用 python 实现一个多线程网页下载器

很久没有更新博客了，今天上来分享一下昨天实现的一个多线程网页下载器。

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, httplibimport threadimport timefrom Queue import Queue, Empty, FullHEADERS = {"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 = -1POST = 'POST'GET = 'GET'def base_log(msg):print msgdef 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, timeoutexcept KeyError, e:log(str(e))continuelog('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 = HEADERStry: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)continueif response.status != httplib.OK:fail_op(task, response.status, log)continuedata = 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 Falsereturn Truedef get_results(self):results = []while True:try:res = self._results.get_nowait()except Empty:breakresults.append(res)return resultsdef 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, randomtask_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。