结合服务端和客户端使用protobuf

前段页面引入这三个文件，主要用来按照protobuf buffer协议解编码protobuf数据。

<script src="../protobuf/long.js"></script><script src="../protobuf/bytebuffer.js"></script><script src="../protobuf/protobuf.js"></script>

先写一份说明书-proto文件，test.protobuf

package TestProtobuf;option java_package = "com.why.game.protobuf";option java_outer_classname = "TestProtobuf";message TestProto{    optional int32 id = 1;    optional string name = 2;}

使用库文件加载这个proto文件

var ProtoBuf = dcodeIO.ProtoBuf;var TestProtobuf = ProtoBuf.loadProtoFile("test.proto").build("TestProtobuf");

//的到里面的messagevar TestProto = TestProtobuf.TestProto;

用ajax发送/接收protobuf：

xhr.onreadystatechange = function(){    if (xhr.readyState == 4 && xhr.status == 200) {        var data = xhr.responseText;

//解码protobuf        var protobufResp = TestProto.decode(str2bytes(data));        var jsonResp = JSON.stringify(protobufResp);        console.log(jsonResp);    }};//实例化一个TestProtovar testProto = new TestProto({    id:10014,    name:"testProtoName测试987"});

//编码发送xhr.send(testProto.toBuffer())

使用XMLHttpRequest对象的send方法发送经由TestProto编码（encode）后的buffer数组（本质也是二进制字节流），

接收的时候同样使用TestProto解码（decode）接收到的二进制数据

这里因为浏览器会把Ajax返回的二进制数据当做文本数据，所以写个str2bytes方法把接收到的文本数据按字节一个个做与运算来还原成二进制byte

function str2bytes(str){    var bytes = [];    for (var i = 0, len = str.length; i < len; ++i) {        var c = str.charCodeAt(i);        var byte = c & 0xff;        bytes.push(byte);    }    return bytes;}

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使用socketio：

客户端

<script type="text/javascript" src="socket.io.js"></script>

//写个example.proto

//注意这个message是关键字

message Message {    required string text = 1;}

//客户端js

var ProtoBuf = dcodeIO.ProtoBuf;var Message = ProtoBuf.loadProtoFile("./example.proto").build("Message");var log = {
value:''
}// socket链接服务器var socket = io.connect("http://localhost:3000");socket.on("connect", function () {    log.value += "Connected\n";});socket.on("disconnect", function () {    log.value += "Disconnected\n";});socket.on("message", function (message) {    try{
//解析服务端数据        var msg = Message.decode(message);        log.value += "Received: " + msg.text + "\n";    }catch(err){        log.value += "Error: " + err + "\n";    }});function send() {    if (socket.connected) {
//向服务端发送数据        var msg = new Message({text:3});        socket.send(msg.toBuffer());        log.value += "Sent: " + msg.text + "\n";    } else {        log.value += "Not connected\n";    }}

//服务端nodejs部分：

同样需要
protobufjs
var server = http.createServer(function(request, response){    var filePath = false;    if(request.url == "/"){        filePath = "index.html";    }else if(request.method === "POST"){        if(request.url.indexOf("protobuf") != -1){            //BufferHelper参考链接 http://www.infoq.com/cn/articles/nodejs-about-buffer/            var bufferHelper = new BufferHelper();            request.on("data", function (chunk) {                bufferHelper.concat(chunk);            });            request.on("end", function () {                var buffer = bufferHelper.toBuffer();                var testProtoData = TestProto.decode(buffer);                response.writeHead(200, {"Content-Type": "application/x-protobuf"});                response.end(testProtoData.toBuffer());            });        }        return;    }else{        filePath = request.url;    }    var absPath = webRoot+filePath;    serveStatic(response, cache, absPath);});

var ProtoBuf = require("protobufjs");var socketio = require("socket.io");// Initialize from .proto filevar builder = ProtoBuf.loadProtoFile(path.join(__dirname, "www", "example.proto")),    Message = builder.build("Message");// SocketIO adaptervar io = socketio.listen(server);io.set("log level", 1);io.sockets.on("connection", function(socket){    console.log(socket.id+" connecting...");    socket.on("disconnect", function() {        console.log("WebSocket disconnected");    });    socket.on("message", function(data) {        try {            // Decode the Message            var msg = Message.decode(data);            console.log("Received: "+msg.text);            // Transform the text to upper case            msg.text = msg.text.toUpperCase();            // Re-encode it and send it back            socket.send(msg.toBuffer());            //socket.emit('message', msg.toBuffer());            console.log("Sent: "+msg.text);        } catch (err) {            console.log("Processing failed:", err);        }    });});
ok