Using fromquest in a scratch

scrapy Official access method Request,post Well, that's right scrapy.FormRequest

import scrapy
import requests

class LogingitSpider(scrapy.Spider):
    name = 'logingit'
    allowed_domains = ['github.com']
    #  Login interface URL
    login_url = 'https://github.com/login'
    # POST Form data URL
    post_url = 'https://github.com/session'
    #  After landing URL
    logined_url = 'https://github.com/settings/profile'

    def start_requests(self):
        """
         Get the source code of landing page 
        """
        return [scrapy.Request(url=self.login_url,
                              callback=self.login,
                              headers=self.settings.get('DEFAULT_REQUEST_HEADERS'))]

    def login(self, response):
        """
         Use FromRequest Simulated landing Github
        """
        #  extract POST Verify parameters  authenticity_token
        authcode = response.xpath('//*[@id="login"]/form/input[2]/@value').extract_first()
        if authcode:
            self.logger.debug("Auth Token: %s" %authcode)
            post_data = {
                'commit': 'Sign in',
                'utf8': '*',
                'authenticity_token': authcode,
                'login': self.settings.get('ACCOUNT'),
                'password': self.settings.get('PASSWORD')
            }
            return [scrapy.FormRequest(url=self.post_url,
                                      formdata=post_data,
                                      headers=self.settings.get('DEFAULT_REQUEST_HEADERS'),
                                      callback=self.check)]
        else:
            return [scrapy.Request(url=self.login_url, callback=self.login)]

    def check(self, response):
        """
         Verify whether the login is successful 
        """
        avatar = response.css('#user-links > li:nth-child(3) > details > summary > img::attr(src)').extract_first()
        if avatar:
            content = requests.get(url=avatar.split('?')[0]).content
            with open('./utils/acatar.jpg', 'wb') as f:
                f.write(content)
            print('Successfully Login!')
        pass


    def parse(self, response):
        pass