Inline css (#200)

* Fix tests.

* Temp

* CSS Inline. Close #111

* Fix tests

* Small refactoring.

* Fix build.

Directory.Build.props

@@ -12,6 +12,6 @@
     <RepositoryUrl>https://github.com/SebastianStehle/mjml-net.git</RepositoryUrl>
     <RepositoryType>git</RepositoryType>
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>
-    <Version>3.14.0</Version>
+    <Version>3.15.0</Version>
   </PropertyGroup>
 </Project>

Html.Net.PostProcessors/Html.Net.PostProcessors.csproj

@@ -0,0 +1,47 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>net6.0;net7.0;net8.0</TargetFrameworks>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <NeutralLanguage>en</NeutralLanguage>
+	<LangVersion>latest</LangVersion>
+	<RootNamespace>Mjml.Net</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="AngleSharp" Version="1.1.2" />
+    <PackageReference Include="AngleSharp.Css" Version="1.0.0-beta.139" />
+    <PackageReference Include="Meziantou.Analyzer" Version="2.0.145">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+    <PackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+    <PackageReference Include="RefactoringEssentials" Version="5.6.0" PrivateAssets="all" />
+    <PackageReference Include="StyleCop.Analyzers" Version="1.2.0-beta.507" PrivateAssets="all" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <AdditionalFiles Include="..\stylecop.json" Link="stylecop.json" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Include="..\README.md">
+      <Pack>True</Pack>
+      <PackagePath></PackagePath>
+    </None>
+
+    <None Include="icon.png">
+      <Pack>True</Pack>
+      <PackagePath></PackagePath>
+    </None>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Mjml.Net\Mjml.Net.csproj" />
+  </ItemGroup>
+
+</Project>

Html.Net.PostProcessors/InlineCssPostProcessor.cs

@@ -0,0 +1,105 @@
+using AngleSharp;
+using AngleSharp.Css;
+using AngleSharp.Dom;
+using Mjml.Net;
+
+namespace Html.Net;
+
+public sealed class InlineCssPostProcessor : IPostProcessor
+{
+    private const string FallbackStyle = "non_inline_style";
+    private static readonly IConfiguration HtmlConfiguration =
+        Configuration.Default
+            .WithCss()
+            .Without<ICssDefaultStyleSheetProvider>();
+
+    public static readonly InlineCssPostProcessor Instance = new InlineCssPostProcessor();
+
+    private InlineCssPostProcessor()
+    {
+    }
+
+    public async ValueTask<string> PostProcessAsync(string html, MjmlOptions options,
+        CancellationToken ct)
+    {
+        var context = BrowsingContext.New(HtmlConfiguration);
+
+        var document = await context.OpenAsync(req => req.Content(html), ct);
+
+        Traverse(document, a => RenameNonInline(a, document));
+        Traverse(document, InlineStyle);
+        Traverse(document, a => RestoreNonInline(a, document));
+
+        var result = document.ToHtml();
+
+        return result;
+    }
+
+    private static void Traverse(INode node, Action<IElement> action)
+    {
+        foreach (var child in node.ChildNodes.ToList())
+        {
+            Traverse(child, action);
+        }
+
+        if (node is IElement element)
+        {
+            action(element);
+        }
+    }
+
+    private static void InlineStyle(IElement element)
+    {
+        var currentStyle = element.ComputeCurrentStyle();
+
+        if (currentStyle.Any())
+        {
+            var css = currentStyle.ToCss();
+
+            element.SetAttribute(TagNames.Style, css);
+        }
+    }
+
+    private static void RenameNonInline(IElement element, IDocument document)
+    {
+        if (string.Equals(element.TagName, TagNames.Style, StringComparison.OrdinalIgnoreCase) && !IsInline(element))
+        {
+            RenameTag(element, FallbackStyle, document);
+        }
+    }
+
+    private static void RestoreNonInline(IElement element, IDocument document)
+    {
+        if (string.Equals(element.TagName, FallbackStyle, StringComparison.OrdinalIgnoreCase))
+        {
+            RenameTag(element, TagNames.Style, document);
+        }
+
+        if (string.Equals(element.TagName, TagNames.Style, StringComparison.OrdinalIgnoreCase) && IsInline(element))
+        {
+            element.Remove();
+        }
+    }
+
+    private static bool IsInline(IElement element)
+    {
+        return element.HasAttribute("inline");
+    }
+
+    private static void RenameTag(IElement node, string tagName, IDocument document)
+    {
+        var clone = document.CreateElement(tagName);
+
+        foreach (var attribute in node.Attributes)
+        {
+            clone.SetAttribute(attribute.NamespaceUri, attribute.Name, attribute.Value);
+        }
+
+        var parent = node.Parent!;
+
+        clone.InnerHtml = node.InnerHtml;
+
+        parent.InsertBefore(clone, node);
+        parent.RemoveChild(node);
+    }
+}

Mjml.Net.Benchmark/TemplateBenchmarks.cs

@@ -10,7 +10,6 @@ namespace Mjml.Net.Benchmarking;
 public class TemplateBenchmarks
 {
     private static readonly MjmlOptions WithBeautify = new MjmlOptions { Beautify = true };
-    private static readonly MjmlOptions WithMinify = new MjmlOptions { Minify = true };
     private readonly MjmlRenderer MjmlRenderer;
 
     [ParamsSource(nameof(MjmlTemplates))]
@@ -61,10 +60,4 @@ public string Render_Template_Beautify()
     {
         return MjmlRenderer.Render(MjmlTemplate, WithBeautify).Html;
     }
-
-    [Benchmark]
-    public string Render_Template_Minify()
-    {
-        return MjmlRenderer.Render(MjmlTemplate, WithMinify).Html;
-    }
 }

Mjml.Net.sln

@@ -13,6 +13,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Tools", "Tools\Tools.csproj
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Mjml.Net.Benchmark", "Mjml.Net.Benchmark\Mjml.Net.Benchmark.csproj", "{3969326A-B528-4120-8E30-4127F66B638E}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Html.Net.PostProcessors", "Html.Net.PostProcessors\Html.Net.PostProcessors.csproj", "{BADECB72-90D2-44F3-AA93-27B0247C8FA9}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -39,6 +41,10 @@ Global
 		{3969326A-B528-4120-8E30-4127F66B638E}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{3969326A-B528-4120-8E30-4127F66B638E}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{3969326A-B528-4120-8E30-4127F66B638E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{BADECB72-90D2-44F3-AA93-27B0247C8FA9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{BADECB72-90D2-44F3-AA93-27B0247C8FA9}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{BADECB72-90D2-44F3-AA93-27B0247C8FA9}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{BADECB72-90D2-44F3-AA93-27B0247C8FA9}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

Mjml.Net/AttributeTypes.cs

@@ -18,6 +18,8 @@ public static class AttributeTypes
 
     public static readonly IType IncludeType = new EnumType(true, "mjml", "html", "css");
 
+    public static readonly IType Inline = new EnumType(true, "inline");
+
     public static readonly IType Pixels = new NumberType(Unit.Pixels);
 
     public static readonly IType PixelsOrAuto = new OneOfType(new EnumType(false, "auto"), Pixels);

Mjml.Net/BindType.cs

@@ -10,6 +10,7 @@ public enum BindType
     File,
     FourPixelsOrPercent,
     LeftRight,
+    Inline,
     Pixels,
     PixelsOrAuto,
     PixelsOrEm,

Mjml.Net/Components/Head/StyleComponent.cs

@@ -8,7 +8,7 @@ public partial class StyleComponent : HeadComponentBase
 
     public override string ComponentName => "mj-style";
 
-    [Bind("inline")]
+    [Bind("inline", BindType.Inline)]
     public string? Inline;
 
     [BindText]
@@ -19,7 +19,9 @@ public override void Render(IHtmlRenderer renderer, GlobalContext context)
         // Just in case that validation is disabled.
         if (Text != null)
         {
-            var style = Style.Static(Text);
+            var isInline = string.Equals(Inline, "inline", StringComparison.OrdinalIgnoreCase);
+
+            var style = Style.Static(Text, isInline);
 
             // Allow multiple styles.
             context.AddGlobalData(style);

Mjml.Net/Components/IncludeComponent.cs

@@ -14,6 +14,9 @@ public sealed partial class IncludeComponent : Component
     [Bind("path", BindType.RequiredString)]
     public string Path;
 
+    [Bind("css-inline", BindType.Inline)]
+    public string? CssInline;
+
     [Bind("type", typeof(TypeValidator))]
     public string Type;
 
@@ -153,8 +156,10 @@ public override void Render(IHtmlRenderer renderer, GlobalContext context)
         }
         else if (ActualType == IncludeType.Css)
         {
+            var isInline = string.Equals(CssInline, "inline", StringComparison.OrdinalIgnoreCase);
+
             // Allow multiple styles and render them later.
-            context.AddGlobalData(Style.Static(new InnerTextOrHtml(content)));
+            context.AddGlobalData(Style.Static(new InnerTextOrHtml(content), isInline));
         }
     }
 

Mjml.Net/Helpers/Style.cs

@@ -2,11 +2,11 @@
 
 namespace Mjml.Net.Helpers;
 
-public sealed record Style(Action<IHtmlRenderer, GlobalContext> Renderer) : GlobalData
+public sealed record Style(Action<IHtmlRenderer, GlobalContext> Renderer, bool Inline = false) : GlobalData
 {
-    public static Style Static(InnerTextOrHtml text)
+    public static Style Static(InnerTextOrHtml text, bool inline)
     {
-        return new Style((renderer, _) => renderer.Content(text));
+        return new Style((renderer, _) => renderer.Content(text), inline);
     }
 }
 
@@ -65,11 +65,23 @@ private static void WriteMediaQueriesThunderbird(IHtmlRenderer renderer, GlobalC
     }
 
     private static void WriteStyles(IHtmlRenderer renderer, GlobalContext context)
+    {
+        WriteStyles(renderer, context, context.GlobalData.Values.OfType<Style>().Where(x => !x.Inline), null);
+
+        var inlineStyles = context.GlobalData.Values.OfType<Style>().Where(x => x.Inline).ToList();
+        if (inlineStyles.Count > 0)
+        {
+            WriteStyles(renderer, context, inlineStyles, "inline");
+        }
+    }
+
+    private static void WriteStyles(IHtmlRenderer renderer, GlobalContext context, IEnumerable<Style> inline, string? inlineAttr)
     {
         renderer.StartElement("style")
+            .Attr("inline", inlineAttr)
             .Attr("type", "text/css");
 
-        foreach (var style in context.GlobalData.Values.OfType<Style>())
+        foreach (var style in inline)
         {
             style.Renderer(renderer, context);
         }

Mjml.Net/IMjmlRenderer.cs

@@ -92,7 +92,7 @@ public interface IMjmlRenderer
     /// The result of rendering, including the HTML and validation errors.
     /// </returns>
     /// <remarks>
-    /// This method is thread safe.
+    /// This method is thread safe. Post processors are not run in the sync method.
     /// </remarks>
     RenderResult Render(Stream mjml, MjmlOptions? options = null);
 
@@ -105,7 +105,52 @@ public interface IMjmlRenderer
     /// The result of rendering, including the HTML and validation errors.
     /// </returns>
     /// <remarks>
-    /// This method is thread safe.
+    /// This method is thread safe. Post processors are not run in the sync method.
     /// </remarks>
     RenderResult Render(TextReader mjml, MjmlOptions? options = null);
+
+    /// <summary>
+    /// Renders MJML from a string.
+    /// </summary>
+    /// <param name="mjml">The MJML as string.</param>
+    /// <param name="options">Optional options.</param>
+    /// <param name="ct">The cancellation token.</param>
+    /// <returns>
+    /// The result of rendering, including the HTML and validation errors.
+    /// </returns>
+    /// <remarks>
+    /// This method is thread safe. Post processors are not run in the sync method.
+    /// </remarks>
+    ValueTask<RenderResult> RenderAsync(string mjml, MjmlOptions? options = null,
+        CancellationToken ct = default);
+
+    /// <summary>
+    /// Renders MJML from a stream.
+    /// </summary>
+    /// <param name="mjml">The MJML as stream.</param>
+    /// <param name="options">Optional options.</param>
+    /// <param name="ct">The cancellation token.</param>
+    /// <returns>
+    /// The result of rendering, including the HTML and validation errors.
+    /// </returns>
+    /// <remarks>
+    /// This method is thread safe.
+    /// </remarks>
+    ValueTask<RenderResult> RenderAsync(Stream mjml, MjmlOptions? options = null,
+        CancellationToken ct = default);
+
+    /// <summary>
+    /// Renders MJML from a text renderer.
+    /// </summary>
+    /// <param name="mjml">The MJML as text renderer.</param>
+    /// <param name="options">Optional options.</param>
+    /// <param name="ct">The cancellation token.</param>
+    /// <returns>
+    /// The result of rendering, including the HTML and validation errors.
+    /// </returns>
+    /// <remarks>
+    /// This method is thread safe.
+    /// </remarks>
+    ValueTask<RenderResult> RenderAsync(TextReader mjml, MjmlOptions? options = null,
+        CancellationToken ct = default);
 }

Mjml.Net/IPostProcessor.cs

@@ -0,0 +1,7 @@
+namespace Mjml.Net;
+
+public interface IPostProcessor
+{
+    ValueTask<string> PostProcessAsync(string html, MjmlOptions options,
+        CancellationToken ct);
+}

Mjml.Net/Internal/HtmlReaderWrapper.cs

@@ -1,5 +1,4 @@
 using HtmlPerformanceKit;
-using System;
 using HtmlReaderImpl = HtmlPerformanceKit.HtmlReader;
 
 namespace Mjml.Net.Internal;