Home >Web Front-end >JS Tutorial >Detailed explanation of downloading and using protobuf.js
Because ProtoBuf's serialization efficiency and size are very good, it is used more and more in network communications; and webosocket is becoming more and more widely used as web3.0, and the combination of the two Together they will gradually form a trend; I wanted to test a C# websocket I wrote, so I also wrote a js example on the web combined with pb:
1. First download protobuf.js
2. Introduce protobuf related js files
3. Create proto file
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 }
The protobuf format type of js is
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 |
double |
number
|
Number(value)
|
boolean |
| Boolean(value)
|
string |
| String(value)
|
Uint8Array | (optimal) Buffer(optimal under node) Array.(8 bit integers)
| base64.decode(value) if a string Objectwith non-zero .length is assumed to be buffer-like
|
number | (32 bit integer) Looks up the numeric id if a | string
|
Valid message | Message.fromObject(value) |
|
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是一个解码编码器
wsmessage是具体的某个定义的proto实例 是一个8位无符号的字节数组5. Connect to websocket and send serialized message and receive Deserialized message
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 };
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);
}27 function onClose(evt) {28 writeToScreen("DISCONNECTED");29 }30 function onMessage(evt) {31 var reader = new FileReader();32 reader.readAsArrayBuffer(evt.data);
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>
6. Interoperability test
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