与Ruby和EM :: WebSocket :: Server的WebSocket握手 [英] WebSocket handshake with Ruby and EM::WebSocket::Server
问题描述
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：
I am trying to create a simple WebSocket connection in JavaScript against my Rails app. I get the following:
与'ws：// localhost：4000 /'的WebSocket连接失败：WebSocket握手期间出错：'缺少WebSocket-Accept'标题
WebSocket connection to 'ws://localhost:4000/' failed: Error during WebSocket handshake: 'Sec-WebSocket-Accept' header is missing
我做错了什么？这是我的代码：
What am I doing wrong? Here is my code:
JavaScript：
JavaScript:
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);
};
Ruby：
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
握手标题符合维基百科。
推荐答案
1）我认为一旦连接打开，请求和响应已经发生，所以在那时发送标题为时已晚。此外，标题必须以空白行结束，您省略。
1) I think that once the connection is open the request and response have already occurred, so sending headers at that point is too late. In addition, headers have to end with a blank line, which you omitted.
2）根据演示，您甚至不必在客户端设置标题或服务器 - ruby模块自动处理服务器端的标头，html5自动处理客户端的标头。我认为这应该有效：
2) According to the demos, you don't even have to set headers in the client or the server--the ruby module automatically takes care of the headers on the server side, and html5 automatically takes care of the headers on the client side. I think this should work:
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：我看到了预期服务器和客户端上的输出。但是，代码在Firefox 21中不起作用：我收到错误消息...
And it does work in Safari 5.1.9 (which is an older browser): I see the expected output on both the server and the client. However, the code does not work in Firefox 21: I get the error message...
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-接受标题：
I notice that in both Firebug and Safari Developer Tools, the server does not send a Sec-WebSocket-Accept header:
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：
Nothing I tried would make the code work in Firefox 21.0. To check whether Firefox 21.0 even supports websockets, I went to:
http://www.websocket.org/echo.html
它说我的浏览器支持websockets。
and it said my browser does support 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，就会提醒你代码是旧的。我尝试了新的em-websocket模块，我能够使用Firefox 21.0和Safari 5.1.9上的websockets来回成功传输数据：
3) Is there any reason you have to use the em-websocket-server module? The last modification for that module on github was three years ago. And whenever you see require rubygems in ruby code, that should alert you that the code is old. I tried the newer em-websocket module, and I was able to successfully transfer data back and forth using websockets on both Firefox 21.0 and Safari 5.1.9:
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。现在响应标头包括Sec-WebSocket-Accept：
Same client side code. Now the response headers include 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题。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。
In your code, I don't think you are setting any headers. Instead, you are just sending messages back and forth that happen to contain characters that look like headers. Apparently, your browser requires the Sec-WebSocket-Accept header in the response before it will allow the connection, and when the em-websocket-server module fails to set that header in the response, your browser refuses the connection.
em-websockets-server的相关源代码如下所示：
The relevant source code for em-websockets-server looks like this:
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）：
As you can see, it doesn't set the Sec-WebSocket-Accept header. That code is in a module called Version76, and searching google for websockets version 76 yields an obsolete protocol(which contains an example of a request and response):
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）：
Here is the current websockets protocol(which also contains an example of a request and response):
http://tools.ietf.org/html/rfc6455
结论： em-websockets-server已过时。
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