使用 javascript 通过 websockets 传输文件
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transferring files with javascript through websockets
提问by DasBoot
hello i am trying to transfer files. I have some programs converting files to binary and transferring them over a network with c++. I was wondering if i would be able to transfer files with javascripts and websockets? any examples on how to integrate my c++ program into javascript would be appreciated. thanks.
您好，我正在尝试传输文件。我有一些程序将文件转换为二进制文件并使用 C++ 通过网络传输它们。我想知道我是否可以使用 javascripts 和 websockets 传输文件？任何关于如何将我的 C++ 程序集成到 javascript 的示例将不胜感激。谢谢。
回答by kanaka
Javascript has two new binary types: typed arrays (arraybuffers) and Blobs (basically files).
Javascript 有两种新的二进制类型：类型数组（arraybuffers）和 Blob（基本上是文件）。
WebSockets support sending and receiving typed arrays and blobs.
WebSockets 支持发送和接收类型化数组和 blob。
To transfer data between two browsers using WebSockets you will need a server for them both to connect to (browser WebSocket support is client only at this point).
要使用 WebSockets 在两个浏览器之间传输数据，您需要一个服务器来连接它们（此时浏览器 WebSocket 支持仅是客户端）。
If you have an existing server in C++ that handles file transport then you should be able to add WebSocket server support to it fairly easily. You can find WebSocket client and server implementations on this page: http://en.wikipedia.org/wiki/Comparison_of_WebSocket_implementations
如果你有一个现有的 C++ 服务器来处理文件传输，那么你应该能够很容易地向它添加 WebSocket 服务器支持。您可以在此页面上找到 WebSocket 客户端和服务器实现：http: //en.wikipedia.org/wiki/Comparison_of_WebSocket_implementations
In JavaScript to establish a connection to a WebSocket server you do something like this:
在 JavaScript 中，要建立到 WebSocket 服务器的连接，您可以执行以下操作：
ws = new WebSocket("ws://100.101.102.103");
The send() method support normal strings, typed arrays or blobs. Sending typed arrays and blobs will result in the frame(s) received by the server as binary frames (opcode = 2).
send() 方法支持普通字符串、类型化数组或 blob。发送类型化数组和 blob 将导致服务器作为二进制帧（操作码 = 2）接收的帧。
ws.send(myTypedArray);
To receive messages you register a message handler:
要接收消息，请注册消息处理程序：
ws.onmessage = function (evt) {
console.log("Got ws message: " + evt.data);
};
If the server sends a binary frame/message then the onmessage data property of the event will contain either a typed array or blob depending on the setting of the binaryType attribute. You can change the type of the binary data that is received like this:
如果服务器发送二进制帧/消息，则事件的 onmessage 数据属性将包含类型化数组或 blob，具体取决于 binaryType 属性的设置。您可以像这样更改接收到的二进制数据的类型：
ws.binaryType = "blob"; // or "arraybuffer"
回答by duskwuff -inactive-
What you're trying to do isn't possible. WebSocket can only operate in a client mode; it cannot accept connections from another WebSocket client (such as another browser).
你试图做的事情是不可能的。WebSocket 只能在客户端模式下运行；它不能接受来自另一个 WebSocket 客户端（例如另一个浏览器）的连接。
It is possible to hook WebSocket clients to one another through a server, but at that point it's no longer really peer-to-peer, so I'm not sure if that's really useful or interesting anymore.
可以通过服务器将 WebSocket 客户端相互挂钩，但那时它不再是真正的点对点，所以我不确定这是否真的有用或有趣了。
