Added timeFunc, made iat optional

example_test.go

@@ -95,7 +95,7 @@ func ExampleParseWithClaims_customClaimsType() {
 
 // Example creating a token using a custom claims type and validation options.  The RegisteredClaims is embedded
 // in the custom type to allow for easy encoding, parsing and validation of standard claims.
-func ExampleParseWithClaims_customValidator() {
+func ExampleParseWithClaims_validationOptions() {
 	tokenString := "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJpc3MiOiJ0ZXN0IiwiYXVkIjoic2luZ2xlIn0.QAWg1vGvnqRuCFTMcPkjZljXHh8U3L_qUjszOtQbeaA"
 
 	type MyCustomClaims struct {
@@ -117,7 +117,41 @@ func ExampleParseWithClaims_customValidator() {
 	// Output: bar test
 }
 
-// An example of parsing the error types using bitfield checks
+type MyCustomClaims struct {
+	Foo string `json:"foo"`
+	jwt.RegisteredClaims
+}
+
+func (m MyCustomClaims) CustomValidation() error {
+	if m.Foo != "bar" {
+		return errors.New("must be foobar")
+	}
+
+	return nil
+}
+
+// Example creating a token using a custom claims type and validation options.
+// The RegisteredClaims is embedded in the custom type to allow for easy
+// encoding, parsing and validation of standard claims and the function
+// CustomValidation is implemented.
+func ExampleParseWithClaims_customValidation() {
+	tokenString := "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJpc3MiOiJ0ZXN0IiwiYXVkIjoic2luZ2xlIn0.QAWg1vGvnqRuCFTMcPkjZljXHh8U3L_qUjszOtQbeaA"
+
+	validator := jwt.NewValidator(jwt.WithLeeway(5 * time.Second))
+	token, err := jwt.ParseWithClaims(tokenString, &MyCustomClaims{}, func(token *jwt.Token) (interface{}, error) {
+		return []byte("AllYourBase"), nil
+	}, jwt.WithValidator(validator))
+
+	if claims, ok := token.Claims.(*MyCustomClaims); ok && token.Valid {
+		fmt.Printf("%v %v", claims.Foo, claims.RegisteredClaims.Issuer)
+	} else {
+		fmt.Println(err)
+	}
+
+	// Output: bar test
+}
+
+// An example of parsing the error types using errors.Is.
 func ExampleParse_errorChecking() {
 	// Token from another example.  This token is expired
 	var tokenString = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJleHAiOjE1MDAwLCJpc3MiOiJ0ZXN0In0.HE7fK0xOQwFEr4WDgRWj4teRPZ6i3GLwD5YCm6Pwu_c"

parser.go

@@ -7,6 +7,9 @@ import (
 	"strings"
 )
 
+// DefaultValidator is the default validator that is used, if no custom validator is supplied in a Parser.
+var DefaultValidator = NewValidator()
+
 type Parser struct {
 	// If populated, only these methods will be considered valid.
 	//
@@ -28,12 +31,9 @@ type Parser struct {
 
 // NewParser creates a new Parser with the specified options
 func NewParser(options ...ParserOption) *Parser {
-	p := &Parser{
+	p := &Parser{}
-		// Supply a default validator
-		validator: NewValidator(),
-	}
 
-	// loop through our parsing options and apply them
+	// Loop through our parsing options and apply them
 	for _, option := range options {
 		option(p)
 	}
@@ -89,7 +89,7 @@ func (p *Parser) ParseWithClaims(tokenString string, claims Claims, keyFunc Keyf
 	if !p.SkipClaimsValidation {
 		// Make sure we have at least a default validator
 		if p.validator == nil {
-			p.validator = NewValidator()
+			p.validator = DefaultValidator
 		}
 
 		if err := p.validator.Validate(claims); err != nil {

token.go

@@ -4,7 +4,6 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"strings"
-	"time"
 )
 
 // DecodePaddingAllowed will switch the codec used for decoding JWTs respectively. Note that the JWS RFC7515
@@ -14,11 +13,6 @@ import (
 // To use the non-recommended decoding, set this boolean to `true` prior to using this package.
 var DecodePaddingAllowed bool
 
-// TimeFunc provides the current time when parsing token to validate "exp" claim (expiration time).
-// You can override it to use another time value.  This is useful for testing or if your
-// server uses a different time zone than your tokens.
-var TimeFunc = time.Now
-
 // Keyfunc will be used by the Parse methods as a callback function to supply
 // the key for verification.  The function receives the parsed,
 // but unverified Token.  This allows you to use properties in the

validator.go

@@ -6,13 +6,48 @@ import (
 	"time"
 )
 
+// Validator is the core of the new Validation API. It is
 type Validator struct {
+	// leeway is an optional leeway that can be provided to account for clock skew.
 	leeway time.Duration
+
+	// timeFunc is used to supply the current time that is needed for
+	// validation. If unspecified, this defaults to time.Now.
+	timeFunc func() time.Time
+
+	// verifyIat specifies whether the iat (Issued At) claim will be verified.
+	// According to https://www.rfc-editor.org/rfc/rfc7519#section-4.1.6 this
+	// only specifies the age of the token, but no validation check is
+	// necessary. However, if wanted, it can be checked if the iat is
+	// unrealistic, i.e., in the future.
+	verifyIat bool
+}
+
+type customValidationType interface {
+	CustomValidation() error
+}
+
+func NewValidator(opts ...ValidatorOption) *Validator {
+	v := &Validator{}
+
+	// Apply the validator options
+	for _, o := range opts {
+		o(v)
+	}
+
+	return v
 }
 
 func (v *Validator) Validate(claims Claims) error {
+	var now time.Time
 	vErr := new(ValidationError)
-	now := TimeFunc()
+
+	// Check, if we have a time func
+	if v.timeFunc != nil {
+		now = v.timeFunc()
+	} else {
+		now = time.Now()
+	}
 
 	if !v.VerifyExpiresAt(claims, now, false) {
 		exp := claims.GetExpirationTime()
@@ -21,7 +56,8 @@ func (v *Validator) Validate(claims Claims) error {
 		vErr.Errors |= ValidationErrorExpired
 	}
 
-	if !v.VerifyIssuedAt(claims, now, false) {
+	// Check iat if the option is enabled
+	if v.verifyIat && !v.VerifyIssuedAt(claims, now, false) {
 		vErr.Inner = ErrTokenUsedBeforeIssued
 		vErr.Errors |= ValidationErrorIssuedAt
 	}
@@ -31,6 +67,16 @@ func (v *Validator) Validate(claims Claims) error {
 		vErr.Errors |= ValidationErrorNotValidYet
 	}
 
+	// Finally, we want to give the claim itself some possibility to do some
+	// additional custom validation based on their custom claims
+	cvt, ok := claims.(customValidationType)
+	if ok {
+		if err := cvt.CustomValidation(); err != nil {
+			vErr.Inner = err
+			vErr.Errors |= ValidationErrorClaimsInvalid
+		}
+	}
+
 	if vErr.valid() {
 		return nil
 	}
@@ -83,16 +129,6 @@ func (v *Validator) VerifyIssuer(claims Claims, cmp string, req bool) bool {
 	return verifyIss(claims.GetIssuer(), cmp, req)
 }
 
-func NewValidator(opts ...ValidatorOption) *Validator {
-	v := &Validator{}
-
-	for _, o := range opts {
-		o(v)
-	}
-
-	return v
-}
-
 // ----- helpers
 
 func verifyAud(aud []string, cmp string, required bool) bool {

validator_option.go

@@ -9,9 +9,26 @@ import "time"
 // accordingly.
 type ValidatorOption func(*Validator)
 
-// WithLeeway returns the ParserOption for specifying the leeway window.
+// WithLeeway returns the ValidatorOption for specifying the leeway window.
 func WithLeeway(leeway time.Duration) ValidatorOption {
 	return func(v *Validator) {
 		v.leeway = leeway
 	}
 }
+
+// WithTimeFunc returns the ValidatorOption for specifying the time func. The
+// primary use-case for this is testing. If you are looking for a way to account
+// for clock-skew, WithLeeway should be used instead.
+func WithTimeFunc(f func() time.Time) ValidatorOption {
+	return func(v *Validator) {
+		v.timeFunc = f
+	}
+}
+
+// WithIssuedAtVerification returns the ValidatorOption to enable verification
+// of issued-at.
+func WithIssuedAtVerification() ValidatorOption {
+	return func(v *Validator) {
+		v.verifyIat = true
+	}
+}