Scrapy和MongoDB的應用

標籤：

Scrapy是Python開發的一個快速、高層次的螢幕抓取和web抓取架構,用於抓取Web網站並從頁面中提取結構化的資料.它最迷人的地方在於任何人都可以根據需求方便的修改。

MongoDB是現下非常流行的開源的非關係型資料庫（NoSql），它是以“key-value”的形式儲存資料的，在大資料量、高並發、弱事務方面都有很大的優勢。

當Scrapy與MongoDB兩者相碰撞會產生怎樣的火花呢？與MongoDB兩者相碰撞會產生怎樣的火花呢？現在讓我們做一個簡單的爬取小說的TEST

1.安裝Scrapy

pip install scrapy

2.下載安裝MongoDB和MongoVUE可視化

[MongoDB](https://www.mongodb.org/)

下載安裝的步驟略過，在bin目錄下建立一個data檔案夾用來存放資料的。

[MongoVUE](http://www.mongovue.com/)

安裝完成後我們需要建立一個資料庫。

3.建立一個Scrapy項目

scrapy startproject novelspider

目錄結構：其中的novspider.py是需要我們手動建立的(contrloDB不需要理會)

4.編寫代碼

目標網站: http://www.daomubiji.com/

settings.py

BOT_NAME = ‘novelspider‘SPIDER_MODULES = [‘novelspider.spiders‘]NEWSPIDER_MODULE = ‘novelspider.spiders‘ITEM_PIPELINES = [‘novelspider.pipelines.NovelspiderPipeline‘]  #匯入pipelines.py中的方法USER_AGENT = ‘Mozilla/5.0 (Windows NT 6.1; WOW64; rv:39.0) Gecko/20100101 Firefox/39.0‘COOKIES_ENABLED = TrueMONGODB_HOST = ‘127.0.0.1‘   MONGODB_PORT = 27017MONGODB_DBNAME = ‘zzl‘    #資料庫名MONGODB_DOCNAME = ‘Book‘   #表名

pipelines.py

from scrapy.conf import settingsimport pymongoclass NovelspiderPipeline(object):def __init__(self):host = settings[‘MONGODB_HOST‘]port = settings[‘MONGODB_PORT‘]dbName = settings[‘MONGODB_DBNAME‘]client = pymongo.MongoClient(host=host, port=port)tdb = client[dbName]self.post = tdb[settings[‘MONGODB_DOCNAME‘]]def process_item(self, item, spider):bookInfo = dict(item)self.post.insert(bookInfo)return item

items.py

from scrapy import Item,Fieldclass NovelspiderItem(Item):# define the fields for your item here like:# name = scrapy.Field()bookName = Field()bookTitle = Field()chapterNum = Field()chapterName = Field()chapterURL = Field()

在spiders目錄下建立novspider.py

from scrapy.spiders import CrawlSpiderfrom scrapy.selector import Selectorfrom novelspider.items import NovelspiderItemclass novSpider(CrawlSpider):name = "novspider"redis_key = ‘novspider:start_urls‘start_urls = [‘http://www.daomubiji.com/‘]def parse(self,response):selector = Selector(response)table = selector.xpath(‘//table‘)for each in table:bookName = each.xpath(‘tr/td[@colspan="3"]/center/h2/text()‘).extract()[0]content = each.xpath(‘tr/td/a/text()‘).extract()url = each.xpath(‘tr/td/a/@href‘).extract()for i in range(len(url)):item = NovelspiderItem()item[‘bookName‘] = bookNameitem[‘chapterURL‘] = url[i]try:item[‘bookTitle‘] = content[i].split(‘ ‘)[0]item[‘chapterNum‘] = content[i].split(‘ ‘)[1]except Exception,e:continuetry:item[‘chapterName‘] = content[i].split(‘ ‘)[2]except Exception,e:item[‘chapterName‘] = content[i].split(‘ ‘)[1][-3:]yield item

5.啟動項目命令: scrapy crawl novspider.

抓取結果

Scrapy和MongoDB的應用