EXPERIMENTAL: Add Handlebars Support (#32)

Prototyping and exploration of what Handlebars would look likein.

Handlebars.Net as the supported engine
Handlebar content can be rendered using files with `.hbs` extension in VSCode extension.
Enables nested JSON types in the attributes to support more complex attributes

src/Sage.Engine.Tests/CompilerTests.cs

@@ -45,7 +45,10 @@ public void TestAssemblyGeneration(string sourceFile)
         }
 
         [Test]
+        [TestCase("%%=ADD(1,2)=%%", ContentType.Handlebars, "%%=ADD(1,2)=%%")]
         [TestCase("%%=ADD(1,2)=%%", ContentType.AMPscript, "3")]
+        [TestCase("{{#if true}}Hello{{/if}}", ContentType.AMPscript, "")]
+        [TestCase("{{#if true}}Hello{{/if}}", ContentType.Handlebars, "Hello")]
         public void TestRenderer(string input, ContentType type, string expected)
         {
             var content = new EmbeddedContent(input, "TEST", "TEST", 1, type);

src/Sage.Engine.Tests/Corpus/Handlebars/eachHelper.subscribercontext.json

@@ -0,0 +1,10 @@
+{
+  "people": [
+    {
+      "name": "Adam"
+    },
+    {
+      "name": "Howard"
+    }
+  ]
+}

src/Sage.Engine.Tests/Corpus/Handlebars/eachHelper.txt

@@ -0,0 +1,6 @@
+===========
+eachHelper
+===========
+{{#each people}}<h1>{{name}}</h1>{{/each}}
+++++++++++
+<h1>Adam</h1><h1>Howard</h1>

src/Sage.Engine.Tests/Corpus/Handlebars/ifHelper.subscribercontext.json

@@ -0,0 +1,4 @@
+{
+  "isActiveFalse": false,
+  "isActiveTrue": true
+}

src/Sage.Engine.Tests/Corpus/Handlebars/ifHelper.txt

@@ -0,0 +1,12 @@
+===========
+If True Block
+===========
+{{#if isActiveTrue}}hello{{else}}world{{/if}}
+++++++++++
+hello
+===========
+If False Block
+===========
+{{#if isActiveFalse}}hello{{else}}world{{/if}}
+++++++++++
+world

src/Sage.Engine.Tests/Corpus/Handlebars/stringEncoding.subscribercontext.json

@@ -0,0 +1,4 @@
+{
+  "titleTags": "First Template <p> Tags",
+  "titleNoTags": "First Template No Tags"
+}

src/Sage.Engine.Tests/Corpus/Handlebars/stringEncoding.txt

@@ -0,0 +1,12 @@
+===========
+Escaping
+===========
+{{titleTags}}
+++++++++++
+First Template <p> Tags
+===========
+No Escaping
+===========
+{{titleNoTags}}
+++++++++++
+First Template No Tags

src/Sage.Engine.Tests/Corpus/Handlebars/unlessHelper.subscribercontext.json

@@ -0,0 +1,4 @@
+{
+  "isActiveTrue": true,
+  "isActiveFalse": false
+}

src/Sage.Engine.Tests/Corpus/Handlebars/unlessHelper.txt

@@ -0,0 +1,11 @@
+===========
+Unless Helper False
+===========
+{{#unless isActiveFalse}}hello{{/unless}}
+++++++++++
+hello
+===========
+Unless Helper True
+===========
+{{#unless isActiveTrue}}hello{{/unless}}
+++++++++++

src/Sage.Engine.Tests/Corpus/Handlebars/withHelper.subscribercontext.json

@@ -0,0 +1,6 @@
+{
+  "primary": {
+    "name": "Adam"
+  },
+  "name": "Howard"
+}

src/Sage.Engine.Tests/Corpus/Handlebars/withHelper.txt

@@ -0,0 +1,6 @@
+===========
+WithHelper Tests
+===========
+{{#with primary}}{{name}}{{/with}}
+++++++++++
+Adam

src/Sage.Engine.Tests/HandlebarTests.cs

@@ -0,0 +1,32 @@
+// Copyright (c) 2022, salesforce.com, inc.
+// All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+// For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/Apache-2.0
+
+namespace Sage.Engine.Tests
+{
+    using NUnit.Framework;
+
+    /// <summary>
+    /// Basic tests for the language features and runtime
+    /// </summary>
+    public class HandlebarTests : SageTest
+    {
+        [Test]
+        [RuntimeTest("Handlebars")]
+        public EngineTestResult TestHandlebars(CorpusData test)
+        {
+            try
+            {
+                var result = TestUtils.GetOutputFromHandlebarTest(_serviceProvider, test);
+                Assert.That(result.Output, Is.EqualTo(test.Output));
+                return result;
+            }
+            catch (CompileCodeException e)
+            {
+                Assert.Fail(e.Message);
+                return new EngineTestResult("!");
+            }
+        }
+    }
+}

src/Sage.Engine.Tests/Sage.Engine.Tests.csproj

@@ -83,6 +83,36 @@
     <None Update="Corpus\Function\utility.txt">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <None Update="Corpus\Handlebars\unlessHelper.subscribercontext.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Update="Corpus\Handlebars\stringEncoding.subscribercontext.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Update="Corpus\Handlebars\ifHelper.subscribercontext.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Update="Corpus\Handlebars\eachHelper.subscribercontext.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Update="Corpus\Handlebars\eachHelper.txt">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Update="Corpus\Handlebars\stringEncoding.txt">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Update="Corpus\Handlebars\unlessHelper.txt">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Update="Corpus\Handlebars\withHelper.subscribercontext.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Update="Corpus\Handlebars\withHelper.txt">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Update="Corpus\Handlebars\ifHelper.txt">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
     <None Update="Corpus\Language\attributes.subscribercontext.json">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>

src/Sage.Engine.Tests/TestUtils.cs

@@ -1,12 +1,11 @@
-// Copyright (c) 2022, salesforce.com, inc.
+// Copyright (c) 2022, salesforce.com, inc.
 // All rights reserved.
 // SPDX-License-Identifier: Apache-2.0
 // For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/Apache-2.0
 
 using Antlr4.Runtime.Tree;
 using Microsoft.Extensions.DependencyInjection;
 using Sage.Engine.Compiler;
-using Sage.Engine.Data;
 using Sage.Engine.Parser;
 using Sage.Engine.Runtime;
 
@@ -42,6 +41,27 @@ private static RuntimeContext GetTestRuntimeContext(IServiceProvider serviceProv
     }
 
 
+    /// <summary>
+    /// Uses Handlebars to compile the content instead of the AMPscript compiler
+    /// </summary>
+    public static EngineTestResult GetOutputFromHandlebarTest(IServiceProvider serviceProvider, CorpusData test)
+    {
+        CompilationOptions options = new CompilerOptionsBuilder()
+            .WithContent(new EmbeddedContent(test.Code, test.FileFriendlyName, test.FileFriendlyName, 1, ContentType.Handlebars))
+            .Build();
+
+        try
+        {
+            string result = serviceProvider.GetService<ICompiler>()
+                !.Compile(options, GetTestRuntimeContext(serviceProvider, options, test), test.SubscriberContext);
+            return new EngineTestResult(result.ReplaceLineEndings("\n").Trim());
+        }
+        catch (Exception)
+        {
+            return new EngineTestResult("!");
+        }
+    }
+
     /// <summary>
     /// Executes the engine and gets the expected result from the engine
     /// </summary>
@@ -71,4 +91,4 @@ public static EngineTestResult GetOutputFromTest(IServiceProvider serviceProvide
             return new EngineTestResult("!");
         }
     }
-}
+}

src/Sage.Engine/Content/ContentExtensions.cs

@@ -46,6 +46,13 @@ public static void AddLocalDiskContentClient(this IServiceCollection services, A
         /// </summary>
         public static ContentType InferContentTypeFromFilename(string path)
         {
+            string extension = Path.GetExtension(path).ToLowerInvariant();
+
+            if (extension == ".hbs")
+            {
+                return ContentType.Handlebars;
+            }
+
             return ContentType.AMPscript;
         }
     }

src/Sage.Engine/Content/IContent.cs

@@ -10,7 +10,8 @@ namespace Sage.Engine.Compiler
     /// </summary>
     public enum ContentType
     {
-        AMPscript
+        AMPscript,
+        Handlebars
     };
 
     /// <summary>

src/Sage.Engine/Content/LocalDiskContentClient.cs

@@ -61,6 +61,12 @@ public LocalDiskContentClient(
                 return new LocalFileContent(id, filePath, 1, ContentType.AMPscript);
             }
 
+            filePath = Path.Combine(_options.InputDirectory.FullName, $"{id}.hbs");
+            if (File.Exists(filePath))
+            {
+                return new LocalFileContent(id, filePath, 1, ContentType.Handlebars);
+            }
+
             return null;
         }
     }

src/Sage.Engine/DependencyInjection/SageDependencyInjectionExtensions.cs

@@ -10,6 +10,7 @@
 using Sage.Engine.Data.DependencyInjection;
 using Sage.Engine.Data.Sqlite;
 using Sage.Engine.Extensions;
+using Sage.Engine.Handlebars;
 
 namespace Sage.Engine.DependencyInjection
 {
@@ -61,6 +62,7 @@ public static void AddSage(
             services.AddLocalDiskContentClient();
             services.AddScoped<Renderer>();
             services.AddScoped<ICompiler, AmpscriptCompiler>();
+            services.AddScoped<ICompiler, HandlebarsCompiler>();
         }
     }
 }

src/Sage.Engine/Handlebars/HandlebarsCompiler.cs

@@ -0,0 +1,44 @@
+// Copyright (c) 2023, salesforce.com, inc.
+// All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+// For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/Apache-2.0
+
+using HandlebarsDotNet;
+using HandlebarsDotNet.Extension.Json;
+using Sage.Engine.Compiler;
+using Sage.Engine.Runtime;
+
+namespace Sage.Engine.Handlebars
+{
+    /// <summary>
+    /// Uses HandlebarsDotNet to compile content to a string.
+    ///
+    /// Does not support AMPscript embedded in the content.
+    /// </summary>
+    internal class HandlebarsCompiler : IHandlebarsCompiler
+    {
+        private IHandlebars _handlebar;
+
+        public HandlebarsCompiler()
+        {
+            _handlebar = HandlebarsDotNet.Handlebars.Create();
+            _handlebar.Configuration.UseJson();
+        }
+
+        public bool CanCompile(IContent content)
+        {
+            return content.ContentType == ContentType.Handlebars;
+        }
+
+        public string Compile(CompilationOptions options, RuntimeContext runtimeContext, SubscriberContext? subscriberContext)
+        {
+            var template = _handlebar.Compile(options.Content.GetTextReader());
+
+            StringWriter writer = new StringWriter();
+
+            template(writer, subscriberContext?.GetRichAttributes());
+
+            return writer.ToString();
+        }
+    }
+}

src/Sage.Engine/Handlebars/IHandlebarsCompiler.cs

@@ -0,0 +1,14 @@
+// Copyright (c) 2023, salesforce.com, inc.
+// All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+// For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/Apache-2.0
+
+namespace Sage.Engine.Handlebars
+{
+    /// <summary>
+    /// Renders a piece of Handlebars content to a string.
+    /// </summary>
+    public interface IHandlebarsCompiler : ICompiler
+    {
+    }
+}

src/Sage.Engine/Runtime/RuntimeContext.cs

@@ -49,21 +49,8 @@ public RuntimeContext(
             _contentBuilderContentClient = provider.GetRequiredService<IContentBuilderContentClient>();
             _dataExtensionClient = provider.GetRequiredService<IDataExtensionClient>();
             _dataExtensionClient.ConnectAsync().Wait();
-
-            string subscriberContextFile =
-                Path.Combine(Path.GetDirectoryName(_rootCompilationOptions.Content.Location), "subscriber.json");
-            if (subscriberContext != null)
-            {
-                _subscriberContext = subscriberContext;
-            }
-            else if (Path.Exists(subscriberContextFile))
-            {
-                _subscriberContext = new SubscriberContext(File.ReadAllText(subscriberContextFile));
-            }
-            else
-            {
-                _subscriberContext = new SubscriberContext(null);
-            }
+
+            _subscriberContext = subscriberContext ?? new SubscriberContext(null);
 
             _stackFrame.Push(new StackFrame(_rootCompilationOptions.GeneratedMethodName, _rootCompilationOptions.Content));
         }
@@ -229,14 +216,15 @@ public SubscriberContext GetSubscriberContext()
 
         internal string? CompileAndExecuteReferencedCode(CompilationOptions currentOptions)
         {
-            CompileResult compileResult = CSharpCompiler.GenerateAssemblyFromSource(currentOptions);
 
             string poppedContext;
 
             PushContext(currentOptions.GeneratedMethodName, currentOptions.Content);
 
             try
             {
+
+                CompileResult compileResult = CSharpCompiler.GenerateAssemblyFromSource(currentOptions);
                 compileResult.Execute(this);
             }
             finally