Python-无法在Scrapy中动态旋转userAgent

我正在覆盖scrapy模块的默认实现HttpProxyMiddleware和UserAgentMiddleware，我自己的scrapy实现会旋转用户代理和IP地址，从提供的列表中随机选择值。每个请求的IP都在更改，但用户代理不会更改。我想不出原因

下面是我的类的实现

RotateUserAgentMiddleware

    class RotateUserAgentMiddleware(UserAgentMiddleware):
    def __init__(self, user_agent=''):
        self.user_agent = user_agent

    def process_request(self, request, spider):
        ua = random.choice(self.user_agent_list)
        if ua:
            request.headers.setdefault('User-Agent', ua)
            # Add desired logging message here.
            spider.log(
                u'User-Agent: {} {}'.format(request.headers.get('User-Agent'), request)
                      )

class ProxyMiddleware(HttpProxyMiddleware):
    def __init__(self, proxy_ip=''):
        self.proxy_ip = proxy_ip

    def process_request(self,request,spider):
        ip = random.choice(self.proxy_list)
        if ip:

            request.meta['proxy'] = ip
            print(request.meta)
        return request

代理中间件

    class RotateUserAgentMiddleware(UserAgentMiddleware):
    def __init__(self, user_agent=''):
        self.user_agent = user_agent

    def process_request(self, request, spider):
        ua = random.choice(self.user_agent_list)
        if ua:
            request.headers.setdefault('User-Agent', ua)
            # Add desired logging message here.
            spider.log(
                u'User-Agent: {} {}'.format(request.headers.get('User-Agent'), request)
                      )

class ProxyMiddleware(HttpProxyMiddleware):
    def __init__(self, proxy_ip=''):
        self.proxy_ip = proxy_ip

    def process_request(self,request,spider):
        ip = random.choice(self.proxy_list)
        if ip:

            request.meta['proxy'] = ip
            print(request.meta)
        return request

settings.py中的Downloader\u中间件中所做的更改是：

DOWNLOADER_MIDDLEWARES = {
    'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware': None,
    'IpRotation.ProxyMiddleware.ProxyMiddleware': 800,
    'scrapy.downloadermiddleware.useragent.UserAgentMiddleware' : None,
    'IpRotation.RotateUserAgentMiddleware.RotateUserAgentMiddleware':790
}

在我的控制台上为每个请求打印的Ip和用户代理值：

    2015-10-09 15:51:46 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '198.*.*.*:80'}
2015-10-09 15:51:46 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '195.*.*.*:3120'}
2015-10-09 15:51:46 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '94.*.*.*:3128'}
2015-10-09 15:51:47 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '94.*.*.*:3128'}
2015-10-09 15:51:47 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '198.*.*.*:80'}
2015-10-09 15:51:47 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '94.*.*.*:3128'}
2015-10-09 15:51:47 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '94.*.*.*:3128'}
2015-10-09 15:51:47 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '195.*.*.*:3120'}
2015-10-09 15:51:47 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '200.*.*.*:80'}
2015-10-09 15:51:47 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '198.*.*.*:80'}
2015-10-09 15:51:47 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '213.*.*.*:80'}
2015-10-09 15:51:47 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '198.*.*.*:80'}
2015-10-09 15:51:47 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '200.*.*.*:80'}
2015-10-09 15:51:48 [dmoz] DEBUG: User-Agent: Scrapy/1.0.3 (+http://scrapy.org) <GET http://www.imdb.com/chart/top>
{'download_timeout': 180.0, 'proxy': '58.*.*.*:80'}

---

在整个项目中，我不清楚的地方是将值分配给Downloader\u中间件。没有人说scrapy忽略这个类，但是整数说什么呢？请有人从这里帮我。

将Downloader_Middleware中的“IpRotation.RotateUserAgentMiddleware.RotateUserAgentMiddleware”的值更改为小于400