OSOE-837: Support localized HTML strings in Lombiq.VueJs

Lombiq.VueJs.Samples/Assets/Scripts/VueComponents/demo-sfc.vue

@@ -18,6 +18,31 @@
         <!-- Here you can see a non-standard expression. The "[[ ... ]]" is unique to this OC
              module: it performs localization via IStringLocalizer at runtime. -->
         <demo-repeater :data="repeaterData">[[ Hello! ]]</demo-repeater>
+
+        <!-- You can use different converters inside the "[[ ... ]]" to achieve different results. For example the
+             the "[[{ ... }]]" expression runs the contents through IHtmlLocalizer, and treats it like encoded HTML. -->
+        <p>[[{ Does HTML localization escape HTML? <span class="not-html" hidden>YES!</span> <span class="encoded-html">NO!</span> }]]</p>
+
+        <!-- Besides that special case, you can use custom services that implement IVueTemplateConverter. For example
+             here we use the built-in Liquid converter via the "[[{liquid} ... ]]" format. Note that both here and the
+             special case for HTML, you must not have a space between the "[[" and the "{" characters. This ensures,
+             that older well-formatted strings won't be affected.
+             Note that these expressions are substituted server-side, so including "{{ ... }}" from Liquid won't cause
+             problems. -->
+        [[{liquid}
+        <div class="{{ "A Liquid Example" | html_class }}">
+            <h2>{{ "Liquid example! (localized)" | t }}</h2>
+            The current time is: {{ "now" | utc | date: "%c" }}
+        </div> ]]
+
+        <!-- Example of the other built-in converter, for Markdown. -->
+        [[{markdown}
+## Markdown Example
+
+Here is some _Markdown_ content. For more info, see [the docs](https://docs.orchardcore.net/en/main/docs/reference/modules/Markdown/).
+        ]]
+
+        <!-- By the way HTML comments are also stripped out both to save on bandwidth and for security. -->
     </div>
 </template>
 

Lombiq.VueJs.Tests.UI/Extensions/TestCaseUITestContextExtensions.cs

@@ -51,6 +51,15 @@ public static async Task TestVueSfcASync(this UITestContext context)
 
         // Verify localizer HTML escaping.
         context.Missing(By.ClassName("not-html"));
+        context.Exists(By.ClassName("encoded-html"));
+
+        // Verify Liquid and Markdown working.
+        context.Get(By.CssSelector(".a-liquid-example h2")).Text.ShouldContain("Liquid example! (localized)");
+        context.Get(By.Id("markdown-example")).Text.ShouldContain("Markdown Example");
+        context
+            .Get(By.LinkText("the docs"))
+            .GetAttribute("href")
+            .ShouldBe("https://docs.orchardcore.net/en/main/docs/reference/modules/Markdown/");
     }
 
     public static async Task TestVueSfcEnhancedListAsync(this UITestContext context)

Lombiq.VueJs/Services/IVueTemplateExpressionConverter.cs

@@ -0,0 +1,22 @@
+using OrchardCore.DisplayManagement.Implementation;
+using System.Threading.Tasks;
+
+namespace Lombiq.VueJs.Services;
+
+/// <summary>
+/// A service that handles <c>[[{name} input ]]</c> expressions in Vue SFC templates. Used by <see
+/// cref="VueSingleFileComponentShapeTemplateViewEngine"/>.
+/// </summary>
+public interface IVueTemplateExpressionConverter
+{
+    /// <summary>
+    /// Returns a value indicating whether this converter should handle the provided <paramref name="input"/>, typically
+    /// based on the <paramref name="name"/>.
+    /// </summary>
+    bool IsApplicable(string name, string input, DisplayContext displayContext);
+
+    /// <summary>
+    /// Returns the output that should be substituted instead of the provided expression.
+    /// </summary>
+    ValueTask<string> ConvertAsync(string name, string input, DisplayContext displayContext);
+}

Lombiq.VueJs/Services/LiquidVueTemplateExpressionConverter.cs

@@ -0,0 +1,24 @@
+using Fluid;
+using OrchardCore.DisplayManagement.Implementation;
+using OrchardCore.Liquid;
+using System;
+using System.Threading.Tasks;
+
+namespace Lombiq.VueJs.Services;
+
+public class LiquidVueTemplateExpressionConverter : IVueTemplateExpressionConverter
+{
+    private readonly ILiquidTemplateManager _liquidTemplateManager;
+
+    public LiquidVueTemplateExpressionConverter(ILiquidTemplateManager liquidTemplateManager) =>
+        _liquidTemplateManager = liquidTemplateManager;
+
+    public bool IsApplicable(string name, string input, DisplayContext displayContext) =>
+        "liquid".EqualsOrdinalIgnoreCase(name);
+
+    public async ValueTask<string> ConvertAsync(string name, string input, DisplayContext displayContext) =>
+        await _liquidTemplateManager.RenderStringAsync(
+            input,
+            NullEncoder.Default,
+            displayContext);
+}

Lombiq.VueJs/Services/MarkdownVueTemplateExpressionConverter.cs

@@ -0,0 +1,20 @@
+using OrchardCore.DisplayManagement.Implementation;
+using OrchardCore.Markdown.Services;
+using System;
+using System.Threading.Tasks;
+
+namespace Lombiq.VueJs.Services;
+
+public class MarkdownVueTemplateExpressionConverter : IVueTemplateExpressionConverter
+{
+    private readonly IMarkdownService _markdownService;
+
+    public MarkdownVueTemplateExpressionConverter(IMarkdownService markdownService) =>
+        _markdownService = markdownService;
+
+    public bool IsApplicable(string name, string input, DisplayContext displayContext) =>
+        "markdown".EqualsOrdinalIgnoreCase(name);
+
+    public ValueTask<string> ConvertAsync(string name, string input, DisplayContext displayContext) =>
+        ValueTask.FromResult(_markdownService.ToHtml(input));
+}

Lombiq.VueJs/Services/VueSingleFileComponentShapeTemplateViewEngine.cs

@@ -1,14 +1,16 @@
-using Lombiq.HelpfulLibraries.Common.Utilities;
 using Microsoft.AspNetCore.Html;
+using Microsoft.AspNetCore.Mvc.Localization;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.Localization;
+using Microsoft.Extensions.Logging;
 using OrchardCore.DisplayManagement.Descriptors.ShapeTemplateStrategy;
 using OrchardCore.DisplayManagement.Implementation;
 using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Net;
+using System.Text;
 using System.Threading.Tasks;
 
 namespace Lombiq.VueJs.Services;
@@ -20,54 +22,128 @@ public class VueSingleFileComponentShapeTemplateViewEngine : IShapeTemplateViewE
     private readonly IShapeTemplateFileProviderAccessor _fileProviderAccessor;
     private readonly IMemoryCache _memoryCache;
     private readonly IStringLocalizerFactory _stringLocalizerFactory;
+    private readonly IHtmlLocalizerFactory _htmlLocalizerFactory;
+    private readonly ILogger<VueSingleFileComponentShapeTemplateViewEngine> _logger;
     private readonly IEnumerable<IVueSingleFileComponentShapeAmender> _amenders;
+    private readonly IEnumerable<IVueTemplateExpressionConverter> _converters;
 
     public IEnumerable<string> TemplateFileExtensions { get; } = new[] { ".vue" };
 
     public VueSingleFileComponentShapeTemplateViewEngine(
         IShapeTemplateFileProviderAccessor fileProviderAccessor,
         IMemoryCache memoryCache,
         IStringLocalizerFactory stringLocalizerFactory,
-        IEnumerable<IVueSingleFileComponentShapeAmender> amenders)
+        IHtmlLocalizerFactory htmlLocalizerFactory,
+        ILogger<VueSingleFileComponentShapeTemplateViewEngine> logger,
+        IEnumerable<IVueSingleFileComponentShapeAmender> amenders,
+        IEnumerable<IVueTemplateExpressionConverter> converters)
     {
         _fileProviderAccessor = fileProviderAccessor;
         _memoryCache = memoryCache;
         _stringLocalizerFactory = stringLocalizerFactory;
+        _htmlLocalizerFactory = htmlLocalizerFactory;
+        _logger = logger;
         _amenders = amenders;
+        _converters = converters;
     }
 
     public async Task<IHtmlContent> RenderAsync(string relativePath, DisplayContext displayContext)
     {
         var template = await GetTemplateAsync(relativePath);
 
-        var localizationRanges = template
-            .AllIndexesOf("[[")
-            .Where(index => template[(index + 2)..].Contains("]]"))
-            .Select(index => new Range(
-                index,
-                template.IndexOfOrdinal(value: "]]", startIndex: index + 2) + 2))
-            .WithoutOverlappingRanges(isSortedByStart: true);
+        // Remove all HTML comments. This is done first, because HTML comments take precedence over everything else.
+        // This way the contents of comments are guaranteed to not be evaluated.
+        template = template
+            .GetParenthesisRanges("<!--", "-->")
+            .InvertRanges(template.Length)
+            .Join(template);
 
         var shapeName = displayContext.Value.Metadata.Type;
-        var stringLocalizer = _stringLocalizerFactory.Create("Vue.js SFC", shapeName);
+        var builder = new StringBuilder($"<script type=\"x-template\" class=\"{shapeName}\">");
 
-        foreach (var range in localizationRanges.OrderByDescending(range => range.End.Value))
+        var localizationRanges = template.GetParenthesisRanges("[[", "]]");
+        if (localizationRanges.Count > 0)
         {
-            var (before, expression, after) = template.Partition(range);
-            var text = expression[2..^2].Trim();
-            template = before + WebUtility.HtmlEncode(stringLocalizer[text]) + after;
+            await LocalizeRangesAsync(builder, template, localizationRanges, displayContext);
+        }
+        else
+        {
+            builder.Append(template);
         }
 
-        template = StringHelper.CreateInvariant($"<script type=\"x-template\" class=\"{shapeName}\">{template}</script>");
+        builder.Append("</script>");
 
         var entries = new List<object>();
         foreach (var amender in _amenders) entries.AddRange(await amender.PrependAsync(shapeName));
-        entries.Add(new HtmlString(template));
+        entries.Add(new HtmlString(builder.ToString()));
         foreach (var amender in _amenders) entries.AddRange(await amender.AppendAsync(shapeName));
 
         return new HtmlContentBuilder(entries);
     }
 
+    private async Task LocalizeRangesAsync(
+        StringBuilder builder,
+        string template,
+        IList<Range> localizationRanges,
+        DisplayContext context)
+    {
+        var shapeName = context.Value.Metadata.Type;
+        var stringLocalizerLazy = new Lazy<IStringLocalizer>(() => _stringLocalizerFactory.Create("Vue.js SFC", shapeName));
+        var htmlLocalizerLazy = new Lazy<IHtmlLocalizer>(() => _htmlLocalizerFactory.Create("Vue.js SFC HTML", shapeName));
+
+        var startIndex = new Index(0);
+        foreach (var range in localizationRanges)
+        {
+            // Insert content before this range.
+            builder.Append(template[startIndex..range.Start]);
+            startIndex = range.End;
+
+            var expression = template[range];
+            string html;
+
+            // Include a logger warning if the inner spacing is missing. This will cause failures e.g. during UI tests,
+            // and so ensure correct formatting.
+            if (expression[2] is not '{' and not ' ')
+            {
+                _logger.LogWarning(
+                    "Vue SFC localization strings should follow the following formats: [[ text ]], [[{{ html }}]] or " +
+                    "[[{{converter}} input ]]. Please include the inner spacing to ensure future compatibility. Your " +
+                    "expression was: \"{Expression}\".",
+                    expression);
+            }
+
+            // Handle HTML localization.
+            if (expression[2] == '{' && expression[^3] == '}')
+            {
+                var value = expression[3..^3].Trim();
+                html = htmlLocalizerLazy.Value[value].Html();
+            }
+            else if (expression[2] == '{')
+            {
+                var (name, _, input) = expression[3..^2].Partition("}");
+                name = name.Trim();
+                input = input.Trim();
+
+                if (_converters.FirstOrDefault(converter => converter.IsApplicable(name, input, context)) is not { } converter)
+                {
+                    throw new InvalidOperationException($"Unknown converter type \"{name}\".");
+                }
+
+                html = await converter.ConvertAsync(name, input, context) ?? string.Empty;
+            }
+            else
+            {
+                var value = expression[2..^2].Trim();
+                html = WebUtility.HtmlEncode(stringLocalizerLazy.Value[value]);
+            }
+
+            builder.Append(html);
+        }
+
+        // Insert leftover content after the last range.
+        builder.Append(template[localizationRanges[^1].End..]);
+    }
+
     private async Task<string> GetTemplateAsync(string relativePath)
     {
         var cacheName = CachePrefix + relativePath;

Lombiq.VueJs/Startup.cs

@@ -27,5 +27,8 @@ public override void ConfigureServices(IServiceCollection services)
 
         services.AddTransient<IConfigureOptions<ResourceManagementOptions>, ResourceManagementOptionsConfiguration>();
         services.AddAsyncResultFilter<ScriptModuleResourceFilter>();
+
+        services.AddScoped<IVueTemplateExpressionConverter, LiquidVueTemplateExpressionConverter>();
+        services.AddScoped<IVueTemplateExpressionConverter, MarkdownVueTemplateExpressionConverter>();
     }
 }

Readme.md

@@ -82,7 +82,15 @@ Here we excluded `vue` and packages starting with `vuetify` (e.g. `vuetify/compo
 
 ## Using Vue.js Single File Components
 
-The module identifies Single File Components in the _Assets/Scripts/VueComponents_ directory and harvests them as shapes. They have a custom _.vue_ file renderer that displays the content of the `<template>` element after applying localization for the custom `[[ ... ]]` expression that calls `IStringLocalizer`. Besides that, it's pure Vue, yet you can still make use of shape overriding if needed.
+The module identifies Single File Components in the _Assets/Scripts/VueComponents_ directory and harvests them as shapes. They have a custom _.vue_ file renderer that displays the content of the `<template>` element after applying server-side substitution. Besides that, it's pure Vue, yet you can still make use of shape overriding if needed.
+
+The following types of server-side substitution are available:
+
+- `[[ ... ]]`: Uses `IStringLocalizer` and encodes the result so it's safe to use in HTML.
+- `[[{ ... }]]`: Uses `IHtmlLocalizer` and results in raw HTML just like the `@T["..."]` in cshtml views. You can use this for localizing HTML that may contain formatting or structure.
+- `[[{converter_name} input ]]`: Finds an `IVueTemplateExpressionConverter` implementation to generate the replacement text. This module contains two implementations by default, but you can create your own as well.
+  - `[[{liquid} some Liquid expression ]]`: Uses [Liquid](https://docs.orchardcore.net/en/main/docs/reference/modules/Liquid/), including of the filters registered by Orchard Core.
+  - `[[{markdown} some Markdown expression ]]`: Uses [Markdown](https://docs.orchardcore.net/en/main/docs/reference/modules/Markdown/).
 
 See a demo video of using Vue.js Single File Components [here](https://www.youtube.com/watch?v=L0qjpQ6THZU).