当信息可能通过ajax传输时，如何使用scrapy模拟登录过程？

import scrapy
from scrapy.http import FormRequest

class LoginSpider(scrapy.Spider):
    name = 'login'
    start_urls = ['http://example.com/login']

    def parse(self, response):
        # 提取登录页面中的表单数据
        formdata = {
            'username': 'your_username',
            'password': 'your_password'
        }
        # 发送POST请求，模拟登录
        yield FormRequest.from_response(response, formdata=formdata, callback=self.after_login)

    def after_login(self, response):
        # 验证登录是否成功
        if "Welcome" in response.text:
            self.logger.info("Login successful!")
            # 在这里可以继续爬取需要登录后才能访问的页面
        else:
            self.logger.error("Login failed!")

DOWNLOADER_MIDDLEWARES = {
    'scrapy.downloadermiddlewares.cookies.CookiesMiddleware': 700,
    'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware': None,
    'scrapy_fake_useragent.middleware.RandomUserAgentMiddleware': 400,
}

scrapy crawl login