通过LISP USOCKET接收数据

Question

我正在尝试通过USOCKET发送数据.当数据到达服务器时,服务器应该回复.但是,stream-read(如下定义)仅在数据与其发送的原始数据一起回显时返回数据.例如,如果我发送hello并且服务器回复相同的数据,hello则stream-read返回,但如果服务器回复hi,stream-read则在服务器发送它收到的确切缓冲区之前不会返回.

这是代码:(我在网上找到了大部分代码.)

;; Load USocket
(load #P"/usr/share/common-lisp/source/cl-asdf/asdf.lisp")      
(asdf:operate 'asdf:load-op :usocket)

(defun stream-read (stream)
  (socket-listen (usocket:socket-stream stream)))

(defun stream-print (string stream)
  (write-line string (usocket:socket-stream stream))
  (force-output (usocket:socket-stream stream)))

;; Define a stream
(defparameter my-stream
  (usocket:socket-connect "127.0.0.1" 6003))

;; Use the stream
(stream-print "random" my-stream)
(print (stream-read my-stream))

至于服务器,我使用了一个略微修改版本的boost阻塞服务器示例.(c ++)完整的代码可以在这里找到:http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/example/echo/blocking_tcp_echo_server.cpp

...

void session(socket_ptr sock)
{
   try
   {    
    for (;;)
    {
      char data[max_length];

      boost::system::error_code error;
      size_t length = sock->read_some(boost::asio::buffer(data), error);
      if (error == boost::asio::error::eof)
      break; // Connection closed cleanly by peer.
      else if (error)
      throw boost::system::system_error(error); // Some other error.


    std::vector<char> v(data,data+length);
            std::string theStr;

        for(unsigned int i=0;i<v.size();i++)
        {
        if(v[i]<32 || v[i]>=0x7f);//Remove non-ascii char
        else theStr.insert(theStr.end(),v[i]);
    }
    std::cout<<"|"<<theStr<<"|"<<std::endl;

    boost::asio::write(*sock, boost::asio::buffer(data, length)); //works
    boost::asio::write(*sock, boost::asio::buffer("some", 4));  //doesn't work
}
  }
  catch (std::exception& e)
  {
    std::cerr << "Exception in thread: " << e.what() << "\n";
  }
}
   ...

Answer 1

如果没有看到服务器的代码,如果没有一点猜测就很难回答.但:

1. 从客户端到服务器的每次调用都使用相同的套接字.如果服务器不期望它,它将不会按照您的意愿运行.

2. 你的stream-read电话定义socket-listen.你的意思是usocket:socket-listen？这是一个服务器端函数(并采用不同的参数).我可能不会查看您运行的确切代码.

3. 咨询说明:(a)my-stream实际上是一个套接字,而不是一个流; (b)我鼓励您使用Quicklisp管理外部库.

这是一个完整的工作示例.这是在LispWorks上; 我已经使用LW内部服务器使服务器完全清楚哪个是服务器,哪个是客户端.

CL-USER 1 > (ql:quickload :usocket)
To load "usocket":
  Load 1 ASDF system:
    usocket
; Loading "usocket"

(:USOCKET)

CL-USER 2 > (comm:start-up-server
             :service 6003
             :function (lambda (handle)
                         (let* ((stream (make-instance 'comm:socket-stream
                                                       :socket handle
                                                       :direction :io
                                                       :element-type 'base-char))
                                (line (read-line stream)))
                           (format stream "Hello: ~a~%" line)
                           (force-output stream))))
#<MP:PROCESS Name "6003 server" Priority 85000000 State "Running">

CL-USER 3 > (defun socket-read (socket)
              (read-line (usocket:socket-stream socket)))
SOCKET-READ

CL-USER 4 > (defun socket-print (string socket)
              (write-line string (usocket:socket-stream socket))
              (force-output (usocket:socket-stream socket)))
SOCKET-PRINT

CL-USER 5 > (defun test (thing)
              (let ((socket (usocket:socket-connect "127.0.0.1" 6003)))
                (socket-print thing socket)
                (socket-read socket)))
TEST

CL-USER 6 > (test "Buttered toast")
"Hello: Buttered toast"
NIL

CL-USER 7 > (test "A nice cup of tea")
"Hello: A nice cup of tea"
NIL

如果您仍然遇到困难,请再次使用您的服务器和实际的源代码发布stream-read.