python - Scrapy:类型错误:__init__() 缺少 1 个必需的位置参数: 'settings'

Question

我有一个 Scrapy 中间件:

class ProxyMiddleware(object):
    def __init__(self, settings):
        self.proxy_file = settings.get('PROXY_FILE')
        fin = open(self.proxy_file)
        self.proxy_list = list()
        for line in fin.readlines():
            parts = line.strip().split()
            proxy = parts[2] + '://' + parts[0] + ':' + parts[1]
            self.proxy_list.append(proxy)

    def process_request(self, request, spider):
        request.meta['proxy'] = random.choice(self.proxy_list)

但是运行时出现错误，请问如何设置？

Answer 1

如果您需要一个 settings 对象来初始化中间件，则需要定义一个 from_crawler() 类方法 otherwise scrapy initializes the middleware without arguments .

查看内置中间件以获取灵感，例如 HttpErrorMiddleware

class HttpErrorMiddleware(object):

    @classmethod
    def from_crawler(cls, crawler):
        return cls(crawler.settings)

    def __init__(self, settings):
        self.handle_httpstatus_all = settings.getbool('HTTPERROR_ALLOW_ALL')
        self.handle_httpstatus_list = settings.getlist('HTTPERROR_ALLOWED_CODES')

在你的情况下，它会是这样的:

class ProxyMiddleware(object):

    @classmethod
    def from_crawler(cls, crawler):
        return cls(crawler.settings)

    def __init__(self, settings):
        self.proxy_file = settings.get('PROXY_FILE')
        fin = open(self.proxy_file)
        self.proxy_list = list()
        for line in fin.readlines():
            parts = line.strip().split()
            proxy = parts[2] + '://' + parts[0] + ':' + parts[1]
            self.proxy_list.append(proxy)

    def process_request(self, request, spider):
        request.meta['proxy'] = random.choice(self.proxy_list)