[feature] NopEncoder: accept/return []byte.

[feature] NopEncoder: accept/return []byte.

2 files changed, 26 insertions, 1 deletions

diff --git a/doc.go b/doc.go
index e80e3ae..ae89408 100644
--- a/doc.go
+++ b/doc.go
@@ -3,7 +3,7 @@
 // license that can be found in the LICENSE file.
 
 /*
-Package gorilla/securecookie encodes and decodes authenticated and optionally
+Package securecookie encodes and decodes authenticated and optionally
 encrypted cookie values.
 
 Secure cookies can't be forged, because their values are validated using HMAC.
diff --git a/securecookie.go b/securecookie.go
index be43e9d..83dd606 100644
--- a/securecookie.go
+++ b/securecookie.go
@@ -101,6 +101,7 @@ var (
 	errTimestampTooNew      = cookieError{typ: decodeError, msg: "timestamp is too new"}
 	errTimestampExpired     = cookieError{typ: decodeError, msg: "expired timestamp"}
 	errDecryptionFailed     = cookieError{typ: decodeError, msg: "the value could not be decrypted"}
+	errValueNotByte         = cookieError{typ: decodeError, msg: "value not a []byte."}
 
 	// ErrMacInvalid indicates that cookie decoding failed because the HMAC
 	// could not be extracted and verified.  Direct use of this error
@@ -181,6 +182,11 @@ type GobEncoder struct{}
 // json.Unmarshaller interfaces.
 type JSONEncoder struct{}
 
+// NopEncoder does not encode cookie values, and instead simply accepts a []byte
+// (as an interface{}) and returns a []byte. This is particularly useful when
+// you encoding an object upstream and do not wish to re-encode it.
+type NopEncoder struct{}
+
 // MaxLength restricts the maximum length, in bytes, for the cookie value.
 //
 // Default is 4096, which is the maximum value accepted by Internet Explorer.
@@ -457,6 +463,25 @@ func (e JSONEncoder) Deserialize(src []byte, dst interface{}) error {
 	return nil
 }
 
+// Serialize passes a []byte through as-is.
+func (e NopEncoder) Serialize(src interface{}) ([]byte, error) {
+	if b, ok := src.([]byte); ok {
+		return b, nil
+	}
+
+	return nil, errValueNotByte
+}
+
+// Deserialize passes a []byte through as-is.
+func (e NopEncoder) Deserialize(src []byte, dst interface{}) error {
+	if _, ok := dst.([]byte); ok {
+		dst = src
+		return nil
+	}
+
+	return errValueNotByte
+}
+
 // Encoding -------------------------------------------------------------------
 
 // encode encodes a value using base64.