Migrating from V1 to V2

[servlette]

Hi,
I have a raw JWK key which I used to parse in v1 but failing on v2

V1:

package main
import (
	"context"
	"fmt"
	"github.com/lestrrat-go/jwx/jwk"
)

func main() {

	//Got this from https://mkjwk.org/
	sampleJWK := `{
		  "kty" : "RSA",
		  "kid" : "cc34c0a0-bd5a-4a3c-a50d-a2a7db7643df",
		  "use" : "sig",
		  "n"   : "pjdss8ZaDfEH6K6U7GeW2nxDqR4IP049fk1fK0lndimbMMVBdPv_hSpm8T8EtBDxrUdi1OHZfMhUixGaut-3nQ4GG9nM249oxhCtxqqNvEXrmQRGqczyLxuh-fKn9Fg--hS9UpazHpfVAFnB5aCfXoNhPuI8oByyFKMKaOVgHNqP5NBEqabiLftZD3W_lsFCPGuzr4Vp0YS7zS2hDYScC2oOMu4rGU1LcMZf39p3153Cq7bS2Xh6Y-vw5pwzFYZdjQxDn8x8BG3fJ6j8TGLXQsbKH1218_HcUJRvMwdpbUQG5nvA2GXVqLqdwp054Lzk9_B_f1lVrmOKuHjTNHq48w",
		  "e"   : "AQAB",
		  "d"   : "ksDmucdMJXkFGZxiomNHnroOZxe8AmDLDGO1vhs-POa5PZM7mtUPonxwjVmthmpbZzla-kg55OFfO7YcXhg-Hm2OWTKwm73_rLh3JavaHjvBqsVKuorX3V3RYkSro6HyYIzFJ1Ek7sLxbjDRcDOj4ievSX0oN9l-JZhaDYlPlci5uJsoqro_YrE0PRRWVhtGynd-_aWgQv1YzkfZuMD-hJtDi1Im2humOWxA4eZrFs9eG-whXcOvaSwO4sSGbS99ecQZHM2TcdXeAs1PvjVgQ_dKnZlGN3lTWoWfQP55Z7Tgt8Nf1q4ZAKd-NlMe-7iqCFfsnFwXjSiaOa2CRGZn-Q",
		  "p"   : "4A5nU4ahEww7B65yuzmGeCUUi8ikWzv1C81pSyUKvKzu8CX41hp9J6oRaLGesKImYiuVQK47FhZ--wwfpRwHvSxtNU9qXb8ewo-BvadyO1eVrIk4tNV543QlSe7pQAoJGkxCia5rfznAE3InKF4JvIlchyqs0RQ8wx7lULqwnn0",
		  "q"   : "ven83GM6SfrmO-TBHbjTk6JhP_3CMsIvmSdo4KrbQNvp4vHO3w1_0zJ3URkmkYGhz2tgPlfd7v1l2I6QkIh4Bumdj6FyFZEBpxjE4MpfdNVcNINvVj87cLyTRmIcaGxmfylY7QErP8GFA-k4UoH_eQmGKGK44TRzYj5hZYGWIC8",
		  "dp"  : "lmmU_AG5SGxBhJqb8wxfNXDPJjf__i92BgJT2Vp4pskBbr5PGoyV0HbfUQVMnw977RONEurkR6O6gxZUeCclGt4kQlGZ-m0_XSWx13v9t9DIbheAtgVJ2mQyVDvK4m7aRYlEceFh0PsX8vYDS5o1txgPwb3oXkPTtrmbAGMUBpE",
		  "dq"  : "mxRTU3QDyR2EnCv0Nl0TCF90oliJGAHR9HJmBe__EjuCBbwHfcT8OG3hWOv8vpzokQPRl5cQt3NckzX3fs6xlJN4Ai2Hh2zduKFVQ2p-AF2p6Yfahscjtq-GY9cB85NxLy2IXCC0PF--Sq9LOrTE9QV988SJy_yUrAjcZ5MmECk",
		  "qi"  : "ldHXIrEmMZVaNwGzDF9WG8sHj2mOZmQpw9yrjLK9hAsmsNr5LTyqWAqJIYZSwPTYWhY4nu2O0EY9G9uYiqewXfCKw_UngrJt8Xwfq1Zruz0YY869zPN4GiE9-9rzdZB33RBw8kIOquY3MK74FMwCihYx_LiU2YTHkaoJ3ncvtvg"
		}`

	set, err := jwk.ParseString(sampleJWK)

	if err != nil {
		panic("Unable to parse JWK!")
	}
	for it := set.Iterate(context.Background()); it.Next(context.Background()); {
		pair := it.Pair()		
		key := pair.Value.(jwk.Key)
               //Prints raw key and works in V1
		fmt.Println(key)
	}

}

The same code when migrated to v2 panics on casting:

V2:

package main

import (
	"context"
	"fmt"
	"github.com/lestrrat-go/jwx/v2/jwk"
)

func main() {

	//Got this from https://mkjwk.org/
	sampleJWK := `{
		  "kty" : "RSA",
		  "kid" : "cc34c0a0-bd5a-4a3c-a50d-a2a7db7643df",
		  "use" : "sig",
		  "n"   : "pjdss8ZaDfEH6K6U7GeW2nxDqR4IP049fk1fK0lndimbMMVBdPv_hSpm8T8EtBDxrUdi1OHZfMhUixGaut-3nQ4GG9nM249oxhCtxqqNvEXrmQRGqczyLxuh-fKn9Fg--hS9UpazHpfVAFnB5aCfXoNhPuI8oByyFKMKaOVgHNqP5NBEqabiLftZD3W_lsFCPGuzr4Vp0YS7zS2hDYScC2oOMu4rGU1LcMZf39p3153Cq7bS2Xh6Y-vw5pwzFYZdjQxDn8x8BG3fJ6j8TGLXQsbKH1218_HcUJRvMwdpbUQG5nvA2GXVqLqdwp054Lzk9_B_f1lVrmOKuHjTNHq48w",
		  "e"   : "AQAB",
		  "d"   : "ksDmucdMJXkFGZxiomNHnroOZxe8AmDLDGO1vhs-POa5PZM7mtUPonxwjVmthmpbZzla-kg55OFfO7YcXhg-Hm2OWTKwm73_rLh3JavaHjvBqsVKuorX3V3RYkSro6HyYIzFJ1Ek7sLxbjDRcDOj4ievSX0oN9l-JZhaDYlPlci5uJsoqro_YrE0PRRWVhtGynd-_aWgQv1YzkfZuMD-hJtDi1Im2humOWxA4eZrFs9eG-whXcOvaSwO4sSGbS99ecQZHM2TcdXeAs1PvjVgQ_dKnZlGN3lTWoWfQP55Z7Tgt8Nf1q4ZAKd-NlMe-7iqCFfsnFwXjSiaOa2CRGZn-Q",
		  "p"   : "4A5nU4ahEww7B65yuzmGeCUUi8ikWzv1C81pSyUKvKzu8CX41hp9J6oRaLGesKImYiuVQK47FhZ--wwfpRwHvSxtNU9qXb8ewo-BvadyO1eVrIk4tNV543QlSe7pQAoJGkxCia5rfznAE3InKF4JvIlchyqs0RQ8wx7lULqwnn0",
		  "q"   : "ven83GM6SfrmO-TBHbjTk6JhP_3CMsIvmSdo4KrbQNvp4vHO3w1_0zJ3URkmkYGhz2tgPlfd7v1l2I6QkIh4Bumdj6FyFZEBpxjE4MpfdNVcNINvVj87cLyTRmIcaGxmfylY7QErP8GFA-k4UoH_eQmGKGK44TRzYj5hZYGWIC8",
		  "dp"  : "lmmU_AG5SGxBhJqb8wxfNXDPJjf__i92BgJT2Vp4pskBbr5PGoyV0HbfUQVMnw977RONEurkR6O6gxZUeCclGt4kQlGZ-m0_XSWx13v9t9DIbheAtgVJ2mQyVDvK4m7aRYlEceFh0PsX8vYDS5o1txgPwb3oXkPTtrmbAGMUBpE",
		  "dq"  : "mxRTU3QDyR2EnCv0Nl0TCF90oliJGAHR9HJmBe__EjuCBbwHfcT8OG3hWOv8vpzokQPRl5cQt3NckzX3fs6xlJN4Ai2Hh2zduKFVQ2p-AF2p6Yfahscjtq-GY9cB85NxLy2IXCC0PF--Sq9LOrTE9QV988SJy_yUrAjcZ5MmECk",
		  "qi"  : "ldHXIrEmMZVaNwGzDF9WG8sHj2mOZmQpw9yrjLK9hAsmsNr5LTyqWAqJIYZSwPTYWhY4nu2O0EY9G9uYiqewXfCKw_UngrJt8Xwfq1Zruz0YY869zPN4GiE9-9rzdZB33RBw8kIOquY3MK74FMwCihYx_LiU2YTHkaoJ3ncvtvg"
		}`

	set, err := jwk.ParseString(sampleJWK)

	if err != nil {
		panic("Unable to parse JWK!")
	}
	for it := set.Iterate(context.Background()); it.Next(context.Background()); {
		pair := it.Pair()
		//The following line panics in V2 as the underlying type is string and not jwk.Key
		//Worked in V1
		key := pair.Value.(jwk.Key)
		fmt.Println(key)
	}

}

On this page I see func ExampleJWK_Usage() { where it has the same approach to parse. Wondering why it did not work for me after migrating to v2.

[servlette]

Versions of v1 and v2 I used:

	github.com/lestrrat-go/jwx v1.2.25
	github.com/lestrrat-go/jwx/v2 v2.0.5

[lestrrat]

Oh weird! Reproduced, and looking into it...

[lestrrat]

Oh, I get it. It's a fine print in the Changes, but (jwk.Set).Iterate() has been changed to (jwk.Set).Keys(). So it's not a bug.
https://github.com/lestrrat-go/jwx/blame/ec808117157fbef32cb62e933a4705baecf37dad/Changes-v2.md#L185

Long answer to follow

[lestrrat]

Previously in v1, jwk.Set was a glorified slice of jwk.Key.
However, we found in the wild usecases where a JWKS contains custom fields, so jwk.Set is now a full-fledged object that can store arbitrary field names. This doesn't bode well when (jwk.Set).Iterate didn't actually iterate through all the arbitrary keys, but the most common use case is to iterate through the keys... so the decision was made to repurpose Iterate() to "iterate all fields in the set", and introduce Keys() to "iterate through all (jwk.Key)s"

So please change your loop to the following (just replace Iterate with Keys) and all should be fine

  for it := set.Keys(context.Background()); it.Next(context.Background()); {
    pair := it.Pair()
    key := pair.Value.(jwk.Key)
    fmt.Println(key)
  }

[servlette]

Thanks, it worked :)