第二十节：Scrapy爬虫框架之使用Pipeline存储

在上两节当中，我们爬取了360图片，但是我们需要将图片下载下来，这将如何下载和存储呢？

下边叙述一下三种情况：1、将图片下载后存储到MongoDB数据库；2、将图片下载后存储在MySQL数据库；3、将图片下载到本地文件

话不多说，直接上代码：

1、通过item定义存储字段

 # item.py
 import scrapy

 class Bole_mode(scrapy.Item):
     collection = "images"     # collection为MongoDB储表名名称
     table = "images"           # table为MySQL的存储表名名称
     id    = scrapy.Field()      # id
     url   = scrapy.Field()      # 图片链接
     title = scrapy.Field()      # 标题
     thumb = scrapy.Field()  # 缩略图

2、配置settings文件获取数据库信息

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

 # Scrapy settings for bole project
 #
 # For simplicity, this file contains only settings considered important or
 # commonly used. You can find more settings consulting the documentation:
 #
 #     https://doc.scrapy.org/en/latest/topics/settings.html
 #     https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
 #     https://doc.scrapy.org/en/latest/topics/spider-middleware.html

 BOT_NAME = 'bole'

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

 # Crawl responsibly by identifying yourself (and your website) on the user-agent
 #USER_AGENT = 'bole (+http://www.yourdomain.com)'

 # Obey robots.txt rules
 ROBOTSTXT_OBEY = False
 USER_AGENT = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.54 Safari/536.5'

 # Configure maximum concurrent requests performed by Scrapy (default: 16)
 #CONCURRENT_REQUESTS = 32

 # Configure a delay for requests for the same website (default: 0)
 # See https://doc.scrapy.org/en/latest/topics/settings.html#download-delay
 # See also autothrottle settings and docs
 #DOWNLOAD_DELAY = 3
 # The download delay setting will honor only one of:
 #CONCURRENT_REQUESTS_PER_DOMAIN = 16
 #CONCURRENT_REQUESTS_PER_IP = 16

 # Disable cookies (enabled by default)
 #COOKIES_ENABLED = False

 # Disable Telnet Console (enabled by default)
 #TELNETCONSOLE_ENABLED = False

 # Override the default request headers:
 #DEFAULT_REQUEST_HEADERS = {
 #   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
 #   'Accept-Language': 'en',
 #}

 # Enable or disable spider middlewares
 # See https://doc.scrapy.org/en/latest/topics/spider-middleware.html
 #SPIDER_MIDDLEWARES = {
 #    'bole.middlewares.BoleSpiderMiddleware': 543,
 #}

 # Enable or disable downloader middlewares
 # See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html

 # DOWNLOADER_MIDDLEWARES = {
 #    'scrapy.contrib.downloadermiddleware.httpproxy.HttpProxyMiddleware':None,
 #    'bole.middlewares.ProxyMiddleware':125,
 #    'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware':None
 # }

 # Enable or disable extensions
 # See https://doc.scrapy.org/en/latest/topics/extensions.html
 #EXTENSIONS = {
 #    'scrapy.extensions.telnet.TelnetConsole': None,
 #}

 # Configure item pipelines
 # See https://doc.scrapy.org/en/latest/topics/item-pipeline.html
 ITEM_PIPELINES = {
     "bole.pipelines.BoleImagePipeline":2,
     "bole.pipelines.ImagePipeline":300,
     "bole.pipelines.MongoPipeline":301,
     "bole.pipelines.MysqlPipeline":302,
 }

 # Enable and configure the AutoThrottle extension (disabled by default)
 # See https://doc.scrapy.org/en/latest/topics/autothrottle.html
 #AUTOTHROTTLE_ENABLED = True
 # The initial download delay
 #AUTOTHROTTLE_START_DELAY = 5
 # The maximum download delay to be set in case of high latencies
 #AUTOTHROTTLE_MAX_DELAY = 60
 # The average number of requests Scrapy should be sending in parallel to
 # each remote server
 #AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0
 # Enable showing throttling stats for every response received:
 #AUTOTHROTTLE_DEBUG = False

 # Enable and configure HTTP caching (disabled by default)
 # See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings
 #HTTPCACHE_ENABLED = True
 #HTTPCACHE_EXPIRATION_SECS = 0
 #HTTPCACHE_DIR = 'httpcache'
 #HTTPCACHE_IGNORE_HTTP_CODES = []
 #HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'

 # 爬取最大页数
 MAX_PAGE = 50

 # mongodb配置
 MONGODB_URL = "localhost"
 MONGODB_DB = "Images360"

 # MySQL配置
 MYSQL_HOST = "localhost"
 MYSQL_DATABASE = "images360"
 MYSQL_PORT = 3306
 MYSQL_USER = "root"
 MYSQL_PASSWORD = ""

 # 本地配置
 IMAGES_STORE = r"D:\spider\bole\image"

3、此处的Middlewares没有做任何修改

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

 # Define here the models for your spider middleware
 #
 # See documentation in:
 # https://doc.scrapy.org/en/latest/topics/spider-middleware.html

 from scrapy import signals

 class BoleSpiderMiddleware(object):
     # Not all methods need to be defined. If a method is not defined,
     # scrapy acts as if the spider middleware does not modify the
     # passed objects.

     @classmethod
     def from_crawler(cls, crawler):
         # This method is used by Scrapy to create your spiders.
         s = cls()
         crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
         return s

     def process_spider_input(self, response, spider):
         # Called for each response that goes through the spider
         # middleware and into the spider.

         # Should return None or raise an exception.
         return None

     def process_spider_output(self, response, result, spider):
         # Called with the results returned from the Spider, after
         # it has processed the response.

         # Must return an iterable of Request, dict or Item objects.
         for i in result:
             yield i

     def process_spider_exception(self, response, exception, spider):
         # Called when a spider or process_spider_input() method
         # (from other spider middleware) raises an exception.

         # Should return either None or an iterable of Response, dict
         # or Item objects.
         pass

     def process_start_requests(self, start_requests, spider):
         # Called with the start requests of the spider, and works
         # similarly to the process_spider_output() method, except
         # that it doesn’t have a response associated.

         # Must return only requests (not items).
         for r in start_requests:
             yield r

     def spider_opened(self, spider):
         spider.logger.info('Spider opened: %s' % spider.name)

 class BoleDownloaderMiddleware(object):
     # Not all methods need to be defined. If a method is not defined,
     # scrapy acts as if the downloader middleware does not modify the
     # passed objects.

     @classmethod
     def from_crawler(cls, crawler):
         # This method is used by Scrapy to create your spiders.
         s = cls()
         crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
         return s

     def process_request(self, request, spider):
         # Called for each request that goes through the downloader
         # middleware.

         # Must either:
         # - return None: continue processing this request
         # - or return a Response object
         # - or return a Request object
         # - or raise IgnoreRequest: process_exception() methods of
         #   installed downloader middleware will be called
         return None

     def process_response(self, request, response, spider):
         # Called with the response returned from the downloader.

         # Must either;
         # - return a Response object
         # - return a Request object
         # - or raise IgnoreRequest
         return response

     def process_exception(self, request, exception, spider):
         # Called when a download handler or a process_request()
         # (from other downloader middleware) raises an exception.

         # Must either:
         # - return None: continue processing this exception
         # - return a Response object: stops process_exception() chain
         # - return a Request object: stops process_exception() chain
         pass

     def spider_opened(self, spider):
         spider.logger.info('Spider opened: %s' % spider.name)

4、通过Pipeline对爬取的数据进行存储，分为MongoDB数据库存储，MySQL数据库存储，本地文件夹存储

 # -*- coding: utf-8 -*-
 # ==========================MongoDB===========================
 import pymongo
 class MongoPipeline(object):
     def __init__(self,mongodb_url,mongodb_DB):
         self.mongodb_url = mongodb_url
         self.mongodb_DB = mongodb_DB

     @classmethod
     # 获取settings配置文件当中设置的MONGODB_URL和MONGODB_DB
     def from_crawler(cls,crawler):
         return cls(
                     mongodb_url=crawler.settings.get("MONGODB_URL"),
                     mongodb_DB=crawler.settings.get("MONGODB_DB")
                    )

     # 开启爬虫时连接MongoDB数据库
     def open_spider(self,spider):
         self.client = pymongo.MongoClient(self.mongodb_url)
         self.db = self.client[self.mongodb_DB]

     def process_item(self,item,spider):
         table_name = item.collection
         self.db[table_name].insert(dict(item))
         return item

     # 关闭爬虫时断开MongoDB数据库连接
     def close_spider(self,spider):
         self.client.close()

 # ============================MySQL===========================
 import pymysql
 class MysqlPipeline():
     def __init__(self,host,database,port,user,password):
         self.host = host
         self.database = database
         self.port = port
         self.user = user
         self.password = password

     @classmethod
     # 获取settings配置文件当中设置的MySQL各个参数
     def from_crawler(cls,crawler):
         return cls(
             host=crawler.settings.get("MYSQL_HOST"),
             database=crawler.settings.get("MYSQL_DATABASE"),
             port=crawler.settings.get("MYSQL_PORT"),
             user=crawler.settings.get("MYSQL_USER"),
             password=crawler.settings.get("MYSQL_PASSWORD")
         )

     # 开启爬虫时连接MongoDB数据库
     def open_spider(self,spider):
         self.db = pymysql.connect(host=self.host,database=self.database,user=self.user,password=self.password,port=self.port,charset="utf8")
         self.cursor = self.db.cursor()

     def process_item(self,item,spider):
         data = dict(item)
         keys = ",".join(data.keys())            # 字段名
         values =",".join(["%s"]*len(data))     # 值
         sql = "insert into %s(%s) values(%s)"%(item.table, keys, values)
         self.cursor.execute(sql, tuple(data.values()))
         self.db.commit()
         return item

     # 关闭爬虫时断开MongoDB数据库连接
     def close_spider(self,spider):
         self.db.close()

 # # ============================本地===========================
 import scrapy
 from scrapy.exceptions import DropItem
 from scrapy.pipelines.images import ImagesPipeline

 class ImagePipeline(ImagesPipeline):

     # 由于item里的url不是list，所以重写下面几个函数
     def file_path(self, request, response=None, info=None):
         url = request.url
         file_name = url.split("/")[-1]    # 将url连接的最后一部分作为文件名称
         return file_name

     # results为item对应的图片下载的结果，他是一个list，每个元素为元组，并包含了下载成功和失败的信息
     def item_completed(self, results, item, info):

         # 获取图片地址path
         image_paths = [x["path"] for ok,x in results if ok]
         if not image_paths:
             raise DropItem("图片下载失败！！")
         return item

     def get_media_requests(self, item, info):

         # 获取item文件里的url字段并加入队列等待被调用进行下载图片
         yield scrapy.Request(item["url"])

5、最后就是spider数据爬取了

 import scrapy
 import json
 import sys

 sys.path.append(r'D:\spider\bole\item.py')
 from bole.items import Bole_mode

 class BoleSpider(scrapy.Spider):
     name = 'boleSpider'

     def start_requests(self):
         url = "https://image.so.com/zj?ch=photography&sn={}&listtype=new&temp=1"
         page = self.settings.get("MAX_PAGE")
         for i in range(int(page)+1):
             yield scrapy.Request(url=url.format(i*30))

     def parse(self,response):
         photo_list = json.loads(response.text)
         item  = Bole_mode()
         for image in photo_list.get("list"):
             item["id"] = image["id"]
             item["url"] = image["qhimg_url"]
             item["title"] = image["group_title"]
             item["thumb"] = image["qhimg_thumb_url"]
             yield item

6、最最后就是对爬取的结果展示一下呗（只展示MySQL和本地，MongoDB没打开）

（1） MySQL存储

（2） 本地存储