javascript之ProtoBuf在websocket中的使用
阿新 • • 發佈：2017-07-20
java
因為ProtoBuf的序列化效率和大小都非常好，所以它在網絡通信上面應用越來越多；而webosocket也隨著web3.0應用越來越廣泛，而將這兩個結合在一起的也會慢慢形成一種趨勢；本人是為了測試自已寫的一個C# websocket，所以在web上面結合pb也寫了一個js實例:
1.首先下載protobuf.js
2.引入protobuf相關js文件
<script src="/js/protobuf.js"></script>
3.創建proto文件
1 package wenlipackage;2 syntax = "proto3";3 4 message WSMessage {
5 required string id = 1;6 required string content = 2;7 required string sender = 3;8 required string time = 4;9 }
js的protobuf格式類型有
| Field type | Expected JS type (create, encode) | Conversion (fromObject) |
|---|---|---|
| s-/u-/int32 s-/fixed32 | number (32 bit integer) | value | 0 if signedvalue >>> 0 if unsigned |
| s-/u-/int64 s-/fixed64 | Long-like (optimal)number (53 bit integer) | Long.fromValue(value) with long.jsparseInt(value, 10) otherwise |
| float double | number | Number(value) |
| bool | boolean | Boolean(value) |
| string | string | String(value) |
| bytes | Uint8Array (optimal)Buffer (optimal under node)Array.<number> (8 bit integers) | base64.decode(value) if a stringObject with non-zero .length is assumed to be buffer-like |
| enum | number (32 bit integer) | Looks up the numeric id if a string |
| message | Valid message | Message.fromObject(value) |
4.初始化protobuf，對相關數據進行序列化和反序列化
1 <script type="text/javascript">
2 var WSMessage;
3 var wsmessage;
4 var buffer;
5 protobuf.load("/proto/Message.proto", function (err, root) {
6 if (err) throw err;
7 WSMessage = root.lookup("wenlipackage.WSMessage");
8 wsmessage = WSMessage.create({ id: "1", content: "hello", sender: "web", time: new Date().getTime() });
9 buffer = WSMessage.encode(wsmessage).finish();
10 });
11 </script>
WSMessage是一個解碼編碼器
wsmessage是具體的某個定義的proto實例 是一個8位無符號的字節數組
5.連接到websocket並發送序列化的消息和接收反序列化的消息
1 <script type="text/javascript"> 2 var wsUri = "ws://127.0.0.1:8082/"; 3 var output; 4 function init() { 5 output = document.getElementById("output"); 6 testWebSocket(); 7 } 8 function testWebSocket() { 9 websocket = new WebSocket(wsUri);10 websocket.onopen = function (evt) {11 onOpen(evt)12 };13 websocket.onclose = function (evt) {14 onClose(evt)15 };16 websocket.onmessage = function (evt) {17 onMessage(evt)18 };19 websocket.onerror = function (evt) {20 onError(evt)21 };22 }23 function onOpen(evt) {24 writeToScreen("CONNECTED");25 doSend(buffer);26 }27 function onClose(evt) {28 writeToScreen("DISCONNECTED");29 }30 function onMessage(evt) {31 var reader = new FileReader();32 reader.readAsArrayBuffer(evt.data);33 reader.onload = function (e) {34 var buf = new Uint8Array(reader.result);35 writeToScreen(‘<span style="color: blue;">RESPONSE: ‘ + WSMessage.decode(buf).content + ‘</span>‘);36 }37 }38 function onError(evt) {39 writeToScreen(‘<span style="color: red;">ERROR:</span> ‘ + evt.data);40 }41 function doSend(message) {42 writeToScreen("SENT: " + wsmessage.content);43 websocket.send(buffer);44 }45 function writeToScreen(message) {46 var pre = document.createElement("p");47 pre.style.wordWrap = "break-word";48 pre.innerHTML = message;49 output.appendChild(pre);50 }51 window.addEventListener("load", init, false);52 </script>
上面因為我的websocket server 返回一是二進制，所以瀏覽器接收到的是一個blob，這裏註意對blob的處理
6.互通測試
javascript之ProtoBuf在websocket中的使用