python爬蟲之Scrapy 使用代理配置

在爬取網站內容的時候，最常遇到的問題是：網站對IP有限制，會有防抓取功能，最好的辦法就是IP輪換抓取（加代理）

下面來說一下Scrapy如何配置代理，進行抓取

1.在Scrapy工程下建立“middlewares.py”

# Importing base64 library because we'll need it ONLY in case if the proxy we are going to use requires authenticationimport base64 # Start your middleware classclass ProxyMiddleware(object):    # overwrite process request    def process_request(self, request, spider):        # Set the location of the proxy        request.meta['proxy'] = "http://YOUR_PROXY_IP:PORT"          # Use the following lines if your proxy requires authentication        proxy_user_pass = "USERNAME:PASSWORD"        # setup basic authentication for the proxy        encoded_user_pass = base64.encodestring(proxy_user_pass)        request.headers['Proxy-Authorization'] = 'Basic ' + encoded_user_pass

2.在項目設定檔裡(./pythontab/settings.py)添加

DOWNLOADER_MIDDLEWARES = {    'scrapy.contrib.downloadermiddleware.httpproxy.HttpProxyMiddleware': 110,    'pythontab.middlewares.ProxyMiddleware': 100,}

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