JwtBuilder WithAlgorithmFactory and Encode doesn't work.

[drusellers]

I just tried to use

var builder = JwtBuilder.Create()
    .WithAlgorithmFactory(_myHardCodedFactory)
    .AddHeader("kid", "the-kid")
    .AddClaim("bob", "bill")
    .Encode();

And I got the exception

System.ArgumentNullException : Value cannot be null. (Parameter 'algorithm')
   at JWT.Algorithms.DelegateAlgorithmFactory..ctor(IJwtAlgorithm algorithm)
   at JWT.JwtEncoder..ctor(IJwtAlgorithm algorithm, IJsonSerializer jsonSerializer, IBase64UrlEncoder urlEncoder)
   at JWT.Builder.JwtBuilder.TryCreateEncoder()
   at JWT.Builder.JwtBuilder.EnsureCanEncode()
   at JWT.Builder.JwtBuilder.Encode()
...

Which surprised me because I gave the builder an algorithm factory to use, that will produce an algo if asked.

I also noticed that there aren't any tests that cover using the WithAlgorithmFactory and not providing an WithAlgorithm

Does it make sense to allow this to work for encoding?

Library 9.1

[abatishchev]

Looking at the code:

jwt/src/JWT/Algorithms/DelegateAlgorithmFactory.cs

Lines 23 to 29 in 070389b

	public DelegateAlgorithmFactory(IJwtAlgorithm algorithm)
	{
	if (algorithm is null)
	throw new ArgumentNullException(nameof(algorithm));
	_algFactory = () => algorithm;
	}

The only reason for the error is that _myHardCodedFactory returns null.

Can you make sure it doesn't? Post its code here, if possible. Let's take a look.

[drusellers]

using JWT;
using JWT.Algorithms;
using JWT.Builder;
using NUnit.Framework;


public class JwtBuilderTest
{
    [Test]
    public void Fails()
    {
        var token = JwtBuilder.Create()
            .AddClaim("A","B")
            .WithSecret(new[]{"deadbeef"})
            .WithAlgorithmFactory(new HardCodedFactory())
            .Encode();
    }
    
    [Test]
    public void Passes()
    {
        var token = JwtBuilder.Create()
            .AddClaim("A","B")
            .WithSecret(new[]{"deadbeef"})
            .WithAlgorithm(new HMACSHA256Algorithm())
            .Encode();
    }


    class HardCodedFactory : IAlgorithmFactory
    {
        public IJwtAlgorithm Create(JwtDecoderContext context)
        {
            return new HMACSHA256Algorithm();
        }
    }
}

[abatishchev]

Sorry for the bug and thanks for reporting it. Fixed and published to NuGet as 10.0.0-beta2

[drusellers]

@abatishchev not a problem at all. It's a team effort. TY for being so responsive.