Python - 我怎样才能让客户端能够连接多次？

Question

只有当我使用 client1 = HTTPClient('192.168.1.2', '3') 时它才有效，但当我同时使用以下两种时： client1 = HTTPClient('192.168.1.2', '3') client2 = HTTPClient('192.168.1.3', '3')

然后整个事情变得非常缓慢，有时其中一个会失败。如何确保client1和client2连接+发送+足够快？

import asyncore, socket

class HTTPClient(asyncore.dispatcher):

  def __init__(self, host, path):
    asyncore.dispatcher.__init__(self)
    self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
    self.settimeout(10)
    try:
      self.connect( (host, 8888) )
    except:
      print 'unable to connect'
      pass
    self.buffer = path

  def handle_connect(self):
    pass

  def handle_close(self):
    self.close()

  def handle_read(self):
    print self.recv(8192)

  def writable(self):
    return (len(self.buffer) > 0)

  def handle_write(self):
    sent = self.send(self.buffer)
    self.buffer = self.buffer[sent:]


client1 = HTTPClient('192.168.1.2', '3')
client2 = HTTPClient('192.168.1.3', '3')
asyncore.loop()

编辑：也尝试了线程，但结果相同

import asyncore, socket
import threading
import os

class HTTPClient(asyncore.dispatcher):

  def __init__(self, host, path):
    asyncore.dispatcher.__init__(self)
    self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
    self.settimeout(10)
    try:
      self.connect( (host, 8888) )
    except:
      print 'unable to connect'
      pass
    self.buffer = path

  def handle_connect(self):
    pass

  def handle_close(self):
    self.close()

  def handle_read(self):
    print self.recv(8192)

  def writable(self):
    return (len(self.buffer) > 0)

  def handle_write(self):
    sent = self.send(self.buffer)
    self.buffer = self.buffer[sent:]

def t1():
  client1 = HTTPClient('192.168.1.161', '3')  

def t2():
  client2 = HTTPClient('192.168.1.163', '3')

t0 = threading.Thread(target=t1())
t0.start()
t0.join() 

t0 = threading.Thread(target=t2())
t0.start()
t0.join() 

asyncore.loop()

Answer 1

您的 HTTPClient 的连接方法正在阻塞，如果您的第二个主机不排除连接，则您的 try/except 块在超时后会令人兴奋。您的 except 块没有关闭套接字，因此 acyncore.loop() 仍在等待它。

在下面尝试我的修改，看看他们是否确认了问题。我在 connect 方法周围放置了一些打印语句来说明代码的阻塞部分，并且我已经明确地关闭了异常中的套接字。如果您可以发布服务器代码也会很有帮助，因为我预计问题就在那里。如果服务器代码不在您的控制范围内，您的代码会将您的时间缩短到更小，并打开某种循环的连接，但您应该在每次迭代时退出连接尝试（等待 1 秒，然后 2 秒，然后 4 秒，然后 8 秒，等连接尝试之间）。

import asyncore, socket
import time

class HTTPClient(asyncore.dispatcher):

  def __init__(self, host, path):
    asyncore.dispatcher.__init__(self)
    self.HOST = host
    self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
    self.settimeout(10)
    try:
      t0 = time.time()
      print "connecting to host:", host, '...blocking...'
      self.connect( (host, 80) )
      print "connected to host (%s) in %0.2f seconds:"%(host, time.time()-t0)
    except:
      print 'unable to connect'
      self.close()
    self.buffer = path

  def handle_connect(self):
    pass

  def handle_close(self):
    self.close()

  def handle_read(self):
    print self.recv(8192)

  def writable(self):
    return (len(self.buffer) > 0)

  def handle_write(self):
    sent = self.send(self.buffer)
    self.buffer = self.buffer[sent:]


client1 = HTTPClient('news.google.com', 'GET / HTTP/1.0\r\n\r\n')
client2 = HTTPClient('not_a_valid_server.local', 'GET / HTTP/1.0\r\n\r\n')
client3 = HTTPClient('news.yahoo.com', 'GET / HTTP/1.0\r\n\r\n')
asyncore.loop()

Answer 2

您的代码中可能存在多个问题，例如，在指定目标时删除括号：Thread(target=t1)。如果f 是一个函数，那么f() 会立即调用它。您还将asyncore 与阻塞代码和多线程混合在一起。

如果你想同时建立几个http连接；您可以改用线程池：

import urllib2
from multiprocessing.dummy import Pool # use threads

def fetch(url):
    try:
        return url, urllib2.urlopen(url).read(), None
    except Exception as e:
        return url, None, str(e)

urls = ['http://example.com', ...]
pool = Pool(20) # use no more than 20 concurrent connections
for url, result, error in pool.imap_unordered(fetch, urls):
    if error is None:
       print(url + " done")
    else:
       print(url + " error: " + error)