golang jwt验证

• 安装
  go get “github.com/dgrijalva/jwt-go”

• 登陆

// Create a new token object, specifying signing method and the claims
// you would like it to contain.
token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
    "foo": "bar",
    "nbf": time.Date(2015, 10, 10, 12, 0, 0, 0, time.UTC).Unix(),
})

// Sign and get the complete encoded token as a string using the secret
tokenString, err := token.SignedString(hmacSampleSecret)

fmt.Println(tokenString, err)

• 验证
  在调用Parse时，会进行加密验证，同时如果提供了exp，会进行过期验证；
  如果提供了iat，会进行发行时间验证;如果提供了nbf，会进行发行时间验证．

hmacSampleSecret := []byte("my_secret_key")

// sample token string taken from the New example
tokenString := "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJuYmYiOjE0NDQ0Nzg0MDB9.u1riaD1rW97opCoAuRCTy4w58Br-Zk-bh7vLiRIsrpU"

// Parse takes the token string and a function for looking up the key. The latter is especially
// useful if you use multiple keys for your application.  The standard is to use 'kid' in the
// head of the token to identify which key to use, but the parsed token (head and claims) is provided
// to the callback, providing flexibility.
token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
    // Don't forget to validate the alg is what you expect:
    if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
        return nil, fmt.Errorf("Unexpected signing method: %v", token.Header["alg"])
    }

    // hmacSampleSecret is a []byte containing your secret, e.g. []byte("my_secret_key")
    return hmacSampleSecret, nil
})

if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
    fmt.Println(claims["foo"], claims["nbf"])
} else {
    fmt.Println(err)
}