +1,69 @@
+using Microsoft.EntityFrameworkCore;
+using OliverBooth.Data;
+using OliverBooth.Data.Web;
+using OliverBooth.Markdown;
+using SmartFormat;
+using SmartFormat.Extensions;
+
+namespace OliverBooth.Services;
+
+/// <summary>
+///     Represents a service that renders MediaWiki-style templates.
+/// </summary>
+public sealed class TemplateService
+{
+    private readonly IDbContextFactory<WebContext> _webContextFactory;
+    private readonly SmartFormatter _formatter;
+
+    /// <summary>
+    ///     Initializes a new instance of the <see cref="TemplateService" /> class.
+    /// </summary>
+    /// <param name="webContextFactory">The <see cref="WebContext" /> factory.</param>
+    public TemplateService(IDbContextFactory<WebContext> webContextFactory)
+    {
+        _formatter = Smart.CreateDefaultSmartFormat();
+        _formatter.AddExtensions(new DefaultSource());
+        _formatter.AddExtensions(new ReflectionSource());
+        _formatter.AddExtensions(new DateFormatter());
+        
+        _webContextFactory = webContextFactory;
+        Current = this;
+    }
+
+    public static TemplateService Current { get; private set; } = null!;
+
+    /// <summary>
+    ///     Renders the specified template with the specified arguments.
+    /// </summary>
+    /// <param name="templateInline">The template to render.</param>
+    /// <returns>The rendered template.</returns>
+    /// <exception cref="ArgumentNullException">
+    ///     <paramref name="templateInline" /> is <see langword="null" />.
+    /// </exception>
+    public string RenderTemplate(TemplateInline templateInline)
+    {
+        if (templateInline is null) throw new ArgumentNullException(nameof(templateInline));
+        using WebContext webContext = _webContextFactory.CreateDbContext();
+        ArticleTemplate? template = webContext.ArticleTemplates.Find(templateInline.Name);
+        if (template is null)
+        {
+            return $"{{{{{templateInline.Name}}}}}";
+        }
+
+        var formatted = new
+        {
+            templateInline.ArgumentList,
+            templateInline.ArgumentString,
+            templateInline.Params,
+        };
+
+        try
+        {
+            return Markdig.Markdown.ToHtml(_formatter.Format(template.FormatString, formatted));
+        }
+        catch
+        {
+            return $"{{{{{templateInline.Name}|{templateInline.ArgumentString}}}}}";
+        }
+    }
+}