add protobuf binding for gin

binding/binding.go

@@ -14,6 +14,7 @@ const (
 	MIMEPlain             = "text/plain"
 	MIMEPOSTForm          = "application/x-www-form-urlencoded"
 	MIMEMultipartPOSTForm = "multipart/form-data"
+	MIMEPROTOBUF          = "application/octet-stream"
 )
 
 type Binding interface {
@@ -33,9 +34,10 @@ type StructValidator interface {
 var Validator StructValidator = &defaultValidator{}
 
 var (
-	JSON = jsonBinding{}
-	XML  = xmlBinding{}
-	Form = formBinding{}
+	JSON     = jsonBinding{}
+	XML      = xmlBinding{}
+	Form     = formBinding{}
+	ProtoBuf = protobufBinding{}
 )
 
 func Default(method, contentType string) Binding {
@@ -47,6 +49,8 @@ func Default(method, contentType string) Binding {
 			return JSON
 		case MIMEXML, MIMEXML2:
 			return XML
+		case MIMEPROTOBUF:
+			return ProtoBuf
 		default: //case MIMEPOSTForm, MIMEMultipartPOSTForm:
 			return Form
 		}