根据scrapy官方文档：
http://doc.scrapy.org/en/master/topics/practices.html#avoiding-getting-banned
里面的描述，要防止scrapy被ban，主要有以下几个策略。
1，动态设置user agent
2，禁用cookies
3，设置延迟下载
4，使用Google cache
5，使用IP地址池（Tor project、VPN和代理IP）
6，使用Crawlera
由于Google cache受国内网络的影响，你懂得；
Crawlera的分布式下载，我们可以在下次用一篇专门的文章进行讲解。
所以本文主要从动态随机设置User-Agent、禁用cookies、设置延迟下载和使用代理IP这几个方式。
首先设置一下setttings
USER_AGENTS = [
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; AcooBrowser; .NET CLR 1.1.4322; .NET CLR 2.0.50727)",
"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; Acoo Browser; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.0.04506)",
"Mozilla/4.0 (compatible; MSIE 7.0; AOL 9.5; AOLBuild 4337.35; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)",
"Mozilla/5.0 (Windows; U; MSIE 9.0; Windows NT 9.0; en-US)",
"Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET CLR 2.0.50727; Media Center PC 6.0)",
"Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET CLR 1.0.3705; .NET CLR 1.1.4322)",
"Mozilla/4.0 (compatible; MSIE 7.0b; Windows NT 5.2; .NET CLR 1.1.4322; .NET CLR 2.0.50727; InfoPath.2; .NET CLR 3.0.04506.30)",
"Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN) AppleWebKit/523.15 (KHTML, like Gecko, Safari/419.3) Arora/0.3 (Change: 287 c9dfb30)",
"Mozilla/5.0 (X11; U; Linux; en-US) AppleWebKit/527+ (KHTML, like Gecko, Safari/419.3) Arora/0.6",
"Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.2pre) Gecko/20070215 K-Ninja/2.1.1",
"Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9) Gecko/20080705 Firefox/3.0 Kapiko/3.0",
"Mozilla/5.0 (X11; Linux i686; U;) Gecko/20070322 Kazehakase/0.4.5",
"Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.8) Gecko Fedora/1.9.0.8-1.fc10 Kazehakase/0.5.6",
"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11",
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_3) AppleWebKit/535.20 (KHTML, like Gecko) Chrome/19.0.1036.7 Safari/535.20",
"Opera/9.80 (Macintosh; Intel Mac OS X 10.6.8; U; fr) Presto/2.9.168 Version/11.52",
]
DOWNLOADER_MIDDLEWARES = {
'weibo.middlewares.RandomUserAgent': 1,
'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware': 110,
'weibo.middlewares.ProxyMiddleware': 100
}
COOKIES_ENABLED = False
DOWNLOADER_MIDDLEWARES = {
'weibo.middlewares.RandomUserAgent': 1,
'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware': 110,
'weibo.middlewares.ProxyMiddleware': 100
}这里的weibo可根据你自己scrapy的名称进行替换
接下来添加DOWNLOADER的中间件，在middlewares.py文件中添加如下代码：
class RandomUserAgent(object):
def __init__(self, agents):
self.agents = agents
@classmethod
def from_crawler(cls, crawler):
return cls(crawler.settings.getlist('USER_AGENTS'))
def process_request(self, request, spider):
request.headers.setdefault('User-Agent', random.choice(self.agents))
class ProxyMiddleware(object):
def __init__(self, mysql_host, mysql_db, mysql_user, mysql_passwd):
self.mysql_host = mysql_host
self.mysql_db = mysql_db
self.mysql_user = mysql_user
self.mysql_passwd = mysql_passwd
@classmethod
def from_crawler(cls, crawler):
return cls(
mysql_host=crawler.settings.get('MYSQL_HOST'),
mysql_user=crawler.settings.get('MYSQL_USER'),
mysql_passwd=crawler.settings.get('MYSQL_PASSWD'),
mysql_db=crawler.settings.get('MYSQL_DB')
)
def process_request(self, request, spider):
try:
self.conn = MySQLdb.connect(
user=self.mysql_user,
passwd=self.mysql_passwd,
db=self.mysql_db,
host=self.mysql_host,
charset="utf8",
use_unicode=True
)
self.cursor = self.conn.cursor()
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])
self.cursor.execute(
'SELECT * FROM xicidaili order by verified_time DESC Limit 0,10')
proxy_item = self.cursor.fetchall()
proxy = random.choice(proxy_item)
user_pass = proxy[4]
ip = proxy[1]
port = proxy[2]
http_method = proxy[6]
http_method = http_method.lower()
if user_pass is not None:
request.meta['proxy'] = "%s://%s:%s" % (http_method,ip,port)
encoded_user_pass = base64.encodestring(user_pass)
request.headers[
'Proxy-Authorization'] = 'Basic ' + encoded_user_pass
else:
request.meta['proxy'] = "%s://%s:%s" % (http_method,ip,port)这里提到了代理ip的问题，可以自己去网上搜索一下，然后存储到数据库中，在进行相应的修改【前提是要搞到能用代理ip】
参考的文章：
