Question

这是我在Python下第一次接触ZMQ，我希望服务器在收到客户端的请求时发送多行。我添加到ZMQ在服务器端提供的示例中的代码是：

with open("test.txt", 'r') as f:
    for line in f:
        socket.send_string(line.rstrip("\n"))

问题是如何使服务器发送所有行或如何使客户端不在服务器之前发送请求完成从test.txt

发送所有行

客户端

import zmq
context = zmq.Context()
print("Connecting to hello world server")
socket = context.socket(zmq.REQ)
socket.connect("tcp://localhost:5555")
for request in range(10):
    print("Sending request %s" % request)
    socket.send(b"Hello")
    message = socket.recv()
    print("Received reply %s [ %s ]" % (request, message))

服务器

import time
import zmq

context = zmq.Context()
socket = context.socket(zmq.REP)
socket.bind("tcp://*:5555")

while True:
    #  Wait for next request from client
    message = socket.recv()
    print("Received request: %s" % message)

    #  Do some 'work'
    time.sleep(1)

    #  Send reply back to client
    with open("test.txt", 'r') as f:
        for line in f:
            socket.send_string(line.rstrip("\n"))

客户端日志

Connecting to hello wolrd server
Sending request 0
Received reply 0 [ This is test line 1 ]
Sending request 1

这是它停止的地方，因为服务器生成了下面显示的错误：

服务器日志

line 324, in send_string
     return self.send(u.encode(encoding), flags=flags, copy=copy)
File "socket.pyx", line 571, in zmq.backend.cython.socket.Socket.send (zmq/backend/cython/socket.c:5319)
File "socket.pyx", line 618, in zmq.backend.cython.socket.Socket.send (zmq/backend/cython/socket.c:5086)
File "socket.pyx", line 181, in zmq.backend.cython.socket._send_copy (zmq/backend/cython/socket.c:2081)
File "checkrc.pxd", line 21, in zmq.backend.cython.checkrc._check_rc (zmq/backend/cython/socket.c:6032)
zmq.error.ZMQError: Operation cannot be accomplished in current state

Process finished with exit code 1

的test.txt

This is test line 1
This is test line 2
This is test line 3
This is test line 4
This is test line 5

Answer 1

以下是我提出的解决方案......以防万一有人可能需要类似情况的帮助。我们的想法是将所有行打包在一条消息中并将其发送回客户端。似乎它的工作原理是，对于客户端发出的每个请求，服务器都需要做出回复并且只需要一个回复。至少我就是这样看的..

替换服务器端的代码

#  Send reply back to client
with open("test.txt", 'r') as f:
    for line in f:
        socket.send_string(line.rstrip("\n"))

使用：

#  Send reply back to client
with open("test.txt", 'r') as f:
    message = '%s' % f.readlines()
    print(message)
    print(type(message))
    socket.send_string(message)

客户请求

Connecting to hello world server
Sending request 0
Received reply 0 [ ['This is test line 1\n', 'This is test line 2\n', 'This is test line 3\n', 'This is test line 4\n', 'This is test line 5\n', 'This is test line 6\n', 'This is test line 7\n', 'This is test line 8\n', 'This is test line 9\n', 'This is test line 10\n', '\n'] ]
Sending request 1
Received reply 1 [ ['This is test line 1\n', 'This is test line 2\n', 'This is test line 3\n', 'This is test line 4\n', 'This is test line 5\n', 'This is test line 6\n', 'This is test line 7\n', 'This is test line 8\n', 'This is test line 9\n', 'This is test line 10\n', '\n'] ]
 ....
 ....
 and so on up to 10 requests

服务器响应

Received request: Hello
['This is test line 1\n', 'This is test line 2\n', 'This is test line 3\n', 'This is test line 4\n', 'This is test line 5\n', 'This is test line 6\n', 'This is test line 7\n', 'This is test line 8\n', 'This is test line 9\n', 'This is test line 10\n', '\n']
<type 'str'>
Received request: Hello
['This is test line 1\n', 'This is test line 2\n', 'This is test line 3\n', 'This is test line 4\n', 'This is test line 5\n', 'This is test line 6\n', 'This is test line 7\n', 'This is test line 8\n', 'This is test line 9\n', 'This is test line 10\n', '\n']
<type 'str'>
....
....
....
and so on....

现在这已经解决了，接下来的问题是：客户端需要发送什么样的请求才能以逐行方式接受来自服务器的响应。如果我有解决方案，我会更新回复，或者您可以随意参与。

Answer 2

好吧，你想出了我的首选解决方案，就是将整个事件作为单个消息发送，必要时使用单独的帧。也就是说，它允许您只发送一个回复的原因是因为您正在使用REQ-REP套接字对，并且当使用这样的一对时，您必须遵循一个简单的“请求 - 回复请求回复“模式。每个通信必须以一个请求开始，下一个消息必须是一个回复，下一个请求等等。

要解决此问题，您有以下几种选择：

正如您所做的那样，将您要发送的所有内容打包在一条消息中。在你的情况下，只要没有阻止它的约束，这将是首选选项，因为所有数据实际上是一个逻辑消息，来自一个逻辑文件，并且它将全部组成一个逻辑块接收端的数据，我认为。
如果您想保留REQ-REP套接字对，那么您可以发送请求，然后回复，然后您的下一个请求可以是“更多”或类似的东西，然后是下一个数据，并继续请求“更多”，直到您的客户回复“DONE”之类的内容，此时您知道您拥有所有数据并且可以退出请求更多数据。
或者，如果您希望能够对单个请求做多个回复，或者在收到回复之前多次请求，那么您将需要使用ROUTER-DEALER套接字对而不是{{1} }。在这种情况下，您的REQ-REP套接字将取代DEALER套接字，REQ代替ROUTER。如果您遇到如何实施REP。

Python中的简单客户端/服务器ZMQ，每个请求发送多行

客户端

服务器

客户端日志

服务器日志

的test.txt

2 个答案:

客户请求

服务器响应