Python使用scrapy爬取陽光熱線問政平臺過程解析

更新時間：2019年08月14日 09:57:42 作者：silence-cc

這篇文章主要介紹了Python使用scrapy爬取陽光熱線問政平臺過程解析,文中通過示例代碼介紹的非常詳細，對大家的學習或者工作具有一定的參考學習價值,需要的朋友可以參考下

目的：爬取陽光熱線問政平臺問題反映每個帖子里面的標題、內(nèi)容、編號和帖子url

CrawlSpider版流程如下：

創(chuàng)建爬蟲項目dongguang

scrapy startproject dongguang

設(shè)置items.py文件

# -*- coding: utf-8 -*-
import scrapy
class NewdongguanItem(scrapy.Item):
  # define the fields for your item here like:
  # name = scrapy.Field()
  # pass
  # 每頁的帖子鏈接
  url = scrapy.Field()
  # 帖子標題
  title = scrapy.Field()
  # 帖子編號
  number = scrapy.Field()
  # 帖子內(nèi)容
  content = scrapy.Field()

在spiders目錄里面，創(chuàng)建并編寫爬蟲文件sun.py

# -*- coding: utf-8 -*-
import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from dongguan.items import DongguanItem
class SunSpider(CrawlSpider):
  name = 'dg'
  allowed_domains = ['wz.sun0769.com']
  start_urls = ['http://wz.sun0769.com/html/top/report.shtml']
  # rules是Rule的集合，每個rule規(guī)則同時執(zhí)行。另外，如果發(fā)現(xiàn)web服務(wù)器有反爬蟲機制如返回一個假的url，則可以使用Rule里面的參數(shù)process_links調(diào)用一個自編函數(shù)來處理url后返回一個真的url
  rules = (
    # 每個url都有一個獨一無二的指紋，每個爬蟲項目都有一個去重隊列
    # Rule里面沒有回調(diào)函數(shù)，則默認對匹配的鏈接要跟進，就是對匹配的鏈接在進行請求獲取響應(yīng)后對響應(yīng)里面匹配的鏈接繼續(xù)跟進，只不過沒有回調(diào)函數(shù)對響應(yīng)數(shù)據(jù)進行處理
    # Rule(LinkExtractor(allow="page="))如果設(shè)置為follow=False,則不會跟進，只顯示當前頁面匹配的鏈接。如設(shè)置為follow=True，則會對每個匹配的鏈接發(fā)送請求獲取響應(yīng)進而從每個響應(yīng)里面再次匹配跟進，直至沒有。python遞歸深度默認為不超過1000，否則會報異常
    Rule(LinkExtractor(allow="page=")),

    Rule(LinkExtractor(allow='http://wz.sun0769.com/html/question/\d+/\d+.shtml'),callback='parse_item')

  )

  def parse_item(self, response):
    print(response.url)
    item = DongguanItem()
    item['url'] = response.url
    item['title'] = response.xpath('//div[@class="pagecenter p3"]//strong/text()').extract()[0]
    item['number'] = response.xpath('//div[@class="pagecenter p3"]//strong/text()').extract()[0].split(' ')[-1].split(':')[-1]
     # 對帖子里面有圖片的處理，發(fā)現(xiàn)沒有圖片時則沒有class="contentext"的div標簽，以此作為標準獲取帖子內(nèi)容
    if len(response.xpath('//div[@class="contentext"]')) == 0:
      item['content'] = ''.join(response.xpath('//div[@class="c1 text14_2"]/text()').extract())
    else:
      item['content'] = ''.join(response.xpath('//div[@class="contentext"]/text()').extract())
    yield item

編寫管道pipelines.py文件

# -*- coding: utf-8 -*-
import json
class DongguanPipeline(object):
  def __init__(self):
    self.file = open('dongguan.json','w')
  def process_item(self, item, spider):
    content = json.dumps(dict(item),ensure_ascii=False).encode('utf-8') + '\n'
    self.file.write(content)
    return item
  def closespider(self):
    self.file.close()

編寫settings.py文件

# -*- coding: utf-8 -*-
BOT_NAME = 'dongguan'
SPIDER_MODULES = ['dongguan.spiders']
NEWSPIDER_MODULE = 'dongguan.spiders'
# log日志文件默認保存在當前目錄，下面為日志級別，當大于或等于INFO時將被保存
LOG_FILE = 'dongguan.log'
LOG_LEVEL = 'INFO'
# 爬取深度設(shè)置
# DEPTH_LIMIT = 1
# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'dongguan (+http://www.yourdomain.com)'
# Obey robots.txt rules
# ROBOTSTXT_OBEY = True
# Configure maximum concurrent requests performed by Scrapy (default: 16)
#CONCURRENT_REQUESTS = 32
# Configure item pipelines
# See https://doc.scrapy.org/en/latest/topics/item-pipeline.html
ITEM_PIPELINES = {
  'dongguan.pipelines.DongguanPipeline': 300,
}

測試運行爬蟲，終端執(zhí)行命令（只要在項目目錄內(nèi)即可）

scrapy crawl dg

Spider版流程如下：

創(chuàng)建爬蟲項目newdongguang

scrapy startproject newdongguan

設(shè)置items.py文件

# -*- coding: utf-8 -*-
  import scrapy
  class NewdongguanItem(scrapy.Item):
    # 每頁的帖子鏈接
    url = scrapy.Field()
    # 帖子標題
    title = scrapy.Field()
    # 帖子編號
    number = scrapy.Field()
    # 帖子內(nèi)容
    content = scrapy.Field()

在spiders目錄里面，創(chuàng)建并編寫爬蟲文件newsun.py

# -*- coding: utf-8 -*-
import scrapy
from newdongguan.items import NewdongguanItem
class NewsunSpider(scrapy.Spider):
  name = 'ndg'
  # 設(shè)置爬取的域名范圍，可寫可不寫，不寫則表示爬取時候不限域名，結(jié)果有可能會導(dǎo)致爬蟲失控。
  allowed_domains = ['wz.sun0769.com']
  offset = 0
  url = 'http://wz.sun0769.com/index.php/question/report?page=' + str(offset)
  start_urls = [url]
  def parse(self, response):
    link_list = response.xpath("http://a[@class='news14']/@href").extract()
    for each in link_list:
      # 對每頁的帖子發(fā)送請求，獲取帖子內(nèi)容里面指定數(shù)據(jù)返回給管道文件
      yield scrapy.Request(each,callback=self.deal_link)
    self.offset += 30
    if self.offset <= 124260:
      url = 'http://wz.sun0769.com/index.php/question/report?page=' + str(self.offset)
      # 對指定分頁發(fā)送請求，響應(yīng)交給parse函數(shù)處理
      yield scrapy.Request(url,callback=self.parse)

  # 從每個分頁帖子內(nèi)容獲取數(shù)據(jù)，返回給管道
  def deal_link(self,response):
    item = NewdongguanItem()
    item['url'] = response.url
    item['title'] = response.xpath("http://div[@class='pagecenter p3']//strong[@class='tgray14']/text()").extract()[0]
    item['number'] = response.xpath("http://div[@class='pagecenter p3']//strong[@class='tgray14']/text()").extract()[0].split(' ')[-1].split(':')[-1]

    if len(response.xpath("http://div[@class='contentext']")) == 0:
      item['content'] = ''.join(response.xpath("http://div[@class='c1 text14_2']/text()").extract())
    else:
      item['content'] = ''.join(response.xpath("http://div[@class='contentext']/text()").extract())
    yield item

編寫管道pipelines.py文件

# -*- coding: utf-8 -*-
import codecs
import json
class NewdongguanPipeline(object):

  def __init__(self):
    # 使用codecs寫文件，直接設(shè)置文件內(nèi)容編碼格式，省去每次都要對內(nèi)容進行編碼
    self.file = codecs.open('newdongguan.json','w',encoding = 'utf-8')
    # 以前文件寫法
    # self.file = open('newdongguan.json','w')

  def process_item(self, item, spider):
    print(item['title'])
    content = json.dumps(dict(item),ensure_ascii=False) + '\n'
    # 以前文件寫法
    # self.file.write(content.encode('utf-8'))
    self.file.write(content)
    return item

  def close_spider(self):
    self.file.close()

編寫settings.py文件

# -*- coding: utf-8 -*-
BOT_NAME = 'newdongguan'
SPIDER_MODULES = ['newdongguan.spiders']
NEWSPIDER_MODULE = 'newdongguan.spiders'
# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'newdongguan (+http://www.yourdomain.com)'
USER_AGENT = 'User-Agent:Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0;'
# Configure item pipelines
# See https://doc.scrapy.org/en/latest/topics/item-pipeline.html
ITEM_PIPELINES = {
  'newdongguan.pipelines.NewdongguanPipeline': 300,
}

測試運行爬蟲，終端執(zhí)行命