Scrapy的补充

windows编码

 

 import sys,os
sys.stdout=io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')
编码

 

 

数据拼接

from urllib.parse import urlencode
v = {
    'k1':'v1',
    'k2':'v2'
}
result = urlencode(v)
print(result)

 结果

k1=v1&k2=v2

 

URL的唯一标识

from scrapy.utils.request import request_fingerprint
from scrapy.http import Request


url1 = "http://www.luffycity.com?k1=123&k2=456"
req1 = Request(url=url1)
url2 = "http://www.luffycity.com?k2=456&k1=123"
req2 = Request(url=url2)

fd1 = request_fingerprint(request=req1)
fd2 = request_fingerprint(request=req2)
print(fd1)
print(fd2)


结果：
500b31c7eed3dee70088a2dcf6c0906713e9d428
500b31c7eed3dee70088a2dcf6c0906713e9d428

 

"""

"""


# 原来
"""
import requests

url_list = ['http://www.baidu.com', 'http://www.baidu.com', 'http://www.baidu.com', ]

for item in url_list:
    response = requests.get(item)
    print(response.text)

"""

# 现在
"""
非阻塞，不等待； 我向贝贝、高件套、小东北发起连接请求时候，不等连接再去连下一个，而是发送一个只会，马上发送下一个。

    import socket 
    sk = socket.socket()
    sk.setblocking(False)
    sk.connect((1.1.1.1,80))
    
    import socket 
    sk = socket.socket()
    sk.setblocking(False)
    sk.connect((1.1.1.2,80))
    
    import socket 
    sk = socket.socket()
    sk.setblocking(False)
    sk.connect((1.1.1.3,80))

异步，回调; 我帮助龙泰、呼呼、刘淞找到想要的人只会，我会主动通知他们。
    def callback(contents):
    print(contents)
事件循环; 我，我一直在循环三个socket任务（即：贝贝、高件套、小东北），检查他三个状态：是否连接成功；是否返回结果。


总结：
    官方：基于事件循环的异步非阻塞模块。
    白话：一个线程同时可以向多个目标发起Http请求。
    
"""

from twisted.web.client import getPage, defer
from twisted.internet import reactor

# 第一部分：代理开始接收任务
def callback(contents):
    print(contents)

deferred_list = [] # [(龙泰,贝贝),(刘淞，宝件套),(呼呼,东北)]
url_list = ['http://www.bing.com', 'https://segmentfault.com/','https://stackoverflow.com/' ]
for url in url_list:
    deferred = getPage(bytes(url, encoding='utf8')) # (我,要谁)
    deferred.addCallback(callback)
    deferred_list.append(deferred)


# # 第二部分：代理执行完任务后，停止
dlist = defer.DeferredList(deferred_list)

def all_done(arg):
    reactor.stop()

dlist.addBoth(all_done)

# 第三部分：代理开始去处理吧
reactor.run()
twisted

 

数据封装

class Request(object):

    def __init__(self,url,callback):
        self.url = url
        self.callback = callback


Request(url='hxfasdfasdfasdf',callback=lambda x:x )

 

去重规则

 scrapy默认使用 scrapy.dupefilter.RFPDupeFilter 进行去重，相关配置有：

DUPEFILTER_CLASS = 'scrapy.dupefilter.RFPDupeFilter'
DUPEFILTER_DEBUG = False
JOBDIR = "保存范文记录的日志路径，如：/root/"  # 最终路径为 /root/requests.seen

from scrapy.dupefilter import BaseDupeFilter
from scrapy.utils.request import request_fingerprint

class XdbDupeFilter(BaseDupeFilter):

    def __init__(self):
        self.visited_fd = set()

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

    def request_seen(self, request):
        fd = request_fingerprint(request=request)
        if fd in self.visited_fd:
            return True
        self.visited_fd.add(fd)

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

    def close(self, reason):  # can return a deferred
        print('结束')

    # def log(self, request, spider):  # log that a request has been filtered
    #     print('日志')
dupefilter
# 修改默认的去重规则
# DUPEFILTER_CLASS = 'scrapy.dupefilter.RFPDupeFilter'
DUPEFILTER_CLASS = 'xdb.dupefiltexrs.XdbDupeFilter'
settings配置

# -*- coding: utf-8 -*-
import scrapy
from scrapy.http.response.html import HtmlResponse
# import sys,os,io
# sys.stdout=io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')
from xdb.items import XdbItem
import scrapy
from scrapy.http.cookies import CookieJar
from scrapy.http import Request
from urllib.parse import urlencode
class ChoutiSpider(scrapy.Spider):
    name = 'chouti'
    allowed_domains = ['chouti.com']
    start_urls = ['https://dig.chouti.com/']
    cookie_dict = {}
    def parse(self, response):
        """
        第一次访问抽屉返回的内容：response
        :param response:
        :return:
        """
        # 去响应头中获取cookie
        # 去响应头中获取cookie，cookie保存在cookie_jar对象
        cookie_jar = CookieJar()
        cookie_jar.extract_cookies(response, response.request)
        # 去对象中将cookie解析到字典
        for k, v in cookie_jar._cookies.items():
            for i, j in v.items():
                for m, n in j.items():
                    self.cookie_dict[m] = n.value
        yield Request(
            url='https://dig.chouti.com/login',
            method='POST',
            body="phone=8613121758648&password=woshiniba&oneMonth=1",# # body=urlencode({})"phone=8615131255555&password=12sdf32sdf&oneMonth=1"
            cookies=self.cookie_dict,
            headers={
                'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'
            },
            callback=self.c

 

cookie处理

 # -*- coding: utf-8 -*-
import scrapy
from scrapy.http.response.html import HtmlResponse
# import sys,os,io
# sys.stdout=io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')
from xdb.items import XdbItem
import scrapy
from scrapy.http.cookies import CookieJar
from scrapy.http import Request
from urllib.parse import urlencode
class ChoutiSpider(scrapy.Spider):
    name = 'chouti'
    allowed_domains = ['chouti.com']
    start_urls = ['https://dig.chouti.com/']
    cookie_dict = {}
    def parse(self, response):
        """
        第一次访问抽屉返回的内容：response
        :param response:
        :return:
        """
        # 去响应头中获取cookie
        # 去响应头中获取cookie，cookie保存在cookie_jar对象
        cookie_jar = CookieJar()
        cookie_jar.extract_cookies(response, response.request)
        # 去对象中将cookie解析到字典
        for k, v in cookie_jar._cookies.items():
            for i, j in v.items():
                for m, n in j.items():
                    self.cookie_dict[m] = n.value
        yield Request(
            url='https://dig.chouti.com/login',
            method='POST',
            body="phone=8613121758648&password=woshiniba&oneMonth=1",# # body=urlencode({})"phone=8615131255555&password=12sdf32sdf&oneMonth=1"
            cookies=self.cookie_dict,
            headers={
                'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'
            },
            callback=self.check_login
手动处理
yield Request(
           url='https://dig.chouti.com/login',
           method='POST',
           body="phone=861300000000&password=12345678&oneMonth=1",#
           cookies=self.cookie_dict,
           headers={
               'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'
           },
           callback=self.check_login
       )
再次请求的时候携带cookie
 自动：****meta={'cookiejar': True}*****
#                 class ChoutiSpider(scrapy.Spider):
#                     name = 'chouti'
#                     allowed_domains = ['chouti.com']
#                     start_urls = ['http://dig.chouti.com/',]
#
#                     def start_requests(self):
#                         for url in self.start_urls:
#                             yield Request(url=url,callback=self.parse_index,meta={'cookiejar':True})
#
#                     def parse_index(self,response):
#                         req = Request(
#                             url='http://dig.chouti.com/login',
#                             method='POST',
#                             headers={'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'},
#                             body='phone=8613121758648&password=woshiniba&oneMonth=1',
#                             callback=self.parse_check_login,
#                             meta={'cookiejar': True}
#                         )
#                         yield req
#
#                     def parse_check_login(self,response):
#                         # print(response.text)
#                         yield Request(
#                             url='https://dig.chouti.com/link/vote?linksId=19440976',
#                             method='POST',
#                             callback=self.parse_show_result,
#                             meta={'cookiejar': True}
#                         )
#
#                     def parse_show_result(self,response):
#                         print(response.text)
自动处理cookie

 

代理

内置代理和自定义代理

方式一
#def start_requests(self):
#     os.environ['HTTP_PROXY'] = "http://root:woshiniba//192.168.11.11"
#     os.environ['HTTPS _PROXY'] = "http://192.168.11.11"




方式二
#     for url in self.start_urls:
#          yield Request(url=url,callback=self.parse,meta={

‘proxy’："http://root:woshiniba//192.168.11.11"

})       

meta中的代理优先
内置代理
# by luffycity.com
import base64
import random
from six.moves.urllib.parse import unquote
try:
    from urllib2 import _parse_proxy
except ImportError:
    from urllib.request import _parse_proxy
from six.moves.urllib.parse import urlunparse
from scrapy.utils.python import to_bytes

class XdbProxyMiddleware(object):

    def _basic_auth_header(self, username, password):
        user_pass = to_bytes(
            '%s:%s' % (unquote(username), unquote(password)),
            encoding='latin-1')
        return base64.b64encode(user_pass).strip()

    def process_request(self, request, spider):
        PROXIES = [
            "http://root:woshiniba@192.168.11.11:9999/",
            "http://root:woshiniba@192.168.11.12:9999/",
            "http://root:woshiniba@192.168.11.13:9999/",
            "http://root:woshiniba@192.168.11.14:9999/",
            "http://root:woshiniba@192.168.11.15:9999/",
            "http://root:woshiniba@192.168.11.16:9999/",
        ]
        url = random.choice(PROXIES)

        orig_type = ""
        proxy_type, user, password, hostport = _parse_proxy(url)
        proxy_url = urlunparse((proxy_type or orig_type, hostport, '', '', '', ''))

        if user:
            creds = self._basic_auth_header(user, password)
        else:
            creds = None
        request.meta['proxy'] = proxy_url
        if creds:
            request.headers['Proxy-Authorization'] = b'Basic ' + creds


class DdbProxyMiddleware(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.b64encode(to_bytes(proxy['user_pass']))
            request.headers['Proxy-Authorization'] = to_bytes('Basic ' + encoded_user_pass)
        else:
            request.meta['proxy'] = to_bytes("http://%s" % proxy['ip_port'])
自定义代理
DOWNLOADER_MIDDLEWARES = {
   #'xdb.middlewares.XdbDownloaderMiddleware': 543,
    'xdb.proxy.XdbProxyMiddleware':751,
}
自定义代理settings的配置

 

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

下载器中间件
下载中间件
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

爬虫中间件
爬虫中间件

下载中间件在每次下载前和下载后对请求和响应可以定制功能，爬虫中间件主要功能是在爬虫运行过程中进行一些处理.

自定义代理使用的就是下载中间件

Downloader Middleware有以下几个函数被管理

- process_request  request通过下载中间件时，该方法被调用

　　 - process_response 下载结果经过中间件时被此方法处理

　　 - process_exception 下载过程中出现异常时被调用

      编写中间件时,需要思考要实现的功能最适合在那个过程处理,就编写哪个方法.

      中间件可以用来处理请求,处理结果或者结合信号协调一些方法的使用等.也可以在原有的爬虫上添加适应项目的其他功能,这一点在扩展中编写也可以达到目的,实际上扩展更加去耦合化,推荐使用扩展.

Spider Middleware有以下几个函数被管理:

- process_spider_input 接收一个response对象并处理,

         位置是Downloader-->process_spider_input-->Spiders(Downloader和Spiders是scrapy官方结构图中的组件)

       - process_spider_exception spider出现的异常时被调用

       - process_spider_output 当Spider处理response返回result时,该方法被调用

       - process_start_requests 当spider发出请求时,被调用

　　  位置是Spiders-->process_start_requests-->Scrapy Engine(Scrapy Engine是scrapy官方结构图中的组件)       

代码示例

from scrapy.http import HtmlResponse
from scrapy.http import Request
 
class Md1(object):
    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        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
        print('md1.process_request',request)
        # 1. 返回Response
        # import requests
        # result = requests.get(request.url)
        # return HtmlResponse(url=request.url, status=200, headers=None, body=result.content)
        # 2. 返回Request
        # return Request('https://dig.chouti.com/r/tec/hot/1')
 
        # 3. 抛出异常
        # from scrapy.exceptions import IgnoreRequest
        # raise IgnoreRequest
 
        # 4. 对请求进行加工(*)
        # request.headers['user-agent'] = "Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36"
 
 
    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
        print('m1.process_response',request,response)
        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
下载中间件
DOWNLOADER_MIDDLEWARES = {
   #'xdb.middlewares.XdbDownloaderMiddleware': 543,
    # 'xdb.proxy.XdbProxyMiddleware':751,
    'xdb.md.Md1':666,
    'xdb.md.Md2':667
settings配置

 

class Sd1(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()
    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
 
# 只在爬虫启动时，执行一次。
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
爬虫中间件
SPIDER_MIDDLEWARES = {
   # 'xdb.middlewares.XdbSpiderMiddleware': 543,
    'xdb.sd.Sd1': 666,
    'xdb.sd.Sd2': 667,
}
settinggs配置

 

定制请求  简化运行命令，一次执行所有爬虫程序

import sys
from scrapy.cmdline import execute

if __name__ == '__main__':
    execute(["scrapy",“crawl“，"chouti","--nolog"])
单个爬虫

多个爬虫文件

  • 在spiders同级创建任意目录，如：commands
  • 在其中创建 crawlall.py 文件 （此处文件名就是自定义的命令）
from scrapy.commands import ScrapyCommand
    from scrapy.utils.project import get_project_settings


    class Command(ScrapyCommand):

        requires_project = True

        def syntax(self):
            return '[options]'

        def short_desc(self):
            return 'Runs all of the spiders'

        def run(self, args, opts):
            spider_list = self.crawler_process.spiders.list()
            for name in spider_list:
                self.crawler_process.crawl(name, **opts.__dict__)
            self.crawler_process.start()

crawlall.py
crawlall
  • 在settings.py 中添加配置 COMMANDS_MODULE = '项目名称.目录名称'
  • 在项目目录执行命令：scrapy crawlall

其他

# -*- 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
View Code

 

posted @ 2019-03-02 14:00  离人怎挽_wdj  阅读(176)  评论(0)  编辑  收藏  举报