Supporting dynamic data response for single object

Author: Derek Dowling

list.go

@@ -30,15 +30,15 @@ interface.
 func (list *List) UnmarshalJSON(rawData []byte) error {
 	// Create a sub-type here so when we call Unmarshal below, we don't recursively
 	// call this function over and over
-	type MarshalList List
+	type UnmarshalList List
 
 	// if our "List" is a single object, modify the JSON to make it into a list
 	// by wrapping with "[ ]"
 	if rawData[0] == '{' {
 		rawData = []byte(fmt.Sprintf("[%s]", rawData))
 	}
 
-	newList := MarshalList{}
+	newList := UnmarshalList{}
 
 	err := json.Unmarshal(rawData, &newList)
 	if err != nil {
@@ -50,3 +50,21 @@ func (list *List) UnmarshalJSON(rawData []byte) error {
 
 	return nil
 }
+
+/*
+MarshalJSON returns a top level object for the "data" attribute if a single object. In
+all other cases returns a JSON encoded list for "data".
+*/
+func (list List) MarshalJSON() ([]byte, error) {
+	// avoid stack overflow by using this subtype for marshaling
+	type MarshalList List
+	marshalList := MarshalList(list)
+	count := len(marshalList)
+
+	switch {
+	case count == 1:
+		return json.Marshal(marshalList[0])
+	default:
+		return json.Marshal(marshalList)
+	}
+}