crawlspider示例和登录

• 创建crawlspider

scrapy startproject wxapp
cd wxapp
scrapy genspider -t crawl wxappspider www.wxapp-union.com

wxappspider.py文件中：

# -*- coding: utf-8 -*-

'''微信小程序教程页面全部爬取'''
import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from wxapp.items import WxappItem

class WxappSpiderSpider(CrawlSpider):
    name = 'wxapp_spider'
    allowed_domains = ['wxapp-union.com']
    start_urls = ['http://www.wxapp-union.com/portal.php?mod=list&catid=2&page=1']

    rules = (
        # 提取列表页，不用调用回调函数，因为列表页没有什么要爬的
        Rule(LinkExtractor(allow=r'.*?page=\d'), follow=True),
        # 提取具体详情页，调用回调函数，解析具体字段，不继续跟进爬取
        Rule(LinkExtractor(allow=r'.*?article-.*?\.html'),callback='parse_item',follow=False)
    )

    def parse_item(self, response):
        item = WxappItem()
        title = response.xpath('//h1[@class="ph"]/text()').extract()
        item['title'] = title
        yield item

pipelines.py文件中：

from scrapy.exporters import JsonLinesItemExporter

# 保存json文件中
class WxappPipeline(object):
    def __init__(self):
        self.file = open('wxapp.json','wb',)
        self.exporter = JsonLinesItemExporter(self.file,ensure_ascii=False,encoding='utf-8')
    def process_item(self, item, spider):
        self.exporter.export_item(item)
        return item

    def close_spider(self,item,spider):
        self.file.close()

item.py更改的地方：

ROBOTSTXT_OBEY = False
DOWNLOAD_DELAY = 1
DEFAULT_REQUEST_HEADERS = {
  'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
  'Accept-Language': 'en',
    'User-Agent':'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36',
    'Referer': 'http://www.wxapp-union.com/article-4527-1.html'
}
ITEM_PIPELINES = {
   'wxapp.pipelines.WxappPipeline': 300,
}

登录

'''登陆人人网
重写start_requests方法来实现登录'''

import scrapy


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

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


    def parse(self, response):
        pass