Introduce (*Parser).ParseUnverified

parser.go

@@ -21,55 +21,9 @@ func (p *Parser) Parse(tokenString string, keyFunc Keyfunc) (*Token, error) {
 }
 
 func (p *Parser) ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc) (*Token, error) {
-	parts := strings.Split(tokenString, ".")
-	if len(parts) != 3 {
-		return nil, NewValidationError("token contains an invalid number of segments", ValidationErrorMalformed)
-	}
-
-	var err error
-	token := &Token{Raw: tokenString}
-
-	// parse Header
-	var headerBytes []byte
-	if headerBytes, err = DecodeSegment(parts[0]); err != nil {
-		if strings.HasPrefix(strings.ToLower(tokenString), "bearer ") {
-			return token, NewValidationError("tokenstring should not contain 'bearer '", ValidationErrorMalformed)
-		}
-		return token, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
-	}
-	if err = json.Unmarshal(headerBytes, &token.Header); err != nil {
-		return token, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
-	}
-
-	// parse Claims
-	var claimBytes []byte
-	token.Claims = claims
-
-	if claimBytes, err = DecodeSegment(parts[1]); err != nil {
-		return token, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
-	}
-	dec := json.NewDecoder(bytes.NewBuffer(claimBytes))
-	if p.UseJSONNumber {
-		dec.UseNumber()
-	}
-	// JSON Decode.  Special case for map type to avoid weird pointer behavior
-	if c, ok := token.Claims.(MapClaims); ok {
-		err = dec.Decode(&c)
-	} else {
-		err = dec.Decode(&claims)
-	}
-	// Handle decode error
+	token, parts, err := p.ParseUnverified(tokenString, claims)
 	if err != nil {
-		return token, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
-	}
-
-	// Lookup signature method
-	if method, ok := token.Header["alg"].(string); ok {
-		if token.Method = GetSigningMethod(method); token.Method == nil {
-			return token, NewValidationError("signing method (alg) is unavailable.", ValidationErrorUnverifiable)
-		}
-	} else {
-		return token, NewValidationError("signing method (alg) is unspecified.", ValidationErrorUnverifiable)
+		return token, err
 	}
 
 	// Verify signing method is in the required set
@@ -129,3 +83,63 @@ func (p *Parser) ParseWithClaims(tokenString string, claims Claims, keyFunc Keyf
 
 	return token, vErr
 }
+
+// WARNING: Don't use this method unless you know what you're doing
+//
+// This method parses the token but doesn't validate the signature. It's only
+// ever useful in cases where you know the signature is valid (because it has
+// been checked previously in the stack) and you want to extract values from
+// it.
+func (p *Parser) ParseUnverified(tokenString string, claims Claims) (token *Token, parts []string, err error) {
+	parts = strings.Split(tokenString, ".")
+	if len(parts) != 3 {
+		return nil, parts, NewValidationError("token contains an invalid number of segments", ValidationErrorMalformed)
+	}
+
+	token = &Token{Raw: tokenString}
+
+	// parse Header
+	var headerBytes []byte
+	if headerBytes, err = DecodeSegment(parts[0]); err != nil {
+		if strings.HasPrefix(strings.ToLower(tokenString), "bearer ") {
+			return token, parts, NewValidationError("tokenstring should not contain 'bearer '", ValidationErrorMalformed)
+		}
+		return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
+	}
+	if err = json.Unmarshal(headerBytes, &token.Header); err != nil {
+		return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
+	}
+
+	// parse Claims
+	var claimBytes []byte
+	token.Claims = claims
+
+	if claimBytes, err = DecodeSegment(parts[1]); err != nil {
+		return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
+	}
+	dec := json.NewDecoder(bytes.NewBuffer(claimBytes))
+	if p.UseJSONNumber {
+		dec.UseNumber()
+	}
+	// JSON Decode.  Special case for map type to avoid weird pointer behavior
+	if c, ok := token.Claims.(MapClaims); ok {
+		err = dec.Decode(&c)
+	} else {
+		err = dec.Decode(&claims)
+	}
+	// Handle decode error
+	if err != nil {
+		return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
+	}
+
+	// Lookup signature method
+	if method, ok := token.Header["alg"].(string); ok {
+		if token.Method = GetSigningMethod(method); token.Method == nil {
+			return token, parts, NewValidationError("signing method (alg) is unavailable.", ValidationErrorUnverifiable)
+		}
+	} else {
+		return token, parts, NewValidationError("signing method (alg) is unspecified.", ValidationErrorUnverifiable)
+	}
+
+	return token, parts, nil
+}

parser_test.go

@@ -247,6 +247,46 @@ func TestParser_Parse(t *testing.T) {
 	}
 }
 
+func TestParser_ParseUnverified(t *testing.T) {
+	privateKey := test.LoadRSAPrivateKeyFromDisk("test/sample_key")
+
+	// Iterate over test data set and run tests
+	for _, data := range jwtTestData {
+		// If the token string is blank, use helper function to generate string
+		if data.tokenString == "" {
+			data.tokenString = test.MakeSampleToken(data.claims, privateKey)
+		}
+
+		// Parse the token
+		var token *jwt.Token
+		var err error
+		var parser = data.parser
+		if parser == nil {
+			parser = new(jwt.Parser)
+		}
+		// Figure out correct claims type
+		switch data.claims.(type) {
+		case jwt.MapClaims:
+			token, _, err = parser.ParseUnverified(data.tokenString, jwt.MapClaims{})
+		case *jwt.StandardClaims:
+			token, _, err = parser.ParseUnverified(data.tokenString, &jwt.StandardClaims{})
+		}
+
+		if err != nil {
+			t.Errorf("[%v] Invalid token")
+		}
+
+		// Verify result matches expectation
+		if !reflect.DeepEqual(data.claims, token.Claims) {
+			t.Errorf("[%v] Claims mismatch. Expecting: %v  Got: %v", data.name, data.claims, token.Claims)
+		}
+
+		if data.valid && err != nil {
+			t.Errorf("[%v] Error while verifying token: %T:%v", data.name, err, err)
+		}
+	}
+}
+
 // Helper method for benchmarking various methods
 func benchmarkSigning(b *testing.B, method jwt.SigningMethod, key interface{}) {
 	t := jwt.New(method)