javascript - 使用 WebSocket 传递二进制数据

Question

我正在编写一个 Firefox 扩展，并且正在搜索使用 WebSocket 传递压缩文件(服务器 here )。客户端(发送文件)的代码如下:

var ws = new window.WebSocket("ws://localhost:12345");

function sendLogToOtherClient(file){

   var zippedFileToSend = zipLogFile(file);
   NetUtil.asyncFetch(zippedFileToSend, function(inputStream, status) {
      if (!components.isSuccessCode(status)) {
         return;
   }
   var bstream = Cc["@mozilla.org/binaryinputstream;1"].createInstance(Ci.nsIBinaryInputStream);
   bstream.setInputStream(inputStream);
   var bytes = bstream.readByteArray(bstream.available());
   bstream.close();
   var encodedData = base64.encode(bytes, "utf-8");
   ws.send(encodedData);
   });
}
function zipLogFile(fileToZip){
   var zippedFile = FileUtils.getFile("ProfD", ["report1.zip"], false);
   var zipWriter = CCIN("@mozilla.org/zipwriter;1", "nsIZipWriter");
   zipWriter.open(zippedFile, FileUtils.MODE_WRONLY | FileUtils.MODE_CREATE | FileUtils.MODE_TRUNCATE);
   zipWriter.addEntryFile("logfile.txt", zipWriter.COMPRESSION_BEST, fileToZip, false);
   zipWriter.close();
   return zippedFile;
}

这适用于服务器端(接收文件并写入新的压缩文件):

server = new WebSocketServer(12345);
server.onclient = function(client) {
   console.log(client + " connected");

   client.onmessage = function(client, msg) {
      client.send("Log Received");
      var zippedTmpFile = FileUtils.getFile("ProfD", ["report2.zip"], false);
      asyncTmpSave(zippedTmpFile, msg, onDone)

   };
};
server.connect();

function asyncTmpSave(file, data, callbackDone){
   var ostream = FileUtils.openFileOutputStream(file, FileUtils.MODE_WRONLY | FileUtils.MODE_CREATE | FileUtils.MODE_TRUNCATE);
   var converter = CCIN('@mozilla.org/intl/scriptableunicodeconverter', "nsIScriptableUnicodeConverter");
   converter.charset = 'UTF-8';
   var istream = converter.convertToInputStream(data);

   NetUtil.asyncCopy(istream, ostream, callbackSaved); 
      function callbackSaved (status) {     
         if(callbackDone){
           if(status===0)callbackDone( file.path, file.leafName, status);  //sucess.
           else callbackDone( null, null, status); //failure.
      }; 
  }
}
function onDone(path, leafName, statusCode){
   console.log([statusCode===0?"OK":"error",path,leafName].join("\n"));
}

我尝试传递字符串并且通信正常，在这种情况下，数据已传递并创建了文件，但 .zip 文件已损坏。你有什么想法？谢谢

Answer 1

你不能用 utf-8 编码随机的二进制内容。

WebSockets(和我的服务器)支持类型化数组。

所以你在发送需求时会:

var bytes = new Uint8Array(bstream.available());
bstream.readArrayBuffer(bytes.byteLength, bytes.buffer);
bstream.close();
ws.send(bytes);

在接收端您将收到 Uint8Array也是如此。