common.py 文件源码

def download5(url, user_agent='wswp', proxy=None, num_retries=2):
    """Download function with support for proxies"""
    print 'Downloading:', url
    headers = {'User-agent': user_agent}
    request = urllib2.Request(url, headers=headers)
    opener = urllib2.build_opener()
    if proxy:
        proxy_params = {urlparse.urlparse(url).scheme: proxy}
        opener.add_handler(urllib2.ProxyHandler(proxy_params))
    try:
        html = opener.open(request).read()
    except urllib2.URLError as e:
        print 'Download error:', e.reason
        html = None
        if num_retries > 0:
            if hasattr(e, 'code') and 500 <= e.code < 600:
                # retry 5XX HTTP errors
                html = download5(url, user_agent, proxy, num_retries-1)
    return html