Is Handlebars.Net case sensitive again?

There are a few places that mention that Handlebars.Net is supposed to be case insensitive as of v1.6.6 but I can't seem to get it to act that way.

Am I doing something wrong in the code? Below is a basic example of what I'm doing

var templateString = "Dear {{displayName}}";
var template = Handlebars.Compile(templateString);

var data = new ExpandoObject();
data.TryAdd("DisplayName", "John");

var output = template(data);

Console.WriteLine(output);

This just results in Dear .
If I change templateString to be "Dear {{DisplayName}}" it would print Dear John

This is using the NuGet package v1.10.1 on a .NET Core 3.1 console application.

[oformaniuk]

Hello @brandon-vs . Unfortunately not everything can be handled in case-insensitive way. For example consider data object implementing IDictionary<string, object> (applies to your example with ExpandoObject) - in order to get value from the object members of IDictionary<string, object> will be used. If data source provide case-insensitive access to properties (e.g. new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase)) you'd get case-insensitive behavior. The same is true for POCOs as the library performs case-insensitive property search.
Unfortunately the library is not able to handle cases when IDictionary<string, object> data source does not provide case-insensitive behavior as it would require wrapping such object with some kind of proxy that would handle case-insensitive search. Including such functionality as a default behavior can impact performance.

However starting from 2.0 you would be able to handle such problems on you own by registering custom IObjectDescriptorProvider:

[Fact]
public void CaseInsensitiveExpandoObject()
{
    var templateString = "Dear {{displayName}}";
    var configuration = new HandlebarsConfiguration();
    configuration.CompileTimeConfiguration.ObjectDescriptorProviders.Add(new ExpandoObjectDescriptor());
    var handlebars = Handlebars.Create(configuration);
    var template = handlebars.Compile(templateString);

    var data = new ExpandoObject();
    data.TryAdd("DisplayName", "John");

    var output = template(data);

    Assert.Equal("Dear John", output);
}

public class ExpandoObjectDescriptor : IObjectDescriptorProvider
{
    public bool CanHandleType(Type type)
    {
        return typeof(ExpandoObject).IsAssignableFrom(type);
    }

    public bool TryGetDescriptor(Type type, out ObjectDescriptor value)
    {
        if (!typeof(ExpandoObject).IsAssignableFrom(type))
        {
            value = ObjectDescriptor.Empty;;
            return false;
        }
        
        value = new ObjectDescriptor(
            type, 
            new ExpandoObjectMemberAccessor(), 
            (descriptor, o) => ((IDynamicMetaObjectProvider)o).GetMetaObject(Expression.Constant(o)).GetDynamicMemberNames()
            );

        return true;
    }
    
    private class ExpandoObjectMemberAccessor : IMemberAccessor
    {
        public bool TryGetValue(object instance, Type instanceType, string memberName, out object value)
        {
            if (instance is ExpandoObject expandoObject)
            {
                var invariant = memberName.ToUpperInvariant();
                var property = ((IDynamicMetaObjectProvider) expandoObject)
                    .GetMetaObject(Expression.Constant(expandoObject))
                    .GetDynamicMemberNames()
                    .FirstOrDefault(o => o.ToUpperInvariant() == invariant);

                if (property != null)
                {
                    value = ((IDictionary<string, object>) expandoObject)[property];
                    return true;
                }
            }

            value = null;
            return false;
        }
    }
}

Be aware that proposed API is not final and may change prior to v2 release.

@zjklee Thank you very much for the quick response and detailed explanation. Now that I understand the behavior a bit more I was able to fix my code.