added example of parsing using custom type

example_test.go

@@ -3,6 +3,7 @@ package jwt_test
 import (
 	"fmt"
 	"github.com/dgrijalva/jwt-go"
+	"time"
 )
 
 // Example (atypical) using the StandardClaims type by itself to parse a token.
@@ -25,7 +26,7 @@ func ExampleNewWithClaims_standardClaims() {
 	//Output: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE1MDAwLCJpc3MiOiJ0ZXN0In0.QsODzZu3lUZMVdhbO76u3Jv02iYCvEHcYVUI1kOWEU0 <nil>
 }
 
-// Example parsing a token using a custom claims type.  The StandardClaim is embedded
+// Example creating a token using a custom claims type.  The StandardClaim is embedded
 // in the custom type to allow for easy encoding, parsing and validation of standard claims.
 func ExampleNewWithClaims_customClaimsType() {
 	mySigningKey := []byte("AllYourBase")
@@ -50,6 +51,41 @@ func ExampleNewWithClaims_customClaimsType() {
 	//Output: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJleHAiOjE1MDAwLCJpc3MiOiJ0ZXN0In0.HE7fK0xOQwFEr4WDgRWj4teRPZ6i3GLwD5YCm6Pwu_c <nil>
 }
 
+// Example creating a token using a custom claims type.  The StandardClaim is embedded
+// in the custom type to allow for easy encoding, parsing and validation of standard claims.
+func ExampleParseWithClaims_customClaimsType() {
+	tokenString := "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJleHAiOjE1MDAwLCJpc3MiOiJ0ZXN0In0.HE7fK0xOQwFEr4WDgRWj4teRPZ6i3GLwD5YCm6Pwu_c"
+
+	type MyCustomClaims struct {
+		Foo string `json:"foo"`
+		jwt.StandardClaims
+	}
+
+	// sample token is expired.  override time so it parses as valid
+	at(time.Unix(0, 0), func() {
+		token, err := jwt.ParseWithClaims(tokenString, func(token *jwt.Token) (interface{}, error) {
+			return []byte("AllYourBase"), nil
+		}, &MyCustomClaims{})
+
+		if claims, ok := token.Claims.(*MyCustomClaims); ok && token.Valid {
+			fmt.Printf("%v %v", claims.Foo, claims.StandardClaims.ExpiresAt)
+		} else {
+			fmt.Println(err)
+		}
+	})
+
+	// Output: bar 15000
+}
+
+// Override time value for tests.  Restore default value after.
+func at(t time.Time, f func()) {
+	jwt.TimeFunc = func() time.Time {
+		return t
+	}
+	f()
+	jwt.TimeFunc = time.Now
+}
+
 // An example of parsing the error types using bitfield checks
 func ExampleParse_errorChecking() {
 	// Token from another example.  This token is expired