• scrapy 高级


    piplines  5个 方法 

    import json
    import os
    import requests
    
    
    class JsonPipeline(object):
        def __init__(self):
            self.file = open('xiaohua.txt', 'w')
    
        def process_item(self, item, spider):
            v = json.dumps(dict(item), ensure_ascii=False)
            self.file.write(v)
            self.file.write('
    ')
            self.file.flush()
            return item
    
    
    class FilePipeline(object):
        def __init__(self):
            if not os.path.exists('imgs'):
                os.makedirs('imgs')
    
        def process_item(self, item, spider):
            response = requests.get(item['url'], stream=True)
            file_name = '%s_%s.jpg' % (item['name'], item['school'])
            with open(os.path.join('imgs', file_name), mode='wb') as f:
                f.write(response.content)
            return item
    
    pipelines
    piplines
    ITEM_PIPELINES = {
       'spider1.pipelines.JsonPipeline': 100,
       'spider1.pipelines.FilePipeline': 300,
    }
    # 每行后面的整型值,确定了他们运行的顺序,item按数字从低到高的顺序,通过pipeline,通常将这些数字定义在0-1000范围内。
    setiings中要打开

    对于pipeline可以做更多,如下:

    from scrapy.exceptions import DropItem
    
    class CustomPipeline(object):
        def __init__(self,v):
            self.value = v
    
        def process_item(self, item, spider):
            # 操作并进行持久化
    
            # return表示会被后续的pipeline继续处理
            return item
    
            # 表示将item丢弃,不会被后续pipeline处理
            # raise DropItem()
    
    
        @classmethod
        def from_crawler(cls, crawler):
            """
            初始化时候,用于创建pipeline对象
            :param crawler: 
            :return: 
            """
            val = crawler.settings.getint('MMMM')
            return cls(val)
    
        def open_spider(self,spider):
            """
            爬虫开始执行时,调用
            :param spider: 
            :return: 
            """
            print('000000')
    
        def close_spider(self,spider):
            """
            爬虫关闭时,被调用
            :param spider: 
            :return: 
            """
            print('111111')
    
    自定义pipeline
    标准写法4+1

    ********************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
    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
    下载器中间件

    =======================自定制命令=========================================

    • 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 执行所有爬虫
    • 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 

    ----------------------------------------------自定义扩展-------------------------------------------------

    自定义扩展时,利用信号在指定位置注册制定操作

    from scrapy import signals
    
    
    class MyExtension(object):
        def __init__(self, value):
            self.value = value
    
        @classmethod
        def from_crawler(cls, crawler):
            val = crawler.settings.getint('MMMM')
            ext = cls(val)
    
            crawler.signals.connect(ext.spider_opened, signal=signals.spider_opened)
            crawler.signals.connect(ext.spider_closed, signal=signals.spider_closed)
    
            return ext
    
        def spider_opened(self, spider):
            print('open')
    
        def spider_closed(self, spider):
            print('close')
    通过scrapy 预留的信号 进行处理

    ******************************************避免重复访问***********************************************

    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
    class RepeatUrl:
        def __init__(self):
            self.visited_url = set()
    
        @classmethod
        def from_settings(cls, settings):
            """
            初始化时,调用
            :param settings: 
            :return: 
            """
            return cls()
    
        def request_seen(self, request):
            """
            检测当前请求是否已经被访问过
            :param request: 
            :return: True表示已经访问过;False表示未访问过
            """
            if request.url in self.visited_url:
                return True
            self.visited_url.add(request.url)
            return False
    
        def open(self):
            """
            开始爬去请求时,调用
            :return: 
            """
            print('open replication')
    
        def close(self, reason):
            """
            结束爬虫爬取时,调用
            :param reason: 
            :return: 
            """
            print('close replication')
    
        def log(self, request, spider):
            """
            记录日志
            :param request: 
            :param spider: 
            :return: 
            """
            print('repeat', request.url)
    
    自定义URL去重操作
    自定义URL 去重
    _------------------------------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
    ***********************************TinyScrapy***********************
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    import types
    from twisted.internet import defer
    from twisted.web.client import getPage
    from twisted.internet import reactor
    
    
    
    class Request(object):
        def __init__(self, url, callback):
            self.url = url
            self.callback = callback
            self.priority = 0
    
    
    class HttpResponse(object):
        def __init__(self, content, request):
            self.content = content
            self.request = request
    
    
    class ChouTiSpider(object):
    
        def start_requests(self):
            url_list = ['http://www.cnblogs.com/', 'http://www.bing.com']
            for url in url_list:
                yield Request(url=url, callback=self.parse)
    
        def parse(self, response):
            print(response.request.url)
            # yield Request(url="http://www.baidu.com", callback=self.parse)
    
    
    
    
    from queue import Queue
    Q = Queue()
    
    
    class CallLaterOnce(object):
        def __init__(self, func, *a, **kw):
            self._func = func
            self._a = a
            self._kw = kw
            self._call = None
    
        def schedule(self, delay=0):
            if self._call is None:
                self._call = reactor.callLater(delay, self)
    
        def cancel(self):
            if self._call:
                self._call.cancel()
    
        def __call__(self):
            self._call = None
            return self._func(*self._a, **self._kw)
    
    
    class Engine(object):
        def __init__(self):
            self.nextcall = None
            self.crawlling = []
            self.max = 5
            self._closewait = None
    
        def get_response(self,content, request):
            response = HttpResponse(content, request)
            gen = request.callback(response)
            if isinstance(gen, types.GeneratorType):
                for req in gen:
                    req.priority = request.priority + 1
                    Q.put(req)
    
    
        def rm_crawlling(self,response,d):
            self.crawlling.remove(d)
    
        def _next_request(self,spider):
            if Q.qsize() == 0 and len(self.crawlling) == 0:
                self._closewait.callback(None)
    
            if len(self.crawlling) >= 5:
                return
            while len(self.crawlling) < 5:
                try:
                    req = Q.get(block=False)
                except Exception as e:
                    req = None
                if not req:
                    return
                d = getPage(req.url.encode('utf-8'))
                self.crawlling.append(d)
                d.addCallback(self.get_response, req)
                d.addCallback(self.rm_crawlling,d)
                d.addCallback(lambda _: self.nextcall.schedule())
    
    
        @defer.inlineCallbacks
        def crawl(self):
            spider = ChouTiSpider()
            start_requests = iter(spider.start_requests())
            flag = True
            while flag:
                try:
                    req = next(start_requests)
                    Q.put(req)
                except StopIteration as e:
                    flag = False
    
            self.nextcall = CallLaterOnce(self._next_request,spider)
            self.nextcall.schedule()
    
            self._closewait = defer.Deferred()
            yield self._closewait
    
        @defer.inlineCallbacks
        def pp(self):
            yield self.crawl()
    
    _active = set()
    obj = Engine()
    d = obj.crawl()
    _active.add(d)
    
    li = defer.DeferredList(_active)
    li.addBoth(lambda _,*a,**kw: reactor.stop())
    
    reactor.run()
    
    参考版
    View Code

    ***********************************scrapy-redis***********************

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  • 原文地址:https://www.cnblogs.com/onda/p/7762310.html
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