Scrapy：TypeError：__ init __（）缺少1个必需的位置参数：'settings'

Question

I have a Scrapy middleware:

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)

But an error occurred when running, what's the settings?

Answer 1

If you need a settings object to initialize your middleware, you need to define a from_crawler() class method, otherwise scrapy initializes the middleware without arguments .

Take a look at the built-in middleware for inspiration, for example 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')

In your case it would be something like:

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)