python实现多线程网页下载器

本文为大家分享了python实现的一个多线程网页下载器，供大家参考，具体内容如下

这是一个有着真实需求的实现，我的用途是拿它来通过 HTTP 方式向服务器提交游戏数据。把它放上来也是想大家帮忙挑刺，找找 bug，让它工作得更好。

keywords:python,http,multi-threads,thread,threading,httplib,urllib,urllib2,Queue,http pool,httppool

废话少说，上源码：

# -*- coding:utf-8 -*-
import urllib, httplib
import thread
import time
from Queue import Queue, Empty, Full
HEADERS = {"Content-type": "application/x-www-form-urlencoded",
            'Accept-Language':'zh-cn',
            'User-Agent': 'Mozilla/4.0 (compatible; MSIE 6.0;Windows NT 5.0)',
            "Accept": "text/plain"}
UNEXPECTED_ERROR = -1
POST = 'POST'
GET = 'GET'
def base_log(msg):
  print msg
def base_fail_op(task, status, log):
  log('fail op. task = %s, status = %d'%(str(task), status))
def get_remote_data(tasks, results, fail_op = base_fail_op, log = base_log):
  while True:
    task = tasks.get()
    try:
      tid = task['id']
      hpt = task['conn_args'] # hpt <= host:port, timeout
    except KeyError, e:
      log(str(e))
      continue
    log('thread_%s doing task %d'%(thread.get_ident(), tid))
    #log('hpt = ' + str(hpt))
    conn = httplib.HTTPConnection(**hpt) 

    try:
      params = task['params']
    except KeyError, e:
      params = {}
    params = urllib.urlencode(params)
    #log('params = ' + params) 

    try:
      method = task['method']
    except KeyError:
      method = 'GET'
    #log('method = ' + method) 

    try:
      url = task['url']
    except KeyError:
      url = '/'
    #log('url = ' + url) 

    headers = HEADERS
    try:
      tmp = task['headers']
    except KeyError, e:
      tmp = {}
    headers.update(tmp)
    #log('headers = ' + str(headers))
    headers['Content-Length'] = len(params) 

    try:
      if method == POST:
        conn.request(method, url, params, headers)
      else:
        conn.request(method, url + params)
      response = conn.getresponse()
    except Exception, e:
      log('request failed. method = %s, url = %s, params = %s headers = %s'%(
            method, url, params, headers))
      log(str(e))
      fail_op(task, UNEXPECTED_ERROR, log)
      continue 

    if response.status != httplib.OK:
      fail_op(task, response.status, log)
      continue 

    data = response.read()
    results.put((tid, data), True) 

class HttpPool(object):
  def __init__(self, threads_count, fail_op, log):
    self._tasks = Queue()
    self._results = Queue() 

    for i in xrange(threads_count):
      thread.start_new_thread(get_remote_data,
                              (self._tasks, self._results, fail_op, log)) 

  def add_task(self, tid, host, url, params, headers = {}, method = 'GET', timeout = None):
    task = {
      'id' : tid,
      'conn_args' : {'host' : host} if timeout is None else {'host' : host, 'timeout' : timeout},
      'headers' : headers,
      'url' : url,
      'params' : params,
      'method' : method,
      }
    try:
      self._tasks.put_nowait(task)
    except Full:
      return False
    return True 

  def get_results(self):
    results = []
    while True:
      try:
        res = self._results.get_nowait()
      except Empty:
        break
      results.append(res)
    return results 

def test_google(task_count, threads_count):
  hp = HttpPool(threads_count, base_fail_op, base_log)
  for i in xrange(task_count):
    if hp.add_task(i,
        'www.google.cn',
        '/search?',
        {'q' : 'lai'},
#        method = 'POST'
        ):
      print 'add task successed.' 

  while True:
    results = hp.get_results()
    if not results:
      time.sleep(1.0 * random.random())
    for i in results:
      print i[0], len(i[1])
#      print unicode(i[1], 'gb18030') 

if __name__ == '__main__':
  import sys, random
  task_count, threads_count = int(sys.argv[1]), int(sys.argv[2])
  test_google(task_count, threads_count)

有兴趣想尝试运行的朋友，可以把它保存为 xxxx.py，然后执行 python xxxx.py 10 4，其中 10 表示向 google.cn 请求 10 次查询，4 表示由 4 条线程来执行这些任务。

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