scrapy之Pymongo

用Pymongo保存数据

爬取豆瓣电影top250movie.douban.com/top250的电影数据，并保存在MongoDB中。

items.py

class DoubanspiderItem(scrapy.Item):
    # 电影标题
    title = scrapy.Field()
    # 电影评分
    score = scrapy.Field()
    # 电影信息
    content = scrapy.Field()
    # 简介
    info = scrapy.Field()

spiders/douban.py

import scrapy
from doubanSpider.items import DoubanspiderItem

class DoubanSpider(scrapy.Spider):
    name = "douban"
    allowed_domains = ["movie.douban.com"]
    start = 0
    url = 'https://movie.douban.com/top250?start='
    end = '&filter='
    start_urls = [url + str(start) + end]

    def parse(self, response):

        item = DoubanspiderItem()

        movies = response.xpath("//div[@class=\'info\']")

        for each in movies:
            title = each.xpath('div[@class="hd"]/a/span[@class="title"]/text()').extract()
            content = each.xpath('div[@class="bd"]/p/text()').extract()
            score = each.xpath('div[@class="bd"]/div[@class="star"]/span[@class="rating_num"]/text()').extract()
            info = each.xpath('div[@class="bd"]/p[@class="quote"]/span/text()').extract()

            item['title'] = title[0]
            # 以;作为分隔，将content列表里所有元素合并成一个新的字符串
            item['content'] = ';'.join(content)
            item['score'] = score[0]
            item['info'] = info[0]
            # 提交item

            yield item

        if self.start <= 225:
            self.start += 25
            yield scrapy.Request(self.url + str(self.start) + self.end, callback=self.parse)

pipelines.py

from scrapy.conf import settings
import pymongo

class DoubanspiderPipeline(object):
    def __init__(self):
        # 获取setting主机名、端口号和数据库名
        host = settings['MONGODB_HOST']
        port = settings['MONGODB_PORT']
        dbname = settings['MONGODB_DBNAME']

        # pymongo.MongoClient(host, port) 创建MongoDB链接
        client = pymongo.MongoClient(host=host,port=port)

        # 指向指定的数据库
        mdb = client[dbname]
        # 获取数据库里存放数据的表名
        self.post = mdb[settings['MONGODB_DOCNAME']]

    def process_item(self, item, spider):
        data = dict(item)
        # 向指定的表里添加数据
        self.post.insert(data)
        return item

settings.py

BOT_NAME = 'doubanSpider'

SPIDER_MODULES = ['doubanSpider.spiders']
NEWSPIDER_MODULE = 'doubanSpider.spiders'

ITEM_PIPELINES = {
        'doubanSpider.pipelines.DoubanspiderPipeline' : 300
        }

# Crawl responsibly by identifying yourself (and your website) on the user-agent
USER_AGENT = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.116 Safari/537.36'

# MONGODB 主机环回地址127.0.0.1
MONGODB_HOST = '127.0.0.1'
# 端口号，默认是27017
MONGODB_PORT = 27017
# 设置数据库名称
MONGODB_DBNAME = 'DouBan'
# 存放本次数据的表名称
MONGODB_DOCNAME = 'DouBanMovies'

运行

启动MongoDB数据库需要两个命令：

mongod：是mongoDB数据库进程本身
mongo：是命令行shell客户端

sudo mongod # 首先启动数据库服务，再执行Scrapy
sudo mongo # 启动数据库shell

在mongo shell下使用命令:

# 查看当前数据库
> db

# 列出所有的数据库
> show dbs

# 连接DouBan数据库
> use DouBan

# 列出所有表
> show collections

# 查看表里的数据
> db.DouBanMoives.find()