Spider.parse callback is not defined

Spider.parse callback is not defined

在scrapy中，用FormRequest写post请求登陆人人网的时候，报错Spider.parse callback is not defined

代码是这样的

# -*- coding: utf-8 -*-
import scrapy
# from scrapy.spiders import CrawlSpider

class RenrenSpider(scrapy.Spider):
# class RenrenSpider(CrawlSpider):
    name = 'renren'
    allowed_domains = ['renren.com']
    start_urls = ['http://renren.com/']

    # def parse(self, response):
    #     pass

    def start_request(self):
        url = 'http://www.renren.com/PLogin.do'
        data = {
    
    'email':'youremail', 'password':'yourpassword'}
        request = scrapy.FormRequest(url, formdata=data, callback=self.parse_page)
        yield request

    def parse_page(self, response):
        with open('renren.html', 'w', encoding='utf-8') as fp:
            fp.write(response.text)

查找相关贴子，说要继承CrawlSpider类，修改后还是不行。
试着将回调函数的名字改为parse，结果成功了。

# -*- coding: utf-8 -*-
import scrapy
# from scrapy.spiders import CrawlSpider

class RenrenSpider(scrapy.Spider):
# class RenrenSpider(CrawlSpider):
    name = 'renren'
    allowed_domains = ['renren.com']
    start_urls = ['http://renren.com/']

    # def parse(self, response):
    #     pass

    def start_request(self):
        url = 'http://www.renren.com/PLogin.do'
        data = {
    
    'email':'[email protected]', 'password':'pythonspider'}
        request = scrapy.FormRequest(url, formdata=data, callback=self.parse)
        yield request

    def parse(self, response):
        with open('renren.html', 'w', encoding='utf-8') as fp:
            fp.write(response.text)