scrapy能够实现先登录再抓取吗

Question

想用python中的scrapy框架抓取网页，但是需要先登录才能显示抓取内容，登录即为一个post操作，但是scrapy中直接通过spider模块的start_url中的url在调度器中生成request，如果需添加post参数是在调试器里添加吗，另外在哪里可以打开并编辑调试器代码？ 求用过scrapy的高手解答？_

Answer 1

class LoginSpider(BaseSpider):
    name = 'example.com'
    start_urls = ['http://www.example.com/users/login.php']

    def parse(self, response):
        return [FormRequest.from_response(response,
                    formdata={'username': 'john', 'password': 'secret'},
                    callback=self.after_login)]

    def after_login(self, response):
        # check login succeed before going on
        if "authentication failed" in response.body:
            self.log("Login failed", level=log.ERROR)
            return

        # continue scraping with authenticated session...
                else:
        return Request(url="http://www.example.com/tastypage/",
               callback=self.parse_tastypage)