How to handle parse error types

[BigBoulard]

Hi,

I know it probably sounds like a dumb question but I can't find how to get the different error types after parsing.

import (
  "github.com/lestrrat-go/jwx/v2/jwa"
  "github.com/lestrrat-go/jwx/v2/jwt"
)

func (s *service) VerifyAppJWT(appJWS string) (jwt.Token, error) {
  AppJWT, err := jwt.Parse([]byte(appJWS), jwt.WithKey(jwa.ES256, conf.App.PublicJWK))
   
   if err != nil {
        return err // <------ pretty short error handling here :|

        // So, I'm searching something like below:
	// 	if errors.Is(err, jwt.ErrTokenMalformed) {
	// 	}
	// 	if errors.Is(err, jwt.ErrTokenSignatureInvalid) {
	// 	}
	// 	if errors.Is(err, jwt.ErrTokenExpired) || errors.Is(err, jwt.ErrTokenNotValidYet) {
	// 	} else {
	// 	}
	// }
    }
}

Best.

[lestrrat]

(EDIT: This will no longer be true once v3 is out: you will be able to distinguish between oft-used errors using errors.Is)

---

In general this library tries to avoid enumerating error types, so there isn't a complete set of errors like that.
There are some, mainly for JWT validation, but that's probably not up to par with what you are looking for (grep for func Err in jwt directory for these)

(I wrote a long explanation on why that is here, but I'm cutting it b/c it's probably not what you want to hear)

---

I suggest you actually separate this out into smaller steps if you want that kind of micro error management.

payload, err := jws.Verify(jwsPayload, ....);
if err != nil { // this is going to be a JWS error, so you can inform them as much
  ...
}

token, err := jwt.Parse(payload) // no need to verify here, it's already verified
// You could even do var token = jwt.New(); json.Unmarshal(&token, payload)
// if you don't need signature verification
if err != nil { // this is going to be a JWT formatting issue
  ...
}

if err := jwt.Validate(token, ....); err != nil { // there's something wrong in the validity
  // You can use `errors.Is` with one of the predefined error type if you want. See jwt/validate.go and jwt/validate_test.go
  ...
}

[BigBoulard]

Thanks Mate