jwt/jwt.go

68 lines
1.4 KiB
Go

package jwt
import (
"strings"
"errors"
"encoding/base64"
"encoding/json"
"time"
)
// A JWT Token
type Token struct {
Header map[string]interface{}
Claims map[string]interface{}
Method SigningMethod
Signature string
Valid bool
}
func Parse(tokenString string, keyFunc func(*Token)(string, error)) (token *Token, err error) {
parts := strings.Split(tokenString, ".")
if len(parts) == 3 {
token = new(Token)
// parse Header
var headerBytes []byte
if headerBytes, err = base64.URLEncoding.DecodeString(parts[0]); err != nil {
return
}
if err = json.Unmarshal(headerBytes, &token.Header); err != nil {
return
}
// parse Claims
var claimBytes []byte
if claimBytes, err = base64.URLEncoding.DecodeString(parts[0]); err != nil {
return
}
if err = json.Unmarshal(claimBytes, &token.Claims); err != nil {
return
}
// Lookup signature method
if method, ok := token.Header["alg"].(string); ok {
if token.Method, err = GetSigningMethod(method); err != nil {
return
}
} else {
err = errors.New("Signing method (alg) is unspecified.")
return
}
// Check expiry times
if exp, ok := token.Claims["exp"].(float64); ok {
if time.Now().Unix() > int64(exp) {
err = errors.New("Token is expired")
}
}
// Lookup key
} else {
err = errors.New("Token contains an invalid number of segments")
}
return
}