NativeAOT support

[ivanjx]

hi,

is this library supported in a native aot compiled .net application (i am on version .net 8)? thanks.

[ivanjx]

i tested a simple case with JsonDocument and it seem to work:

using System.Text.Json;
using HandlebarsDotNet;
using HandlebarsDotNet.Extension.Json;

var model = JsonDocument.Parse("{\"Key1\": \"Val1\", \"Key2\": \"Val2\"}");

var source = "{{#each this}}{{@key}}={{@value}}\n{{/each}}";

var handlebars = Handlebars.Create();
handlebars.Configuration.UseJson();

var template = handlebars.Compile(source);

var output = template(model);
Console.WriteLine(output);

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <PropertyGroup Condition="'$(Configuration)'=='Release'">
    <PublishAot>true</PublishAot>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Handlebars.Net" Version="2.1.4" />
    <PackageReference Include="Handlebars.Net.Extension.Json" Version="1.0.0" />
  </ItemGroup>

</Project>

[ivanjx]

sadly i cant make it work with a simple dictionary:

source =
@"<div class=""entry"">
  <h1>{{title}}</h1>
  <div class=""body"">
    {{body}}
  </div>
</div>";

template = Handlebars.Compile(source);

Dictionary<string, string> data = new()
{
    { "title", "my new post" },
    { "body", "this is my post" }
};

var result = template(data);
Console.WriteLine(result);

Unhandled Exception: HandlebarsDotNet.HandlebarsCompilerException: An unhandled exception occurred while trying to compile the template
 ---> HandlebarsDotNet.HandlebarsCompilerException: An unhandled exception occurred while trying to compile the template
 ---> System.ArgumentException: The handle is invalid.
   at System.Reflection.Runtime.General.ReflectionCoreCallbacksImplementation.GetMethodFromHandle(RuntimeMethodHandle, RuntimeTypeHandle) + 0xc7
   at HandlebarsDotNet.Compiler.PathBinder.VisitPathExpression(PathExpression) + 0x9ef
   at HandlebarsDotNet.Compiler.PathBinder.VisitStatementExpression(StatementExpression) + 0x67
   at System.Dynamic.Utils.ExpressionVisitorUtils.VisitBlockExpressions(ExpressionVisitor, BlockExpression) + 0x4e
   at System.Linq.Expressions.ExpressionVisitor.VisitBlock(BlockExpression) + 0x1d
   at HandlebarsDotNet.Compiler.FunctionBuilder.Reduce(Expression, CompilationContext, IReadOnlyList`1&) + 0x1bc
   at HandlebarsDotNet.Compiler.FunctionBuilder.CreateExpression(IEnumerable`1, CompilationContext, IReadOnlyList`1&) + 0xf3
   --- End of inner exception stack trace ---
   at HandlebarsDotNet.Compiler.FunctionBuilder.CreateExpression(IEnumerable`1, CompilationContext, IReadOnlyList`1&) + 0x1e4
   at HandlebarsDotNet.Compiler.FunctionBuilder.Compile(IEnumerable`1, CompilationContext, IReadOnlyList`1&) + 0x14
   --- End of inner exception stack trace ---
   at HandlebarsDotNet.Compiler.FunctionBuilder.Compile(IEnumerable`1, CompilationContext, IReadOnlyList`1&) + 0xd8
   at HandlebarsDotNet.Compiler.HandlebarsCompiler.Compile(ExtendedStringReader, CompilationContext) + 0xd9
   at HandlebarsDotNet.HandlebarsEnvironment.Compile(TextReader) + 0x126
   at HandlebarsDotNet.HandlebarsEnvironment.Compile(String) + 0x62
   at Program.<Main>$(String[] args) + 0xf3
   at naot!<BaseAddress>+0x340110
Aborted (core dumped)

[ivanjx]

also thankfully it works correctly with custom objects with source generator:

using System.Text.Json;
using System.Text.Json.Serialization;
using HandlebarsDotNet;
using HandlebarsDotNet.Extension.Json;

var model = JsonSerializer.SerializeToDocument(
    new[]
    {
        new Model("ivan", "programmer"),
        new Model("jane", "cook"),
        new Model("joe", "athlete")
    },
    MyContext.Default.ModelArray);

var source = "{{#each this}}Name: {{name}}\nJob: {{job}}\n\n{{/each}}";

var handlebars = Handlebars.Create();
handlebars.Configuration.UseJson();

var template = handlebars.Compile(source);

var output = template(model);
Console.WriteLine(output);
Console.WriteLine();

public class Model
{
    [JsonPropertyName("name")]
    public string Name
    {
        get;
        set;
    }

    [JsonPropertyName("job")]
    public string Job
    {
        get;
        set;
    }

    public Model(string name, string job)
    {
        Name = name;
        Job = job;
    }
}

[JsonSerializable(typeof(Model[]))]
public partial class MyContext : JsonSerializerContext
{
}

[ivanjx]

the only problematic part is that i have to do this in the csproj otherwise it will have runtime error on Debug (not release):

  <PropertyGroup Condition="'$(Configuration)'=='Release'">
    <PublishAot>true</PublishAot>
  </PropertyGroup>

the error:

Unhandled exception. HandlebarsDotNet.HandlebarsCompilerException: An unhandled exception occurred while trying to compile the template
 ---> HandlebarsDotNet.HandlebarsCompilerException: An unhandled exception occurred while trying to compile the template
 ---> HandlebarsDotNet.HandlebarsCompilerException: An unhandled exception occurred while trying to compile the template
 ---> System.PlatformNotSupportedException: Dynamic code generation is not supported on this platform.
   at System.Reflection.Emit.AssemblyBuilder.ThrowDynamicCodeNotSupported()
   at System.Reflection.Emit.DynamicMethod.Init(String name, MethodAttributes attributes, CallingConventions callingConvention, Type returnType, Type[] signature, Type owner, Module m, Boolean skipVisibility, Boolean transparentMethod)
   at System.Reflection.Emit.DynamicMethod..ctor(String name, Type returnType, Type[] parameterTypes)
   at System.Dynamic.Utils.DelegateHelpers.CreateObjectArrayDelegateRefEmit(Type delegateType, Func`2 handler)
   at System.Linq.Expressions.Expression`1.Compile()
   at HandlebarsDotNet.Features.DefaultCompilerFeature.DefaultExpressionCompiler.Compile[T](Expression`1 expression)
   at HandlebarsDotNet.Compiler.FunctionBuilder.Compile(IEnumerable`1 expressions, CompilationContext compilationContext, IReadOnlyList`1& decorators)
   --- End of inner exception stack trace ---
   at HandlebarsDotNet.Compiler.FunctionBuilder.Compile(IEnumerable`1 expressions, CompilationContext compilationContext, IReadOnlyList`1& decorators)
   at HandlebarsDotNet.Compiler.IteratorBinder.VisitIteratorExpression(IteratorExpression iex)
   at HandlebarsDotNet.Compiler.HandlebarsExpressionVisitor.Visit(Expression exp)
   at System.Dynamic.Utils.ExpressionVisitorUtils.VisitBlockExpressions(ExpressionVisitor visitor, BlockExpression block)
   at System.Linq.Expressions.ExpressionVisitor.VisitBlock(BlockExpression node)
   at HandlebarsDotNet.Compiler.HandlebarsExpressionVisitor.Visit(Expression exp)
   at HandlebarsDotNet.Compiler.FunctionBuilder.Reduce(Expression expression, CompilationContext context, IReadOnlyList`1& decorators)
   at HandlebarsDotNet.Compiler.FunctionBuilder.CreateExpression(IEnumerable`1 expressions, CompilationContext compilationContext, IReadOnlyList`1& decorators)
   --- End of inner exception stack trace ---
   at HandlebarsDotNet.Compiler.FunctionBuilder.CreateExpression(IEnumerable`1 expressions, CompilationContext compilationContext, IReadOnlyList`1& decorators)
   at HandlebarsDotNet.Compiler.FunctionBuilder.Compile(IEnumerable`1 expressions, CompilationContext compilationContext, IReadOnlyList`1& decorators)
   --- End of inner exception stack trace ---
   at HandlebarsDotNet.Compiler.FunctionBuilder.Compile(IEnumerable`1 expressions, CompilationContext compilationContext, IReadOnlyList`1& decorators)
   at HandlebarsDotNet.Compiler.HandlebarsCompiler.Compile(ExtendedStringReader source, CompilationContext compilationContext)
   at HandlebarsDotNet.HandlebarsEnvironment.Compile(TextReader template)
   at HandlebarsDotNet.HandlebarsEnvironment.Compile(String template)
   at Program.<Main>$(String[] args) in /home/x/naot/naot/Program.cs:line 20

i am not familiar of how the library work but if it is possible to disable dynamic code gen for JsonDocument then i think i wont have to do the csproj thing.