Question

我正在尝试使用JavaScript在我的Rails应用程序中创建一个简单的WebSocket连接。我得到以下内容：

与'ws：// localhost：4000 /'的WebSocket连接失败：WebSocket握手期间出错：'Sec-WebSocket-Accept'标头丢失

我做错了什么？这是我的代码：

JavaScript的：

var socket = new WebSocket('ws://localhost:4000');

socket.onopen = function() {
  var handshake =
    "GET / HTTP/1.1\n" +
    "Host: localhost\n" +
    "Upgrade: websocket\n" +
    "Connection: Upgrade\n" +
    "Sec-WebSocket-Key: x3JJHMbDL1EzLkh9GBhXDw==\n" +
    "Sec-WebSocket-Protocol: quote\n" +
    "Sec-WebSocket-Version: 13\n" +
    "Origin: http://localhost\n";

  socket.send(handshake);
};

socket.onmessage = function(data) {
  console.log(data);
};

红宝石：

require 'rubygems'
require 'em-websocket-server'

module QuoteService
  class WebSocket < EventMachine::WebSocket::Server
    def on_connect
      handshake_response =  "HTTP/1.1 101 Switching Protocols\n"
      handshake_response << "Upgrade: websocket\n"
      handshake_response << "Connection: Upgrade\n"
      handshake_response << "Sec-WebSocket-Accept: HSmrc0sMlYUkAGmm5OPpG2HaGWk=\n"
      handshake_response << "Sec-WebSocket-Protocol: quote\n"

      send_message(handshake_response)
    end

    def on_receive(data)
      puts 'RECEIVED: ' + data
    end
  end
end

EventMachine.run do
  print 'Starting WebSocket server...'
  EventMachine.start_server '0.0.0.0', 4000, QuoteService::WebSocket
  puts 'running'
end

握手标头符合Wikipedia。

Answer 1

1）我认为一旦连接打开，请求和响应已经发生，因此在此时发送标头为时已晚。此外，标题必须以空行结束，您省略了它。

2）根据演示，您甚至不必在客户端或服务器中设置标头 - ruby模块自动处理服务器端的标头，html5自动处理标头客户方。我认为这应该有效：

require "em-websocket-server"

class EchoServer < EM::WebSocket::Server

  def on_connect
    EM::WebSocket::Log.debug "Connected"
    puts "I felt a connection."
  end

  def on_receive msg
    puts "RECEIVED: #{msg}"
    send_message msg
  end

end

EM.run do
  myhost = "0.0.0.0"
  myport = 8000
  puts "Starting WebSocket server.  Listening on port #{myport}..."
  EM.start_server myhost, myport, EchoServer
end

html文件：

<!DOCTYPE html> <html> <head><title>Test</title>

<script type="text/javascript">

  var myWebSocket = new WebSocket("ws://localhost:8000");

  myWebSocket.onopen = function(evt)    { 
    console.log("Connection open. Sending message..."); 
    myWebSocket.send("Hello WebSockets!");       };

  myWebSocket.onmessage = function(evt)    { 
    console.log(evt.data);
    myWebSocket.close();   };

  myWebSocket.onclose = function(evt)    { 
    console.log("Connection closed.");    };

  myWebSocket.onerror = function(err)   {
    alert(err.name + " => " + err.message);   } </script>

</head> <body>   <div>Hello</div> </body> </html>

它在Safari 5.1.9（旧浏览器）中有效：我在服务器和客户端上看到了预期的输出。但是，代码在Firefox 21中不起作用：我收到错误消息...

Firefox can't establish a connection to the server at ws://localhost:8000/.
    var myWebSocket = new WebSocket("ws://localhost:8000");

我注意到在Firebug和Safari Developer Tools中，服务器都没有发送Sec-WebSocket-Accept标头：

Response Headers

Connection          Upgrade
Upgrade         WebSocket
WebSocket-Location  ws://localhost:8000/
WebSocket-Origin    null


Request Headers

Accept                  text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding         gzip, deflate
Accept-Language         en-US,en;q=0.5
Cache-Control           no-cache
Connection          keep-alive, Upgrade
DNT                 1
Host                    localhost:8000
Origin                  null
Pragma                  no-cache
Sec-WebSocket-Key   r9xT+ywe533EHF09wxelkg==
Sec-WebSocket-Version   13
Upgrade                 websocket
User-Agent          Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:21.0) Gecko/20100101 Firefox/21.0

我尝试的任何内容都不会使代码在Firefox 21.0中运行。为了检查Firefox 21.0是否支持websockets，我去了：

http://www.websocket.org/echo.html

它说我的浏览器确实支持websockets。

3）您是否有必要使用em-websocket-server模块？ github上该模块的最后一次修改是在三年前。每当你在ruby代码中看到require rubygems时，都会提醒你代码是旧的。我尝试了更新的em-websocket模块，并且我能够使用Firefox 21.0和Safari 5.1.9上的websockets成功地来回传输数据：

require 'em-websocket'

myhost = "0.0.0.0"
myport = 8000

EM.run {
  puts "Listening on port #{myport}..."

  EM::WebSocket.run(:host => myhost, :port => myport, :debug => false) do |ws|

    ws.onopen do |handshake|
      path = handshake.path
      query_str = handshake.query
      origin = handshake.origin

      puts "WebSocket opened:"
      puts "\t path  \t\t -> #{path}" 
      puts "\t query_str \t -> #{query_str}"
      puts "\t origin \t -> #{origin}"
    end 

    ws.onmessage { |msg|
      ws.send "Pong: #{msg}"
    }
    ws.onclose {
      puts "WebSocket closed"
    }
    ws.onerror { |e|
      puts "Error: #{e.message}"
    }
  end
}

相同的客户端代码。现在响应头包括Sec-WebSocket-Accept：

Response Headers

Connection          Upgrade
Sec-WebSocket-Accept    LyIm6d+kAAqkcTR744tVK9HMepY=
Upgrade                 websocket


Request Headers

Accept  text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding gzip, deflate
Accept-Language en-US,en;q=0.5
Cache-Control   no-cache
Connection  keep-alive, Upgrade
DNT 1
Host    localhost:8000
Origin  null
Pragma  no-cache
Sec-WebSocket-Key   pbK8lFHQAF+arl9tFvHn/Q==
Sec-WebSocket-Version   13
Upgrade websocket
User-Agent  Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:21.0) Gecko/20100101 Firefox/21.0

在您的代码中，我认为您没有设置任何标头。相反，您只是来回发送包含看起来像标题的字符的消息。显然，您的浏览器在允许连接之前需要响应中的Sec-WebSocket-Accept标头，并且当em-websocket-server模块未能在响应中设置该标头时，您的浏览器会拒绝连接。

em-websockets-server的相关源代码如下所示：

module EM
  module WebSocket
    module Protocol
      module Version76

        # generate protocol 76 compatible response headers
        def response
          response = "HTTP/1.1 101 Web Socket Protocol Handshake\r\n"
          response << "Upgrade: WebSocket\r\n"
          response << "Connection: Upgrade\r\n"
          response << "Sec-WebSocket-Origin: #{origin}\r\n"
          response << "Sec-WebSocket-Location: #{scheme}://#{host}#{path}\r\n"

          if protocol
            response << "Sec-WebSocket-Protocol: #{protocol}\r\n"
          end

          response << "\r\n"
          response << Digest::MD5.digest(keyset)

          response
        end

如您所见，它没有设置Sec-WebSocket-Accept标头。该代码位于名为Version76的模块中，并且搜索google for websockets版本76会产生一个过时的协议（其中包含请求和响应的示例）：

http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol-76

这是当前的websockets协议（其中还包含请求和响应的示例）：

http://tools.ietf.org/html/rfc6455

结论： em-websockets-server已过时。

与Ruby和EM :: WebSocket :: Server的WebSocket握手

1 个答案: