python scrapy版 极客学院爬虫V2

1 基本技术 使用scrapy

2 这个爬虫的难点是 Request中的headers和cookies 尝试过好多次才成功（模拟登录），否则只能抓免费课程

3文件树如下

│ jike.json 存储json文件
│ run.py 运行爬虫
└─jkscrapy
│ items.py 设置字段
│ pipelines.py 处理字段
│ settings.py 基本设置
│ init.py
└─spiders
jkspiders.py 爬虫
jkspiders.pyc
init.py

# coding:utf-8from jkscrapy.items import JkscrapyItemfrom scrapy.http import Requestimport refrom scrapy.spiders import BaseSpiderfrom scrapy.selector import Selectorfrom jkscrapy.settings import *import sysreload(sys)sys.setdefaultencoding("utf-8")

爬虫

class jikespider(BaseSpider):    name = "jike"    base_url = "http://www.jikexueyuan.com/course/"    start_urls = ["http://www.jikexueyuan.com/"]    allowed_domains = ["www.jikexueyuan.com", "search.jikexueyuan.com", "jikexueyuan.com"]    def __init__(self):        self.headers = headers        self.cookies = cookies        pass

爬虫 重写 BaseSpider parse

-1、在首页中获取标签及课程对应的地址
-2、eghttp://www.jikexueyuan.com/course/python/

    def parse(self, response):        s_total = Selector(text=response.body).xpath(            '//*[@id="pager"]/div[1]/div[1]/ul/li/div/div/div/dl/dd/a/@href').extract()        if len(s_total) > 0:            for page in s_total:                yield Request(page, callback=self.get_course_pages,headers=self.headers,cookies=self.cookies)        else:            pass

爬虫 get_course_pages 获取课程连接

-1、scrapy Selector xpath 获取课程地址
-2、eg http://www.jikexueyuan.com/course/1860.html

    def get_course_pages(self, response):        x_couses = Selector(text=response.body).xpath('//*[@id="changeid"]/ul/li/div[1]/a')        for x in x_couses:            try:                href = x.select('@href').extract()[0]                title = x.select('img/@title').extract()[0]                yield Request(href, callback=self.get_course_detail,headers=self.headers,cookies=self.cookies)            except:                pass

爬虫 get_course_detail获取课程

-1、scrapy Selector xpath 获取课程地址
-2、eg http://www.jikexueyuan.com/course/271_3.html?ss=1

    def get_course_detail(self, response):        d_couses = Selector(text=response.body).xpath('//*[@id="pager"]/div[3]/div[2]/div[2]/ul/li/div/h2/a')        for d in d_couses:            try:                href = d.select('@href').extract()[0]                print(href)                title = d.select('text()').extract()[0]                # print("         %s %s" % (href, title))                meta = {}                meta["href"] = href                meta["title"] = title                yield Request(href, callback=self.get_down_urls, meta={"meta": meta},headers=self.headers,cookies=self.cookies)            except:                pass

爬虫 get_down_urls获取课程下地址

-1、正则 获取课程下载地址，这个是调用flash播放地址 尝试过很多方法 最后发现正则可以
-2、eg http://cv3.jikexueyuan.com/201509071527/df51514a02286dac0b30245eaa4dd166/html5/course_mob/01/video/c271b_03_h264_sd_960_540.mp4

    def get_down_urls(self, response):        meta = response.meta["meta"]        course_down = re.findall(r'source src="(.*?)"', response.body, re.S)        item = JkscrapyItem()        if course_down:            item["course_id"] = meta["href"]            item["course_name"] = meta["title"]            item["course_path"] = course_down[0]            yield item

爬虫为了测试简要的存储为json 结果只存储了几个字段，可以根据需要进行调整共爬取了4500多条