Scrapy框架爬虫

一、sprapy爬虫框架

 pip install pypiwin32 

1) 创建爬虫框架

scrapy startproject Project        # 创建爬虫项目
    You can start your first spider with:
        cd Project
        scrapy genspider example example.com
cd Project    # 进入项目
scrapy genspider chouti chouti.com    # 创建爬虫

2）执行爬虫

class ChoutiSpider(scrapy.Spider):
    name = 'chouti'
    allowed_domains = ['chouti.com']
    # start_urls = ['http://dig.chouti.com/']   #
    start_urls = ['http://www.autohome.com.cn/news']

    def parse(self, response):
        # response 访问网页的后的返回值
        print(response) # <200 https://www.autohome.com.cn/news/>
        print(response.url) # https://www.autohome.com.cn/news/

（debug模式）
scrapy --help 参数帮助
pip install pypiwin32    # 执行爬虫的依赖包
scrapy crawl chouti        # 执行爬虫,查看经过的中间键

# 常用执行爬虫操作
scrapy crawl chouti --nolog        # 执行爬虫

 

3）处理显示编码

import scrapy

import sys
import io
sys.stdout = io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')   # 处理显示编码

class ChoutiSpider(scrapy.Spider):
    .........

    def parse(self, response):
        content = str(response.body,encoding='utf-8')
        print(content)

 4.1）寻找标签：from scrapy.selector import Selector,HtmlXPathSelector

class ChoutiSpider(scrapy.Spider):
    name = 'chouti'
    allowed_domains = ['chouti.com']
    # start_urls = ['http://dig.chouti.com/']
    start_urls = ['http://www.autohome.com.cn/news']

    def parse(self, response):
        '''
        # # response 访问网页的后的返回值
        # print(response) # <200 https://www.autohome.com.cn/news/>
        # # 查看访问的地址
        # print(response.url) # https://www.autohome.com.cn/news/
        # 获取到网页文本代码
        # print(response.text)    # 网页代码
        print(response.body)
        '''

        # 第一种 找到整个文档所有的 a 便签
        # hax = Selector(response=response).xpath('//a')  # 标签对象列表
        # for i in hax:
        #     print(i)    # 便签对象

        # 第二种 找到所有的div标签且属性是 id="content-list"
        # hax = Selector(response=response).xpath('//div[@id="content-list"]').extract()  # 拿到便签非标签对象

        # 第三种 找到所有的div标签且属性是 id="content-list"，并寻找它的儿子标签  （/)
        # hxs = Selector(response=response).xpath('//div[@id="content-list"]/div[@class="item"]').extract()   # 标签对象转换成字符串
        # for i in hxs:
        #     print(i)

        # 第四种 找到所有的div标签且属性是 id="content-list"，并寻找它的儿子标签  （/)
        hxs = Selector(response=response).xpath('//div[@id="content-list"]/div[@class="item"]')
        for obj in hxs:
            # 在当前标签下取所有的a 标签  .//a
            a = obj.xpath('.//a[@class="show-content"]/text()').extract()
            #  a = obj.xpath('.//a[@class="show-content"]/text()').extract_first() # 拿列表的第一个
            # print(a)
            print(a.strip())    # 去除空白

 常用标签寻找总结

//   表示子孙中
.//  当前对象的子孙中
/    儿子
/div 儿子中的div标签
/div[@id="i1"]  儿子中的div标签且id=i1
/div[@id="i1"]  儿子中的div标签且id=i1
obj.extract()         # 列表中的每一个对象转换字符串 =》 []
obj.extract_first()   # 列表中的每一个对象转换字符串 => 列表第一个元素
//div/text()    获取某个标签的文本

hax = Selector(response=response).xpath('//div[@id="dig_lepage"]//a/text()')  # 拿内容
hax = Selector(response=response).xpath('//div[@id="dig_lepage"]//a/@href')  # 拿标签属性

# starts-with(@href, "/all/hot/recent/ 以什么开头
hax = Selector(response=response).xpath('//a[starts-with(@href, "/all/hot/recent/")]/@href').extract()
# 正则取
hxs2 = Selector(response=response).xpath('//a[re:test(@href, "/all/hot/recent/d+")]/@href').extract()

print(response.meta)  查询寻找深度

4.2）所有选择器示例归纳

response = HtmlResponse(url='http://example.com', body=html,encoding='utf-8')
# hxs = HtmlXPathSelector(response)
# print(hxs)
# hxs = Selector(response=response).xpath('//a')
# print(hxs)
# hxs = Selector(response=response).xpath('//a[2]')
# print(hxs)
# hxs = Selector(response=response).xpath('//a[@id]')
# print(hxs)
# hxs = Selector(response=response).xpath('//a[@id="i1"]')
# print(hxs)
# hxs = Selector(response=response).xpath('//a[@href="link.html"][@id="i1"]')
# print(hxs)
# hxs = Selector(response=response).xpath('//a[contains(@href, "link")]')
# print(hxs)
# hxs = Selector(response=response).xpath('//a[starts-with(@href, "link")]')
# print(hxs)
# hxs = Selector(response=response).xpath('//a[re:test(@id, "id+")]')
# print(hxs)
# hxs = Selector(response=response).xpath('//a[re:test(@id, "id+")]/text()').extract()
# print(hxs)
# hxs = Selector(response=response).xpath('//a[re:test(@id, "id+")]/@href').extract()
# print(hxs)
# hxs = Selector(response=response).xpath('/html/body/ul/li/a/@href').extract()
# print(hxs)
# hxs = Selector(response=response).xpath('//body/ul/li/a/@href').extract_first()
# print(hxs)
 
# ul_list = Selector(response=response).xpath('//body/ul/li')
# for item in ul_list:
#     v = item.xpath('./a/span')
#     # 或
#     # v = item.xpath('a/span')
#     # 或
#     # v = item.xpath('*/a/span')
#     print(v)

5.1）获取当前页的所有页面，即a 标签的href属性内容

class ChoutiSpider(scrapy.Spider):
    name = 'chouti'
    allowed_domains = ['chouti.com']
    # start_urls = ['http://dig.chouti.com/']
    start_urls = ['http://www.autohome.com.cn/news']

    visited_urls = set()
    def parse(self, response):
        # 获取当前页的所有页码
        '''
        hax = Selector(response=response).xpath('//div[@id="dig_lepage"]//a/@href').extract()
        for item in hax:
            print(item)     # 可能有重复的页面
        '''
        hax = Selector(response=response).xpath('//div[@id="dig_lepage"]//a/@href').extract()
        for item in hax:
            if item in self.visited_urls:
                print('已经存在')
            else:
                self.visited_urls.add(item)
                print(item)

对url内容加密保存

class ChoutiSpider(scrapy.Spider):
    name = 'chouti'
    allowed_domains = ['chouti.com']
    # start_urls = ['http://dig.chouti.com/']
    start_urls = ['http://www.autohome.com.cn/news']

    visited_urls = set()
    def parse(self, response):
        hax = Selector(response=response).xpath('//div[@id="dig_lepage"]//a/@href').extract()
        for url in hax:
            md5_url = self.md5(url)
            if url in self.visited_urls:
                print('已经存在')
            else:
                self.visited_urls.add(md5_url)
                print(url)

    def md5(self,url):
        import hashlib
        obj = hashlib.md5()
        obj.update(bytes(url,encoding='utf-8'))
        return obj.hexdigest()

5.2）获取该网站的所有页面

# -*- coding: utf-8 -*-
import scrapy
from scrapy.selector import Selector,HtmlXPathSelector
from scrapy.http import Request
import sys
import io
sys.stdout = io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')   # 处理显示编码

class ChoutiSpider(scrapy.Spider):
    name = 'chouti'
    allowed_domains = ['chouti.com']
    # start_urls = ['http://dig.chouti.com/']
    start_urls = ['http://www.autohome.com.cn/news']

    visited_urls = set()
    def parse(self, response):
        hax = Selector(response=response).xpath('//a[starts-with(@href, "/all/hot/recent/")]/@href').extract()
        for url in hax:
            md5_url = self.md5(url)
            if url in self.visited_urls:
                pass
            else:
                print(url)
                self.visited_urls.add(md5_url)
                url = "http://dig.chouti.com%s" %url
                # 将新要访问的url添加到调度器
                yield Request(url=url,callback=self.parse)

    def md5(self,url):
        import hashlib
        obj = hashlib.md5()
        obj.update(bytes(url,encoding='utf-8'))
        return obj.hexdigest()

5.3）设置访问深度，即不获取到所有的页面，递归寻找的层数

#配置文件最后写入
DEPIH_LIMIT = 1

 6）数据保存操作

 配置文件取消注释pipeline

ITEM_PIPELINES = {
   'Project.pipelines.ProjectPipeline': 300,
}

定义保存的数据类字段名

class ChoutiItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    title = scrapy.Field()
    href = scrapy.Field()

将获取的对象传递给pipelines进行持久化保存

    def parse(self, response):
        hxs1 = Selector(response=response).xpath('//div[@id="content-list"]/div[@class="item"]')  # 标签对象列表
        for obj in hxs1:
            title = obj.xpath('.//a[@class="show-content"]/text()').extract_first().strip()
            href =  obj.xpath('.//a[@class="show-content"]/@href').extract_first().strip()
            item_obj = ChoutiItem(title=title,href=href)
            # 将item 对象传递给pipeline
            yield item_obj

6.1）写入文件

class ProjectPipeline(object):
    def process_item(self, item, spider):
        print(spider,item)
        tpl = "%s
%s

" %(item['item'],item['href'])
        f = open('news.json','a')
        f.write(tpl)
        f.close()

7）知识小结

命令：
    scrapy startproject xxx
    cd xxx
    scrapy genspider name  name.com
    scrapy crawl name
编写代码：
    a. name不能省略
    b. start_urls,起始URL地址
    c. allowed_domains = ["chouti.com"] 允许的域名
    d. 重写start_requests，指定初始处理请求的函数
            def start_requests(self):
                for url in self.start_urls:
                    yield Request(url,callback=self.parse1)
    e. 响应response
        repsonse.url
        repsonse.text
        repsonse.body
        response.meta = {'depth': ‘深度’}
        
    f. 采集数据

        Selector(response=response).xpath()
        //div 
        //div[@id="i1"]
        //div[starts-with(@id,"i1")]
        //div[re:test(@id,"i1")]
        //div/a
        # 
        obj.xpath('./')
        obj.xpath('.//')
        
        
        //div/a/text()
        //div/a/@href
        
        Selector().extract()
        Selector().extract_first()
        
        
        //a[@id]
        //a/@id
        
    g. yield Request(url='',callback='xx')
    
    h. yield Item(name='xx',titile='xxx')
        
    i. pipeline
    
        class Foo:
            def process_item(self,item,spider):
                ....
                
        settings = {
            "xx.xx.xxx.Foo1": 300,        # 谁小谁先执行
            "xx.xx.xxx.Foo2": 400,    
        }

二、scrapy框架知识补充

from scrapy.dupefilter import RFPDupeFilter     # 查看去重的url源代码，在编写自己的

1）自定义类，url去重，内容保存方式

class RepeatFilter(object):
    def __init__(self):
        # 2
        self.visited_set = set()
    @classmethod
    def from_settings(cls, settings):
        # 1
        return cls()

    def request_seen(self, request):
        # 4
        if request.url in self.visited_set:
            return True
        self.visited_set.add(request.url)
        return False

    def open(self):  # can return deferred
        # 3
        # print('open')
        pass

    def close(self, reason):  # can return a deferred
        # 5
        # print('close')
        pass
    def log(self, request, spider):  # log that a request has been filtered
        # print('log....')
        pass

 配置文件引入自定义类

DUPEFILTER_CLASS = "day96.duplication.RepeatFilter" # 自定义的
# DUPEFILTER_CLASS = "scrapy.dupefilters.RFPDupeFilter"     # scrapy框架自带的 

主逻辑文件调用回调函数

class ChoutiSpider(scrapy.Spider):
    name = 'chouti'
    allowed_domains = ['chouti.com']
    # start_urls = ['http://dig.chouti.com/']
    start_urls = ['http://www.autohome.com.cn/news']

    def parse(self, response):
        hax2 = Selector(response=response).xpath('//a[starts-with(@href, "/all/hot/recent/")]/@href').extract()
        for url in hax2:
            url = "http://dig.chouti.com%s" %url
            yield Request(url=url,callback=self.parse)

 2.1）pipelines数据库持久化补充（分工明细）

class ProjectPipeline(object):
    def __init__(self,conn_str):
        # 数据的初始化
        self.conn_str = conn_str

    @classmethod
    def from_crawler(cls, crawler):
        """
        初始化时候，用于创建pipeline对象,读取配置文件
        :param crawler:
        :return:
        """
        conn_str = crawler.settings.get('DB')
        return cls(conn_str)

    def open_spider(self,spider):
        """
        爬虫开始执行时，调用
        :param spider:
        :return:
        """
        print('000000')
        self.conn = open(self.conn_str,'a')

    def close_spider(self,spider):
        """
        爬虫关闭时，被调用
        :param spider:
        :return:
        """
        print('1111111')
        self.conn.close()

    def process_item(self, item, spider):
        # 每当数据需要持久化时，就需要被调用
        # if spider.name == "chouti":
        tpl = "%s
%s

" %(item['item'],item['href'])
        self.conn.write(tpl)

 2.2）如果有多个pipelines时，是否考虑让下一个执行

配置文件配置pipelines。根据执行顺序考虑谁先谁后

ITEM_PIPELINES = {
   'day96.pipelines.Day96Pipeline': 300,
   'day96.pipelines.Day97Pipeline': 200,
}

from scrapy.exceptions import DropItem

根据返回值决定是否交给下一个pipelines执行

class ProjectPipeline(object):
    def __init__(self,conn_str):
        # 数据的初始化
        self.conn_str = conn_str

    @classmethod
    def from_crawler(cls, crawler):
        """
        初始化时候，用于创建pipeline对象,读取配置文件
        :param crawler:
        :return:
        """
        conn_str = crawler.settings.get('DB')
        return cls(conn_str)

    def open_spider(self,spider):
        """
        爬虫开始执行时，调用
        :param spider:
        :return:
        """
        print('000000')
        self.conn = open(self.conn_str,'a')

    def close_spider(self,spider):
        """
        爬虫关闭时，被调用
        :param spider:
        :return:
        """
        print('1111111')
        self.conn.close()

    def process_item(self, item, spider):
        # 每当数据需要持久化时，就需要被调用
        # if spider.name == "chouti":
        tpl = "%s
%s

" %(item['item'],item['href'])
        self.conn.write(tpl)
        # 交给下一个pipeline处理
        return item
        # 丢弃item,不交给下一个pipeline处理
        # raise DropItem()

class ProjectPipeline2(object):
    pass

2.3）pipelines总结

pipeline补充
from scrapy.exceptions import DropItem
class Day96Pipeline(object):

    def __init__(self,conn_str):
        self.conn_str = conn_str

    @classmethod
    def from_crawler(cls, crawler):
        """
        初始化时候，用于创建pipeline对象
        :param crawler:
        :return:
        """
        conn_str = crawler.settings.get('DB')
        return cls(conn_str)

    def open_spider(self,spider):
        """
        爬虫开始执行时，调用
        :param spider:
        :return:
        """
        self.conn = open(self.conn_str, 'a')

    def close_spider(self,spider):
        """
        爬虫关闭时，被调用
        :param spider:
        :return:
        """
        self.conn.close()

    def process_item(self, item, spider):
        """
        每当数据需要持久化时，就会被调用
        :param item:
        :param spider:
        :return:
        """
        # if spider.name == 'chouti'
        tpl = "%s
%s

" %(item['title'],item['href'])
        self.conn.write(tpl)
        # 交给下一个pipeline处理
        return item
        # 丢弃item，不交给
        # raise DropItem()

    
    """
    4个方法
    crawler.settings.get('setting中的配置文件名称且必须大写')
    process_item方法中，如果抛出异常DropItem表示终止，否则继续交给后续的pipeline处理
    spider进行判断
    """

3.1）使用cookie登录抽屉，验证是否成功

from scrapy.http.cookies import CookieJar  导入cookies模块

# -*- coding: utf-8 -*-
import scrapy
import sys
import io
from scrapy.http import Request
from scrapy.selector import Selector, HtmlXPathSelector
from ..items import ChoutiItem

sys.stdout = io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')
from scrapy.http.cookies import CookieJar

class ChoutiSpider(scrapy.Spider):
    name = "chouti"
    allowed_domains = ["chouti.com",]
    start_urls = ['http://dig.chouti.com/']

    def parse(self, response):
        cookie_obj = CookieJar()
        cookie_obj.extract_cookies(response,response.request)
        # print(cookie_obj._cookies)  # 查看cookie

        # 带上用户名密码+cookie
        yield Request(
            url="http://dig.chouti.com/login",
            method='POST',
            body = "phone=8615331254089&password=woshiniba&oneMonth=1",
            headers={'Content-Type': "application/x-www-form-urlencoded; charset=UTF-8"},
            cookies=cookie_obj._cookies,
            callback=self.check_login
        )

    def check_login(self,response):
        print(response.text)    # 验证是否登录成功

登录成功的信息

 3.2）首页的当前页点赞

import scrapy
import sys
import io
from scrapy.http import Request
from scrapy.selector import Selector, HtmlXPathSelector
from ..items import ChoutiItem

sys.stdout = io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')
from scrapy.http.cookies import CookieJar

class ChoutiSpider(scrapy.Spider):
    name = "chouti"
    allowed_domains = ["chouti.com",]
    start_urls = ['http://dig.chouti.com/']

    cookie_dict = None
    def parse(self, response):
        cookie_obj = CookieJar()
        cookie_obj.extract_cookies(response,response.request)
        # print(cookie_obj._cookies)  # 查看cookie
        self.cookie_dict = cookie_obj._cookies
        # 带上用户名密码+cookie
        yield Request(
            url="http://dig.chouti.com/login",
            method='POST',
            body = "phone=8615331254089&password=woshiniba&oneMonth=1",
            headers={'Content-Type': "application/x-www-form-urlencoded; charset=UTF-8"},
            cookies=cookie_obj._cookies,
            callback=self.check_login
        )

    def check_login(self,response):
        print(response.text)    # 验证是否登录成功
        # 如果成功
        yield Request(url="http://dig.chouti.com/",callback=self.good)

    def good(self,response):
        id_list = Selector(response=response).xpath('//div[@share-linkid]/@share-linkid').extract()
        for nid in id_list:
            print(nid)
            url = "http://dig.chouti.com/link/vote?linksId=%s" % nid
            yield Request(
                url=url,
                method="POST",
                cookies=self.cookie_dict,
                callback=self.show  # 对发送点赞请求的返回数据
            )

    def show(self,response):
        # 查看是否点赞成功
        print(response.text)

3.3）为所有的页面点赞

# -*- coding: utf-8 -*-
import scrapy
import sys
import io
from scrapy.http import Request
from scrapy.selector import Selector, HtmlXPathSelector
from ..items import ChoutiItem

sys.stdout = io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')
from scrapy.http.cookies import CookieJar

class ChoutiSpider(scrapy.Spider):
    name = "chouti"
    allowed_domains = ["chouti.com",]
    start_urls = ['http://dig.chouti.com/']

    cookie_dict = None
    def parse(self, response):
        cookie_obj = CookieJar()
        cookie_obj.extract_cookies(response,response.request)
        # print(cookie_obj._cookies)  # 查看cookie
        self.cookie_dict = cookie_obj._cookies
        # 带上用户名密码+cookie
        yield Request(
            url="http://dig.chouti.com/login",
            method='POST',
            body = "phone=8615331254089&password=woshiniba&oneMonth=1",
            headers={'Content-Type': "application/x-www-form-urlencoded; charset=UTF-8"},
            cookies=cookie_obj._cookies,
            callback=self.check_login
        )

    def check_login(self,response):
        print(response.text)    # 验证是否登录成功
        # 如果成功
        yield Request(url="http://dig.chouti.com/",callback=self.good)

    def good(self,response):
        id_list = Selector(response=response).xpath('//div[@share-linkid]/@share-linkid').extract()
        for nid in id_list:
            print(nid)
            url = "http://dig.chouti.com/link/vote?linksId=%s" % nid
            yield Request(
                url=url,
                method="POST",
                cookies=self.cookie_dict,
                callback=self.show  # 对发送点赞请求的返回数据
            )

        # 找到所有的页面
        page_urls = Selector(response=response).xpath('//div[@id="dig_lcpage"]//a/@href').extract()
        for page in page_urls:
            url = "http://dig.chouti.com%s" % page
            yield Request(url=url,callback=self.good)   # 回调自己，为所有的页面内容点赞

    def show(self,response):
        # 查看是否点赞成功
        print(response.text)

配置文件设置访问深度，可以指定到页面的深度点赞

3.4）cookies小结

Cookie问题
from scrapy.http.cookies import CookieJar
cookie_obj = CookieJar()
cookie_obj.extract_cookies(response,response.request)
print(cookie_obj._cookies)

4）scrapy框架扩展

 from scrapy.extensions.telnet import TelnetConsole   查看模拟扩展的源代码

自定义扩展内容

from scrapy import signals
class MyExtend:

    def __init__(self,crawler):
        self.crawler = crawler
        # 钩子上挂障碍物
        # 在指定信号上注册操作
        crawler.signals.connect(self.start, signals.engine_started)
        crawler.signals.connect(self.close, signals.spider_closed)

    @classmethod
    def from_crawler(cls, crawler):
        return cls(crawler)

    def start(self):
        print('signals.engine_started.start')

    def close(self):
        print('signals.spider_closed.close')

配置文件引入extension.py

EXTENSIONS = {
   # 'scrapy.extensions.telnet.TelnetConsole': None,
    'day96.extensions.MyExtend': 300,
}

5）配置文件详解

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

# Scrapy settings for step8_king project
#
# For simplicity, this file contains only settings considered important or
# commonly used. You can find more settings consulting the documentation:
#
#     http://doc.scrapy.org/en/latest/topics/settings.html
#     http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html
#     http://scrapy.readthedocs.org/en/latest/topics/spider-middleware.html

# 1. 爬虫名称
BOT_NAME = 'step8_king'

# 2. 爬虫应用路径
SPIDER_MODULES = ['step8_king.spiders']
NEWSPIDER_MODULE = 'step8_king.spiders'

# Crawl responsibly by identifying yourself (and your website) on the user-agent
# 3. 客户端 user-agent请求头
# USER_AGENT = 'step8_king (+http://www.yourdomain.com)'

# Obey robots.txt rules
# 4. 禁止爬虫配置
# ROBOTSTXT_OBEY = False

# Configure maximum concurrent requests performed by Scrapy (default: 16)
# 5. 并发请求数
# CONCURRENT_REQUESTS = 4

# Configure a delay for requests for the same website (default: 0)
# See http://scrapy.readthedocs.org/en/latest/topics/settings.html#download-delay
# See also autothrottle settings and docs
# 6. 延迟下载秒数
# DOWNLOAD_DELAY = 2


# The download delay setting will honor only one of:
# 7. 单域名访问并发数，并且延迟下次秒数也应用在每个域名
# CONCURRENT_REQUESTS_PER_DOMAIN = 2
# 单IP访问并发数，如果有值则忽略：CONCURRENT_REQUESTS_PER_DOMAIN，并且延迟下次秒数也应用在每个IP
# CONCURRENT_REQUESTS_PER_IP = 3

# Disable cookies (enabled by default)
# 8. 是否支持cookie，cookiejar进行操作cookie
# COOKIES_ENABLED = True
# COOKIES_DEBUG = True

# Disable Telnet Console (enabled by default)
# 9. Telnet用于查看当前爬虫的信息，操作爬虫等...
#    使用telnet ip port ，然后通过命令操作
# TELNETCONSOLE_ENABLED = True
# TELNETCONSOLE_HOST = '127.0.0.1'
# TELNETCONSOLE_PORT = [6023,]


# 10. 默认请求头
# 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',
# }


# Configure item pipelines
# See http://scrapy.readthedocs.org/en/latest/topics/item-pipeline.html
# 11. 定义pipeline处理请求
# ITEM_PIPELINES = {
#    'step8_king.pipelines.JsonPipeline': 700,
#    'step8_king.pipelines.FilePipeline': 500,
# }



# 12. 自定义扩展，基于信号进行调用
# Enable or disable extensions
# See http://scrapy.readthedocs.org/en/latest/topics/extensions.html
# EXTENSIONS = {
#     # 'step8_king.extensions.MyExtension': 500,
# }


# 13. 爬虫允许的最大深度，可以通过meta查看当前深度；0表示无深度
# DEPTH_LIMIT = 3

# 14. 爬取时，0表示深度优先Lifo(默认)；1表示广度优先FiFo

# 后进先出，深度优先
# DEPTH_PRIORITY = 0
# SCHEDULER_DISK_QUEUE = 'scrapy.squeue.PickleLifoDiskQueue'
# SCHEDULER_MEMORY_QUEUE = 'scrapy.squeue.LifoMemoryQueue'
# 先进先出，广度优先

# DEPTH_PRIORITY = 1
# SCHEDULER_DISK_QUEUE = 'scrapy.squeue.PickleFifoDiskQueue'
# SCHEDULER_MEMORY_QUEUE = 'scrapy.squeue.FifoMemoryQueue'

# 15. 调度器队列
# SCHEDULER = 'scrapy.core.scheduler.Scheduler'
# from scrapy.core.scheduler import Scheduler


# 16. 访问URL去重
# DUPEFILTER_CLASS = 'step8_king.duplication.RepeatUrl'


# Enable and configure the AutoThrottle extension (disabled by default)
# See http://doc.scrapy.org/en/latest/topics/autothrottle.html

"""
17. 自动限速算法
    from scrapy.contrib.throttle import AutoThrottle
    自动限速设置
    1. 获取最小延迟 DOWNLOAD_DELAY
    2. 获取最大延迟 AUTOTHROTTLE_MAX_DELAY
    3. 设置初始下载延迟 AUTOTHROTTLE_START_DELAY
    4. 当请求下载完成后，获取其"连接"时间 latency，即：请求连接到接受到响应头之间的时间
    5. 用于计算的... AUTOTHROTTLE_TARGET_CONCURRENCY
    target_delay = latency / self.target_concurrency
    new_delay = (slot.delay + target_delay) / 2.0 # 表示上一次的延迟时间
    new_delay = max(target_delay, new_delay)
    new_delay = min(max(self.mindelay, new_delay), self.maxdelay)
    slot.delay = new_delay
"""

# 开始自动限速
# AUTOTHROTTLE_ENABLED = True
# The initial download delay
# 初始下载延迟
# AUTOTHROTTLE_START_DELAY = 5
# The maximum download delay to be set in case of high latencies
# 最大下载延迟
# AUTOTHROTTLE_MAX_DELAY = 10
# The average number of requests Scrapy should be sending in parallel to each remote server
# 平均每秒并发数
# AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0

# Enable showing throttling stats for every response received:
# 是否显示
# AUTOTHROTTLE_DEBUG = True

# Enable and configure HTTP caching (disabled by default)
# See http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings


"""
18. 启用缓存
    目的用于将已经发送的请求或相应缓存下来，以便以后使用
    
    from scrapy.downloadermiddlewares.httpcache import HttpCacheMiddleware
    from scrapy.extensions.httpcache import DummyPolicy
    from scrapy.extensions.httpcache import FilesystemCacheStorage
"""
# 是否启用缓存策略
# HTTPCACHE_ENABLED = True

# 缓存策略：所有请求均缓存，下次在请求直接访问原来的缓存即可
# HTTPCACHE_POLICY = "scrapy.extensions.httpcache.DummyPolicy"
# 缓存策略：根据Http响应头：Cache-Control、Last-Modified 等进行缓存的策略
# HTTPCACHE_POLICY = "scrapy.extensions.httpcache.RFC2616Policy"

# 缓存超时时间
# HTTPCACHE_EXPIRATION_SECS = 0

# 缓存保存路径
# HTTPCACHE_DIR = 'httpcache'

# 缓存忽略的Http状态码
# HTTPCACHE_IGNORE_HTTP_CODES = []

# 缓存存储的插件
# HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'


"""
19. 代理，需要在环境变量中设置
    from scrapy.contrib.downloadermiddleware.httpproxy import HttpProxyMiddleware
    
    方式一：使用默认
        os.environ
        {
            http_proxy:http://root:woshiniba@192.168.11.11:9999/
            https_proxy:http://192.168.11.11:9999/
        }
    方式二：使用自定义下载中间件
    
    def to_bytes(text, encoding=None, errors='strict'):
        if isinstance(text, bytes):
            return text
        if not isinstance(text, six.string_types):
            raise TypeError('to_bytes must receive a unicode, str or bytes '
                            'object, got %s' % type(text).__name__)
        if encoding is None:
            encoding = 'utf-8'
        return text.encode(encoding, errors)
        
    class ProxyMiddleware(object):
        def process_request(self, request, spider):
            PROXIES = [
                {'ip_port': '111.11.228.75:80', 'user_pass': ''},
                {'ip_port': '120.198.243.22:80', 'user_pass': ''},
                {'ip_port': '111.8.60.9:8123', 'user_pass': ''},
                {'ip_port': '101.71.27.120:80', 'user_pass': ''},
                {'ip_port': '122.96.59.104:80', 'user_pass': ''},
                {'ip_port': '122.224.249.122:8088', 'user_pass': ''},
            ]
            proxy = random.choice(PROXIES)
            if proxy['user_pass'] is not None:
                request.meta['proxy'] = to_bytes（"http://%s" % proxy['ip_port']）
                encoded_user_pass = base64.encodestring(to_bytes(proxy['user_pass']))
                request.headers['Proxy-Authorization'] = to_bytes('Basic ' + encoded_user_pass)
                print "**************ProxyMiddleware have pass************" + proxy['ip_port']
            else:
                print "**************ProxyMiddleware no pass************" + proxy['ip_port']
                request.meta['proxy'] = to_bytes("http://%s" % proxy['ip_port'])
    
    DOWNLOADER_MIDDLEWARES = {
       'step8_king.middlewares.ProxyMiddleware': 500,
    }
    
"""

"""
20. Https访问
    Https访问时有两种情况：
    1. 要爬取网站使用的可信任证书(默认支持)
        DOWNLOADER_HTTPCLIENTFACTORY = "scrapy.core.downloader.webclient.ScrapyHTTPClientFactory"
        DOWNLOADER_CLIENTCONTEXTFACTORY = "scrapy.core.downloader.contextfactory.ScrapyClientContextFactory"
        
    2. 要爬取网站使用的自定义证书
        DOWNLOADER_HTTPCLIENTFACTORY = "scrapy.core.downloader.webclient.ScrapyHTTPClientFactory"
        DOWNLOADER_CLIENTCONTEXTFACTORY = "step8_king.https.MySSLFactory"
        
        # https.py
        from scrapy.core.downloader.contextfactory import ScrapyClientContextFactory
        from twisted.internet.ssl import (optionsForClientTLS, CertificateOptions, PrivateCertificate)
        
        class MySSLFactory(ScrapyClientContextFactory):
            def getCertificateOptions(self):
                from OpenSSL import crypto
                v1 = crypto.load_privatekey(crypto.FILETYPE_PEM, open('/Users/wupeiqi/client.key.unsecure', mode='r').read())
                v2 = crypto.load_certificate(crypto.FILETYPE_PEM, open('/Users/wupeiqi/client.pem', mode='r').read())
                return CertificateOptions(
                    privateKey=v1,  # pKey对象
                    certificate=v2,  # X509对象
                    verify=False,
                    method=getattr(self, 'method', getattr(self, '_ssl_method', None))
                )
    其他：
        相关类
            scrapy.core.downloader.handlers.http.HttpDownloadHandler
            scrapy.core.downloader.webclient.ScrapyHTTPClientFactory
            scrapy.core.downloader.contextfactory.ScrapyClientContextFactory
        相关配置
            DOWNLOADER_HTTPCLIENTFACTORY
            DOWNLOADER_CLIENTCONTEXTFACTORY

"""



"""
21. 爬虫中间件
    class SpiderMiddleware(object):

        def process_spider_input(self,response, spider):
            '''
            下载完成，执行，然后交给parse处理
            :param response: 
            :param spider: 
            :return: 
            '''
            pass
    
        def process_spider_output(self,response, result, spider):
            '''
            spider处理完成，返回时调用
            :param response:
            :param result:
            :param spider:
            :return: 必须返回包含 Request 或 Item 对象的可迭代对象(iterable)
            '''
            return result
    
        def process_spider_exception(self,response, exception, spider):
            '''
            异常调用
            :param response:
            :param exception:
            :param spider:
            :return: None,继续交给后续中间件处理异常；含 Response 或 Item 的可迭代对象(iterable)，交给调度器或pipeline
            '''
            return None
    
    
        def process_start_requests(self,start_requests, spider):
            '''
            爬虫启动时调用
            :param start_requests:
            :param spider:
            :return: 包含 Request 对象的可迭代对象
            '''
            return start_requests
    
    内置爬虫中间件：
        'scrapy.contrib.spidermiddleware.httperror.HttpErrorMiddleware': 50,
        'scrapy.contrib.spidermiddleware.offsite.OffsiteMiddleware': 500,
        'scrapy.contrib.spidermiddleware.referer.RefererMiddleware': 700,
        'scrapy.contrib.spidermiddleware.urllength.UrlLengthMiddleware': 800,
        'scrapy.contrib.spidermiddleware.depth.DepthMiddleware': 900,

"""
# from scrapy.contrib.spidermiddleware.referer import RefererMiddleware
# Enable or disable spider middlewares
# See http://scrapy.readthedocs.org/en/latest/topics/spider-middleware.html
SPIDER_MIDDLEWARES = {
   # 'step8_king.middlewares.SpiderMiddleware': 543,
}


"""
22. 下载中间件
    class DownMiddleware1(object):
        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
                Request对象，停止中间件的执行，将Request重新调度器
                raise IgnoreRequest异常，停止process_request的执行，开始执行process_exception
            '''
            pass
    
    
    
        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
            '''
            print('response1')
            return response
    
        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
            '''
            return None

    
    默认下载中间件
    {
        'scrapy.contrib.downloadermiddleware.robotstxt.RobotsTxtMiddleware': 100,
        'scrapy.contrib.downloadermiddleware.httpauth.HttpAuthMiddleware': 300,
        'scrapy.contrib.downloadermiddleware.downloadtimeout.DownloadTimeoutMiddleware': 350,
        'scrapy.contrib.downloadermiddleware.useragent.UserAgentMiddleware': 400,
        'scrapy.contrib.downloadermiddleware.retry.RetryMiddleware': 500,
        'scrapy.contrib.downloadermiddleware.defaultheaders.DefaultHeadersMiddleware': 550,
        'scrapy.contrib.downloadermiddleware.redirect.MetaRefreshMiddleware': 580,
        'scrapy.contrib.downloadermiddleware.httpcompression.HttpCompressionMiddleware': 590,
        'scrapy.contrib.downloadermiddleware.redirect.RedirectMiddleware': 600,
        'scrapy.contrib.downloadermiddleware.cookies.CookiesMiddleware': 700,
        'scrapy.contrib.downloadermiddleware.httpproxy.HttpProxyMiddleware': 750,
        'scrapy.contrib.downloadermiddleware.chunked.ChunkedTransferMiddleware': 830,
        'scrapy.contrib.downloadermiddleware.stats.DownloaderStats': 850,
        'scrapy.contrib.downloadermiddleware.httpcache.HttpCacheMiddleware': 900,
    }

"""
# from scrapy.contrib.downloadermiddleware.httpauth import HttpAuthMiddleware
# Enable or disable downloader middlewares
# See http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html
# DOWNLOADER_MIDDLEWARES = {
#    'step8_king.middlewares.DownMiddleware1': 100,
#    'step8_king.middlewares.DownMiddleware2': 500,
# }

settings

5.1）对于缓存策略选择

# 缓存策略：所有请求均缓存，下次在请求直接访问原来的缓存即可
# HTTPCACHE_POLICY = "scrapy.extensions.httpcache.DummyPolicy"        # 简单粗暴，不建议
# 缓存策略：根据Http响应头：Cache-Control、Last-Modified 等进行缓存的策略
# HTTPCACHE_POLICY = "scrapy.extensions.httpcache.RFC2616Policy"    # 可以使用

# 缓存超时时间
# HTTPCACHE_EXPIRATION_SECS = 0

# 缓存保存路径
# HTTPCACHE_DIR = 'httpcache'

# 缓存忽略的Http状态码
# HTTPCACHE_IGNORE_HTTP_CODES = []

# 缓存存储的插件
# HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'        # 可以使用

6）下载中间键配置

下载中间键编写

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

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

from scrapy import signals
from scrapy.core.engine import ExecutionEngine

class DownMiddleware1(object):
    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
            Request对象，停止中间件的执行，将Request重新调度器
            raise IgnoreRequest异常，停止process_request的执行，开始执行process_exception
        '''
        print('DownMiddleware1.process_request',request.url)

    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
        '''
        print('DownMiddleware1.process_response')
        return response

    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
        '''
        return None


class DownMiddleware2(object):
    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
            Request对象，停止中间件的执行，将Request重新调度器
            raise IgnoreRequest异常，停止process_request的执行，开始执行process_exception
        '''
        print('DownMiddleware2.process_request',request.url)

    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
        '''
        print('DownMiddleware2.process_response')
        return response

配置文件配置

# Enable or disable downloader middlewares
# See http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html
DOWNLOADER_MIDDLEWARES = {
   'day96.middlewares.DownMiddleware1': 540,
   'day96.middlewares.DownMiddleware2': 543,
}

下载中间件运行流程归纳

DownMiddleware1.process_request http://dig.chouti.com/
DownMiddleware2.process_request http://dig.chouti.com/

DownMiddleware2.process_response
DownMiddleware1.process_response

spider.reponse <200 http://dig.chouti.com/>
      
1. process_request下载完成，后续无需下载
2. process_response比如有return response

7）spider 爬虫中间件配置

爬虫中间件编写

class SpiderMiddleware(object):
    def process_spider_input(self, response, spider):
        '''
        下载完成，执行，然后交给parse处理
        :param response:
        :param spider:
        :return:
        '''
        pass

    def process_spider_output(self, response, result, spider):
        '''
        spider处理完成，返回时调用
        :param response:
        :param result:
        :param spider:
        :return: 必须返回包含 Request 或 Item 对象的可迭代对象(iterable)
        '''
        return result

    def process_spider_exception(self, response, exception, spider):
        '''
        异常调用
        :param response:
        :param exception:
        :param spider:
        :return: None,继续交给后续中间件处理异常；含 Response 或 Item 的可迭代对象(iterable)，交给调度器或pipeline
        '''
        return None

    def process_start_requests(self, start_requests, spider):
        '''
        爬虫启动时调用
        :param start_requests:
        :param spider:
        :return: 包含 Request 对象的可迭代对象
        '''
        return start_requests

配置文件配置

# Enable or disable spider middlewares
# See http://scrapy.readthedocs.org/en/latest/topics/spider-middleware.html
SPIDER_MIDDLEWARES = {
   'day96.middlewares.SpiderMiddleware': 543,
}

spcrapy框架链接：https://www.cnblogs.com/linhaifeng/articles/7811861.html