用scrapy爬取亚马逊网站项目

这次爬取亚马逊网站，用到了scrapy，代理池，和中间件：

spiders里面：

# -*- coding: utf-8 -*-
import scrapy

from scrapy.http.request import Request
from urllib.parse import urlencode
from ..items import AmazonItem


class SpiderGoodsSpider(scrapy.Spider):
    name = 'spider_goods'
    allowed_domains = ['www.amazon.cn']
    start_urls = ['http://www.amazon.cn/']

    def __init__(self, keyword, *args, **kwargs):
        super(SpiderGoodsSpider, self).__init__(*args, **kwargs)
        self.keyword = keyword

    def start_requests(self):
        url = 'https://www.amazon.cn/s/ref=nb_sb_noss_1/461-4093573-7508641?'
        url += urlencode({'field-keywords': self.keyword})
        print('初始url',url)
        yield scrapy.Request(url=url,
                              callback=self.parse_index,
                              dont_filter=True)

    def parse_index(self, response):
        detail_urls=response.xpath('//*[contains(@id,"result_")]/div/div[3]/div[1]/a/@href').extract()

        print('所有的url',detail_urls)
        for detail_url in detail_urls:
            yield scrapy.Request(
                url=detail_url,
                callback=self.parse_detail,
                dont_filter=True
            )
        next_url = response.urljoin(response.xpath('//*[@id="pagnNextLink"]/@href').extract_first())
        yield  scrapy.Request(
            url=next_url,
            callback=self.parse_index,
            dont_filter=True
        )

    def parse_detail(self, response):
        print('运行啦+++++++++++++++++')
        name=response.xpath('//*[@id="productTitle"]/text()').extract_first().strip()
        price=response.xpath('//*[@id="priceblock_ourprice"]/text()|//*[@id="priceblock_saleprice"]/text()').extract_first().strip()
        deliver_mothod=''.join(response.xpath('//*[@id="ddmMerchantMessage"]//text()').extract())
        item=AmazonItem()
        item['name']=name
        item['price']=price
        item['delivery_mothod']=deliver_mothod
        print(name,price,deliver_mothod)
        return item

    def close(spider, reason):
        print('结束啦')

 自己定义的url去重规则

'''
if hasattr(MydupeFilter,'from_settings'):
    func=getattr(MydupeFilter,'from_settings')
    obj=func()
else:
    obj=MyDupeFilter()
'''
class MyDupeFilter(object):
    def __init__(self):
        self.visited=set()

    @classmethod
    def from_settings(cls, settings):
        return cls()

    def request_seen(self, request):
        if request.url in self.visited:
            return True
        self.visited.add(request.url)

    def open(self):  # can return deferred
        pass

    def close(self, reason):  # can return a deferred
        pass

    def log(self, request, spider):  # log that a request has been filtered
        pass

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

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

import scrapy


class AmazonItem(scrapy.Item):
    # define the fields for your item here like:
    name = scrapy.Field()
    price = scrapy.Field()
    delivery_mothod = scrapy.Field()

 自己定义的下载中间件：里面meta是用来放代理池的

# -*- 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
from .proxy_handler import get_proxy,delete_proxy

# class AmazonSpiderMiddleware(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 AmazonDownloaderMiddleware(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)
class DownMiddleware(object):
    def  process_request(self,request,spider):
        #返回值None，继续后续中间件去下载；
        #返回值Response，停止process_request的执行，开始执行process_response,
        #返回值Request，停止中间件的执行，直接把这Request对象，放在engine里再放到调度器里。
        #返回值 raise  IgonreRequest异常，停止process_request的执行，开始执行process_exception
       print('下载中间件请求1')
       request.meta['download_timeout'] = 10
       # request.meta['proxy'] = 'https://' + get_proxy()  # 加了代理




    def  process_response(self,request,response,spider):
        #返回值有Response
        # 返回值Request
        # 返回值 raise
        print('下载中间件返回1')


        return  response

    def process_exception(self,request,exception,spider):
        print('异常1')
        # old_proxy=request.meta['proxy'].split('//')[-1]
        # delete_proxy(old_proxy)
        return None

 数据的持久化

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

# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: https://doc.scrapy.org/en/latest/topics/item-pipeline.html


# class AmazonPipeline(object):
#     def process_item(self, item, spider):
#
#         return item


from pymongo import MongoClient
from  scrapy.exceptions import DropItem


class MongoPipline(object):
    def __init__(self, db, collection, host, pwd, port, user):
        self.db = db
        self.collection = collection
        self.host = host
        self.pwd = pwd
        self.port = port
        self.user = user

    @classmethod
    def from_crawler(cls, crawler):
        db = crawler.settings.get('DB')
        collection = crawler.settings.get('COLLECTION')
        host = crawler.settings.get('HOST')
        pwd = crawler.settings.get('PWD')
        port = crawler.settings.getint('PORT')
        user = crawler.settings.get('USER')
        return cls(db, collection, host, pwd, port, user)

    def open_spider(self, spider):
        print(12311111111111111111111111111111)
        self.client = MongoClient("mongodb://%s:%s@%s:%s" % (
            self.user,
            self.pwd,
            self.host,
            self.port
        ))

    def close_spider(self, spider):
        '''关闭爬虫'''
        self.client.close()


    def process_item(self, item, spider):
        d=dict(item)
        print('保存数据',d)
        if all(d.values()):
            self.client[self.db][self.collection].save()
        return item

代理池的：

import requests

def get_proxy():
    return requests.get("http://127.0.0.1:5010/get/").text

def delete_proxy(proxy):
    requests.get("http://127.0.0.1:5010/delete/?proxy={}".format(proxy))

settings里面的代码：

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

# Scrapy settings for Amazon 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


DB='amazon'
COLLECTION='goods'
HOST='localhost'
PORT=27017
USER='root'
PWD='123'





BOT_NAME = 'Amazon'

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


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

# Obey robots.txt rules
ROBOTSTXT_OBEY = False

# 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',
'User-Agent':'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36'
}

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

# Enable or disable downloader middlewares
# See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
# DOWNLOADER_MIDDLEWARES = {
#    'Amazon.middlewares.DownMiddleware': 200,
# }

# 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 = {
   # 'Amazon.pipelines.AmazonPipeline': 300,
   'Amazon.pipelines.MongoPipline': 300,
}

# 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'
DUPEFILTER_CLASS = 'Amazon.cumstomdupefilter.MyDupeFilter'

关于下载中间件：

 def process_request(self, request, spider):
        """
        请求需要被下载时，经过所有下载器中间件的process_request调用
        :param request: 
        :param spider: 
        :return:  
            None,继续后续中间件去下载；
            Response对象，停止process_request的执行，开始执行process_response  #如果返回的是response，就不走下一个requeest直接从最后一个response返回来了
            Request对象，停止中间件的执行，将Request重新调度器#如果返回的是Request对象那就直接到engine，发给调度器
            raise IgnoreRequest异常，停止process_request的执行，开始执行process_exception
        """

 def process_response(self, request, response, spider):
    """
    spider处理完成，返回时调用
    :param response:
    :param result:
    :param spider:
    :return: 
        Response 对象：转交给其他中间件process_response
        Request 对象：停止中间件，request会被重新调度下载
        raise IgnoreRequest 异常：调用Request.errback
    """

def process_exception(self, request, exception, spider):
    """
    当下载处理器(download handler)或 process_request() (下载中间件)抛出异常
    :param response:
    :param exception:
    :param spider:
    :return: 
        None：继续交给后续中间件处理异常；
        Response对象：停止后续process_exception方法
        Request对象：停止中间件，request将会被重新调用下载
    """

代理池的使用：

从github上下载一个代理池的项目：

找到requirements.txt这个文件，看需要哪些配置项：

然后下载

需要更发里面的代码有：

用的是MongoDB的数据库：需要你的用户名，密码，主机名，以及端口号。

在运行爬虫项目之前先运行这个代理池文件：

有了代理后，才有代理可以用来爬取东西.