Allow easy subclassing default IJsonMapper implementations: to let adjust settings easily.

[RufusJWB]

Is it possible to tell the default JSON serializer to ignore empty fields of a JWK and don't serialize them?

Currently my JWS header looks like this after serialization:

{
  "alg": "ES256",
  "JWK": {
    "kty": "EC",
    "use": null,
    "alg": null,
    "keyId": null,
    "keyOps": null,
    "k": null,
    "n": null,
    "e": null,
    "d": null,
    "p": null,
    "dp": null,
    "q": null,
    "dq": null,
    "qi": null,
    "crv": null,
    "x": "mS9EPo_7ZJGgva3NJMAMFBrYj_a65y7wNc6dXLVgAho",
    "y": "3JB6m2MWaMvcIJVqV2WSH59SLtPsa2MtGrCRTsgPPo8",
    "x5U": null,
    "x5T": null,
    "x5TSha256": null,
    "x5C": [
      "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"
    ],
    "otherParams": null
  }
}

And I'd like to have it look like this:

{
  "alg": "ES256",
  "JWK": {
    "kty": "EC",
    "x": "mS9EPo_7ZJGgva3NJMAMFBrYj_a65y7wNc6dXLVgAho",
    "y": "3JB6m2MWaMvcIJVqV2WSH59SLtPsa2MtGrCRTsgPPo8",
    "x5C": [
      "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"
    ]
  }
}

[dvsekhvalnov]

Hi @RufusJWB , can you please share code that producing it?

And also environment details, .net version, core or framework, OS, json serializer (newtonsoft vs. system.text.json), e.t.c.

I haven't seen it in my setup, may be env specific issue or json serializer specific.

[RufusJWB]

Hi @dvsekhvalnov !

Thank you for your support!

Please find following the sources, that generate this output:

using Jose;
using NLog;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;

NLog.LogManager.Setup().LoadConfiguration(builder =>
{
    builder.ForLogger().FilterMinLevel(LogLevel.Trace).WriteToConsole();
});

NLog.Logger Logger = NLog.LogManager.GetCurrentClassLogger();

var payload = new Dictionary<string, object>()
{
    { "termsOfServiceAgreed", true },
    { "contact", new []{ "mailto:rufus.buschart@siemens.com"} }
};


X509Certificate2 selfSignedIDevID = new X509Certificate2("C:\\Users\\z002m76a\\Desktop\\certificate.pem");

var publicKey = selfSignedIDevID.GetECDsaPublicKey();

Jwk jwk = new Jwk(publicKey,isPrivate:false);
jwk.Add(selfSignedIDevID);

var extraHeaders = new Dictionary<string, object>()
{
    {"nonce","6S8IqOGY7eL2lsGoTZYifg" },
    {"url","https://acme-v02.api.letsencrypt.org/acme/new-acct"},
    {"JWK",jwk }
};

var eccPrivPem = File.ReadAllText("C:\\Users\\z002m76a\\Desktop\\private_key.pem");
var privateKey = ECDsa.Create();
privateKey.ImportFromPem(eccPrivPem);

var mapper = Jose.JWT.DefaultSettings.JsonMapper;

Logger.Debug("Mapper: {@typof}", mapper.GetType());

string token = Jose.JWT.Encode(payload:payload, key: privateKey, algorithm:JwsAlgorithm.ES256, extraHeaders:extraHeaders);

Logger.Debug("Token: {@token}",token);

I'm using Visual Studio Professional 2022, Version 17.5.0 Preview 2.0. The application is a console application targeting .net 7.

[dvsekhvalnov]

@RufusJWB , try:

{"JWK", jwk.ToDictionary() } // instead of just 'jwk'

[RufusJWB]

@RufusJWB , try:

{"JWK", jwk.ToDictionary() } // instead of just 'jwk'

I can confirm, that this works. But it seems to be a rather ugly work-around. I would like to propose, to expose the serializer options of the serializer, as there is no global way of setting them: dotnet/runtime#31094 (comment)

[dvsekhvalnov]

Your question - is exactly why library is trying to avoid serialization/deserialization of objects at all :)

Because there is no guarantee that you will use System.Text.Json. It can be Newtonsoft or something else, and then suddenly library have to deal with all those options: skip nulls, avoid defaults, e.t.c. multiplied by number of json parser implementation.

Trying to stick to bare minimum which more or less working same across everything: primites, maps and lists :)

[RufusJWB]

I totally understand that, but it would help a lot, if you would make the Serializer / Deserializer property publicly available: https://github.com/dvsekhvalnov/jose-jwt/blob/master/jose-jwt/json/JsonMapper.cs#L13

[dvsekhvalnov]

But you can always register your own JsonMapper with any settings you like: https://github.com/dvsekhvalnov/jose-jwt#settings

isn't it what you looking for if you want to adjust default behavior?

i can make SerializeOptions/DeserializeOptions protected for instance, will be easier to inherit default impl?

[RufusJWB]

i can make SerializeOptions/DeserializeOptions protected for instance, will be easier to inherit default impl?

That's something I'd appreciate as I want to avoid implementing my own JsonMapper just for changing some basic setting. You know, programmers are lazy people :-)

[dvsekhvalnov]

Okay, should be easy. How badly you want it @RufusJWB ? Like right now or can wait?

[RufusJWB]

Okay, should be easy. How badly you want it @RufusJWB ? Like right now or can wait?

It can wait. It's just about code aesthetics. The proposed work around works fine.

[dvsekhvalnov]

Okay, you can also just submit PR for this any time, can speed up things :)