爬虫框架Scrapy之案例二

Posted 2020-09-02 林深时见鹿

新浪网分类资讯爬虫

爬取新浪网导航页所有下所有大类、小类、小类里的子链接，以及子链接页面的新闻内容。

效果演示图：

 

items.py

import scrapy
import sys
reload(sys)
sys.setdefaultencoding("utf-8")

class SinaItem(scrapy.Item):
    # 大类的标题 和 url
    parentTitle = scrapy.Field()
    parentUrls = scrapy.Field()

    # 小类的标题 和 子url
    subTitle = scrapy.Field()
    subUrls = scrapy.Field()

    # 小类目录存储路径
    subFilename = scrapy.Field()

    # 小类下的子链接
    sonUrls = scrapy.Field()

    # 文章标题和内容
    head = scrapy.Field()
    content = scrapy.Field()

spiders/sina.py

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

from Sina.items import SinaItem
import scrapy
import os

import sys
reload(sys)
sys.setdefaultencoding("utf-8")


class SinaSpider(scrapy.Spider):
    name= "sina"
    allowed_domains= ["sina.com.cn"]
    start_urls= [
       "http://news.sina.com.cn/guide/"
    ]

    def parse(self, response):
        items= []
        # 所有大类的url 和 标题
        parentUrls = response.xpath(\'//div[@id=\\"tab01\\"]/div/h3/a/@href\').extract()
        parentTitle = response.xpath("//div[@id=\\"tab01\\"]/div/h3/a/text()").extract()

        # 所有小类的ur 和 标题
        subUrls  = response.xpath(\'//div[@id=\\"tab01\\"]/div/ul/li/a/@href\').extract()
        subTitle = response.xpath(\'//div[@id=\\"tab01\\"]/div/ul/li/a/text()\').extract()

        #爬取所有大类
        for i in range(0, len(parentTitle)):
            # 指定大类目录的路径和目录名
            parentFilename = "./Data/" + parentTitle[i]

            #如果目录不存在，则创建目录
            if(not os.path.exists(parentFilename)):
                os.makedirs(parentFilename)

            # 爬取所有小类
            for j in range(0, len(subUrls)):
                item = SinaItem()

                # 保存大类的title和urls
                item[\'parentTitle\'] = parentTitle[i]
                item[\'parentUrls\'] = parentUrls[i]

                # 检查小类的url是否以同类别大类url开头，如果是返回True (sports.sina.com.cn 和 sports.sina.com.cn/nba)
                if_belong = subUrls[j].startswith(item[\'parentUrls\'])

                # 如果属于本大类，将存储目录放在本大类目录下
                if(if_belong):
                    subFilename =parentFilename + \'/\'+ subTitle[j]
                    # 如果目录不存在，则创建目录
                    if(not os.path.exists(subFilename)):
                        os.makedirs(subFilename)

                    # 存储 小类url、title和filename字段数据
                    item[\'subUrls\'] = subUrls[j]
                    item[\'subTitle\'] =subTitle[j]
                    item[\'subFilename\'] = subFilename

                    items.append(item)

        #发送每个小类url的Request请求，得到Response连同包含meta数据 一同交给回调函数 second_parse 方法处理
        for item in items:
            yield scrapy.Request( url = item[\'subUrls\'], meta={\'meta_1\': item}, callback=self.second_parse)

    #对于返回的小类的url，再进行递归请求
    def second_parse(self, response):
        # 提取每次Response的meta数据
        meta_1= response.meta[\'meta_1\']

        # 取出小类里所有子链接
        sonUrls = response.xpath(\'//a/@href\').extract()

        items= []
        for i in range(0, len(sonUrls)):
            # 检查每个链接是否以大类url开头、以.shtml结尾，如果是返回True
            if_belong = sonUrls[i].endswith(\'.shtml\') and sonUrls[i].startswith(meta_1[\'parentUrls\'])

            # 如果属于本大类，获取字段值放在同一个item下便于传输
            if(if_belong):
                item = SinaItem()
                item[\'parentTitle\'] =meta_1[\'parentTitle\']
                item[\'parentUrls\'] =meta_1[\'parentUrls\']
                item[\'subUrls\'] = meta_1[\'subUrls\']
                item[\'subTitle\'] = meta_1[\'subTitle\']
                item[\'subFilename\'] = meta_1[\'subFilename\']
                item[\'sonUrls\'] = sonUrls[i]
                items.append(item)

        #发送每个小类下子链接url的Request请求，得到Response后连同包含meta数据 一同交给回调函数 detail_parse 方法处理
        for item in items:
                yield scrapy.Request(url=item[\'sonUrls\'], meta={\'meta_2\':item}, callback = self.detail_parse)

    # 数据解析方法，获取文章标题和内容
    def detail_parse(self, response):
        item = response.meta[\'meta_2\']
        content = ""
        head = response.xpath(\'//h1[@id=\\"main_title\\"]/text()\')
        content_list = response.xpath(\'//div[@id=\\"artibody\\"]/p/text()\').extract()

        # 将p标签里的文本内容合并到一起
        for content_one in content_list:
            content += content_one

        item[\'head\']= head
        item[\'content\']= content

        yield item

pipelines.py

from scrapy import signals
import sys
reload(sys)
sys.setdefaultencoding("utf-8")

class SinaPipeline(object):
    def process_item(self, item, spider):
        sonUrls = item[\'sonUrls\']

        # 文件名为子链接url中间部分，并将 / 替换为 _，保存为 .txt格式
        filename = sonUrls[7:-6].replace(\'/\',\'_\')
        filename += ".txt"

        fp = open(item[\'subFilename\']+\'/\'+filename, \'w\')
        fp.write(item[\'content\'])
        fp.close()

        return item

settings.py

BOT_NAME = \'Sina\'

SPIDER_MODULES = [\'Sina.spiders\']
NEWSPIDER_MODULE = \'Sina.spiders\'

ITEM_PIPELINES = {
    \'Sina.pipelines.SinaPipeline\': 300,
}

LOG_LEVEL = \'DEBUG\'

在项目根目录下新建main.py文件,用于调试

from scrapy import cmdline
cmdline.execute(\'scrapy crawl sina\'.split())

执行程序

py2 main.py