fix the chat.Message with empty Text and Extra message doesn't contain an empty "text" field after marshaled into json. close #151

chat/message.go

@@ -43,7 +43,7 @@ const (
 
 // Message is a message sent by other
 type Message struct {
-	Text string `json:"text,omitempty"`
+	Text string `json:"text"`
 
 	Bold          bool `json:"bold,omitempty"`          //粗体
 	Italic        bool `json:"italic,omitempty"`        //斜体
@@ -67,8 +67,38 @@ type Message struct {
 	Extra     []Message         `json:"extra,omitempty"`
 }
 
+// Same as Message, but "Text" is omitempty
+type translateMsg struct {
+	Text string `json:"text,omitempty"`
+
+	Bold          bool `json:"bold,omitempty"`
+	Italic        bool `json:"italic,omitempty"`
+	UnderLined    bool `json:"underlined,omitempty"`
+	StrikeThrough bool `json:"strikethrough,omitempty"`
+	Obfuscated    bool `json:"obfuscated,omitempty"`
+
+	Font  string `json:"font,omitempty"`
+	Color string `json:"color,omitempty"`
+
+	Insertion  string      `json:"insertion,omitempty"`
+	ClickEvent *ClickEvent `json:"clickEvent,omitempty"`
+	HoverEvent *HoverEvent `json:"hoverEvent,omitempty"`
+
+	Translate string            `json:"translate"`
+	With      []json.RawMessage `json:"with,omitempty"`
+	Extra     []Message         `json:"extra,omitempty"`
+}
+
 type jsonMsg Message
 
+func (m Message) MarshalJSON() ([]byte, error) {
+	if m.Translate != "" {
+		return json.Marshal(translateMsg(m))
+	} else {
+		return json.Marshal(jsonMsg(m))
+	}
+}
+
 //UnmarshalJSON decode json to Message
 func (m *Message) UnmarshalJSON(raw []byte) (err error) {
 	if len(raw) == 0 {

chat/message_test.go

@@ -2,7 +2,9 @@ package chat_test
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
+	"strings"
 	"testing"
 
 	"github.com/Tnze/go-mc/chat"
@@ -134,6 +136,31 @@ func TestMessage_Append_issue148(t *testing.T) {
 	}
 }
 
+func TestMessage_MarshalJSON_issue151(t *testing.T) {
+	// The "text" field should be omitted when "translate" exist.
+	// And NOT omitted when "extra" so.
+	// That is, we should correctly generate these chat messages:
+	// {"text":"","extra":["str1", "str2"]} and
+	// {"translate":"translation.test.escape","with":["str1","str2"]}
+	mustJson := func(msg *chat.Message) string {
+		data, err := json.Marshal(msg)
+		if err != nil {
+			t.Fatal(err)
+		}
+		return string(data)
+	}
+	// "" + "Hello, world!"
+	msg1 := chat.Text("").Append(chat.TranslateMsg("translation.test.none"))
+	if msg := mustJson(&msg1); !strings.Contains(msg, "text") {
+		t.Fatalf("%s doesn't contain %s", msg, "text")
+	}
+	//
+	msg2 := chat.TranslateMsg("translation.test.none")
+	if msg := mustJson(&msg2); strings.Contains(msg, "text") {
+		t.Fatalf("%s contains %s", msg, "text")
+	}
+}
+
 func ExampleTranslateMsg() {
 	fmt.Println(chat.TranslateMsg("translation.test.none"))
 	fmt.Println(chat.TranslateMsg(