added utc time functions

jwt.go

@@ -135,7 +135,7 @@ func (jwt *JWT) Invalidate(t *Token) error {
 	switch {
 	case exp == 0:
 		return ErrMissingExp
-	case time.Now().UTC().Unix() > exp:
+	case Now() > exp:
 		return ErrExp
 	}
 	if !hmac.Equal(jwt.sum(t.Data(), h), t.RawSig()) {
@@ -190,12 +190,12 @@ func (jwt *JWT) Sign(t *Token) (err error) {
 	if h == nil {
 		return ErrUnsupportedAlg
 	}
-	now := time.Now().UTC()
+	now := time.Now()
 	if _, ok := t.Claims.Get(ExpClaim); !ok {
-		t.Claims.Set(ExpClaim, now.Add(jwt.expiry).Unix())
+		t.Claims.Set(ExpClaim, newExp(now, jwt.expiry))
 	}
 	if _, ok := t.Claims.Get(NbfClaim); !ok {
-		t.Claims.Set(NbfClaim, now.Unix())
+		t.Claims.Set(NbfClaim, NewNbf(now))
 	}
 	head, err := json.Marshal(t.Header)
 	if err != nil {
@@ -222,7 +222,7 @@ func (jwt *JWT) Verify(t *Token) error {
 			return err
 		}
 	}
-	now := time.Now().UTC().Unix()
+	now := Now()
 	if t.Header.GetString(TypClaim) != Typ {
 		return ErrNoJWT
 	}

time.go

@@ -0,0 +1,22 @@
+package jwt
+
+import "time"
+
+// Now returns the current time in UTC Unix format
+func Now() int64 {
+	return NewNbf(time.Now())
+}
+
+// NewNbf returns a new 'not before' date
+func NewNbf(t time.Time) int64 {
+	return t.UTC().Unix()
+}
+
+// NewExp returns a new expiration date
+func NewExp(d time.Duration) int64 {
+	return newExp(time.Now(), d)
+}
+
+func newExp(t time.Time, d time.Duration) int64 {
+	return t.UTC().Add(d).Unix()
+}