QThreads和xmlrpc clien

Question

我尝试从许多qthread使用xmlrpc客户机。为了确保只有一个线程使用xmlrpc客户机，我用QMutex创建了锁。我的代码：

import sys
import xmlrpclib
import threading
import time

from SimpleXMLRPCServer import SimpleXMLRPCServer

from PyQt4 import QtCore, QtGui

class MM(object):
    def __init__(self):
        self.lock = QtCore.QMutex()
        self.xmlrpc_client = xmlrpclib.ServerProxy('http://localhost:9092')

    def __getattr__(self, name):
        self.lock.lock()
        sys.stderr.write('locked, for %s\n' % name)
        print threading.current_thread()
        result = self.xmlrpc_client.__getattr__(name)
        sys.stderr.write('unlocked by %s\n' % name)
        self.lock.unlock()
        return result

class Server(QtCore.QThread):
    def __init__(self):
        QtCore.QThread.__init__(self)
        self.server = None

    def run(self):
        self.server = SimpleXMLRPCServer(("localhost", 9092), logRequests = False)
        def one():
            return 1
        self.server.register_function(one, 'one')
        self.server.serve_forever()
        print "SERVER DONE"


class Ask(QtCore.QThread):
    def __init__(self, mmInst):
        QtCore.QThread.__init__(self)
        self.mm = mmInst
        self._stopping = False

    def run(self):
        while not self._stopping:
            time.sleep(0.5)
            print self.mm.one()

    def stop(self):
        self._stopping = True
        self.wait()


def start_gui():
    app = QtGui.QApplication(sys.argv)

    server = Server()
    server.start()

    time.sleep(1)

    mm = MM()
    print mm.one()

    a1 = Ask(mm)
    a1.start()

    a2 = Ask(mm)
    a2.start()

    try:
        app.exec_()
    except keyboardInterrupt:
        server.server.shutdown()

if __name__ == "__main__":
    start_gui()

但它不起作用，我也不知道为什么。输出如下：

^{pr2}$

当只使用一根线时：

$ diff -u test.py.back test.py
--- test.py.back        2012-03-14 01:34:37.666425000 +0100
+++ test.py     2012-03-14 01:33:01.423265000 +0100
@@ -63,8 +63,8 @@
     a1 = Ask(mm)
     a1.start()

-    a2 = Ask(mm)
-    a2.start()
+    #a2 = Ask(mm)
+    #a2.start()

     try:
         app.exec_()
$ python test.py
locked, for one
<_MainThread(MainThread, started -1219930432)>
unlocked by one
1
locked, for one
<_DummyThread(Dummy-1, started daemon -1287918736)>
unlocked by one
1
locked, for one
<_DummyThread(Dummy-1, started daemon -1287918736)>
unlocked by one
1
locked, for one
<_DummyThread(Dummy-1, started daemon -1287918736)>
unlocked by one
1

当使用两个不同的MM实例时，也可以正常工作：

$ diff -u test.py.back test.py
--- test.py.back        2012-03-14 01:34:37.666425000 +0100
+++ test.py     2012-03-14 01:38:47.352862000 +0100
@@ -57,13 +57,13 @@

     time.sleep(1)

-    mm = MM()
-    print mm.one()
+    #mm = MM()
+    #print mm.one()

-    a1 = Ask(mm)
+    a1 = Ask(MM())
     a1.start()

-    a2 = Ask(mm)
+    a2 = Ask(MM())
     a2.start()

     try:
adam@sabayon /media/Nowy/poker/repos/TestSuite $ python test.py
locked, for one
locked, for one
<_DummyThread(Dummy-1, started daemon -1288275088)><_DummyThread(Dummy-2, started daemon -1298138256)>
unlocked by one

unlocked by one
11

locked, for one
<_DummyThread(Dummy-2, started daemon -1298138256)>
unlocked by one
locked, for one
<_DummyThread(Dummy-1, started daemon -1288275088)>
unlocked by one
1
1
locked, for one
<_DummyThread(Dummy-1, started daemon -1288275088)>
unlocked by one
locked, for one
1<_DummyThread(Dummy-2, started daemon -1298138256)>

unlocked by one
1

Answer 1

我在代码中看到了几个问题，但我马上就要解决的一个问题是，在服务器准备好之前启动客户机。当我先实例化服务器，然后实例化客户机时，我停止了获取连接错误。在

我还删除了spinning while循环，而只是启动了pyqt事件循环。另外，您并没有真正地将MM实例传递给Ask类（对于本例来说，这并不重要，因为您使用的是同一个实例）。在

不管怎么说，下面是我的版本，它似乎起作用了：

import sys
import xmlrpclib
import threading
import time

from SimpleXMLRPCServer import SimpleXMLRPCServer

from PyQt4 import QtCore, QtGui

class MM(object):
    def __init__(self):
        self.lock = QtCore.QMutex()
        self.xmlrpc_client = xmlrpclib.ServerProxy('http://localhost:9092')

    def __getattr__(self, name):
        self.lock.lock()
        sys.stderr.write('locked, for %s\n' % name)
        print threading.current_thread()
        result = self.xmlrpc_client.__getattr__(name)
        sys.stderr.write('unlocked by %s\n' % name)
        self.lock.unlock()
        return result

class Server(QtCore.QThread):
    def __init__(self):
        QtCore.QThread.__init__(self)
        self.server = None

    def run(self):
        self.server = SimpleXMLRPCServer(("localhost", 9092), logRequests = False)
        def one():
            return 1
        self.server.register_function(one, 'one')
        self.server.serve_forever()
        print "SERVER DONE"


class Ask(QtCore.QThread):
    def __init__(self, mmInst):
        QtCore.QThread.__init__(self)
        self.mm = mmInst
        self._stopping = False

    def run(self):
        while not self._stopping:
            time.sleep(0.5)
            print self.mm.one()

    def stop(self):
        self._stopping = True
        self.wait()


def start_gui():
    app = QtGui.QApplication(sys.argv)

    server = Server()
    server.start()

    time.sleep(.25)

    mm = MM()
    print mm.one()

    a1 = Ask(mm)
    a1.start()

    a2 = Ask(mm)
    a2.start()

    try:
        app.exec_()
    except KeyboardInterrupt:
        server.server.shutdown()


if __name__ == "__main__":
    start_gui()

更新

在仔细研究了一下之后，我发现这是Python2.7和xmlrpc中的一个bug，它们改变了它创建连接的方式。http://bugs.python.org/issue6907

奇怪的是，这段代码在OSX上的Python2.6/2.7或linux下的Python2.6上不会崩溃。但是对于我来说，在linux下使用Python2.7确实会崩溃。在

当我将锁定机制移到MM实例之外时，它似乎开始在linux上的2.7下工作：

^{pr2}$