How to extract the claims from JWT token

Question

I'm using the dgrijalva/jwt-go/ package.

I would like to extract the payload from the token, and I couldn't find a way to do it.

---

Example (taken from : https://jwt.io/):

for encoded:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWV9.TJVA95OrM7E2cBab30RMHrHDcEfxjoYZgeFONFh7HgQ

I would like to extract the payload:

{
  "sub": "1234567890",
  "name": "John Doe",
  "admin": true
}

---

I will be grateful for an example (using golang).

Answer 1

Sample Code:

    func extractClaims(tokenStr string) (jwt.MapClaims, bool) {
        hmacSecretString := // Value
        hmacSecret := []byte(hmacSecretString)
        token, err := jwt.Parse(tokenStr, func(token *jwt.Token) (interface{}, error) {
             // check token signing method etc
             return hmacSecret, nil
        })

        if err != nil {
            return nil, false
        }

        if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
            return claims, true
        } else {
            log.Printf("Invalid JWT Token")
            return nil, false
        }
    }