fix v1 handler: use create command when test against prevexistence

server/v1/set_key_handler.go

@@ -30,12 +30,20 @@ func SetKeyHandler(w http.ResponseWriter, req *http.Request, s Server) error {
 
 	// If the "prevValue" is specified then test-and-set. Otherwise create a new key.
 	var c raft.Command
-	if prevValueArr, ok := req.Form["prevValue"]; ok && len(prevValueArr) > 0 {
-		c = &store.CompareAndSwapCommand{
-			Key:        key,
-			Value:      value,
-			PrevValue:  prevValueArr[0],
-			ExpireTime: expireTime,
+	if prevValueArr, ok := req.Form["prevValue"]; ok {
+		if len(prevValueArr) > 0 { // test against previous value
+			c = &store.CompareAndSwapCommand{
+				Key:        key,
+				Value:      value,
+				PrevValue:  prevValueArr[0],
+				ExpireTime: expireTime,
+			}
+		} else {
+			c = &store.CreateCommand{ // test against existence
+				Key:        key,
+				Value:      value,
+				ExpireTime: expireTime,
+			}
 		}
 
 	} else {

store/event.go

@@ -55,13 +55,16 @@ func (event *Event) Response() interface{} {
 			Expiration: event.Expiration,
 		}
 
-		if response.Action == Create || response.Action == Set {
-			response.Action = "set"
+		if response.Action == Set {
 			if response.PrevValue == "" {
 				response.NewKey = true
 			}
 		}
 
+		if response.Action == CompareAndSwap || response.Action == Create {
+			response.Action = "testAndSet"
+		}
+
 		return response
 	} else {
 		responses := make([]*Response, len(event.KVPairs))