scrapy 相关

Spider类的一些自定制

# Spider类 自定义  起始解析器
 def start_requests(self):
        for url in self.start_urls:
            yield Request(url=url,callback=self.myparse)
 
# 起始会先经过这个视图函数返回一个 列表或者 一个生成器

yield Request(url=page_url, callback=self.parse)  #指定解析函数

parse函数的参数之response

# print(response.request)  # 将请求对象也封装在了response中
# print(response.url)   #  请求的url
# print(response.headers)  # 响应的头
# print(response.headers['Set-Cookie'])  # 原始cookies
 
['_auto_detect_fun', '_body', '_body_declared_encoding', '_body_inferred
_encoding', '_cached_benc', '_cached_selector', '_cached_ubody', '_declared_encoding', '_encoding', '_get_body', '_get_url', '_headers_encoding', '_se
t_body', '_set_url', '_url', 'body', 'body_as_unicode', 'copy', 'css', 'encoding', 'flags', 'follow', 'headers', 'meta', 'replace', 'request', 'select
or', 'status', 'text', 'url', 'urljoin', 'xpath']

参数

获取状态码 response.status

CookiesMiddleware

class scrapy.contrib.downloadermiddleware.cookies.CookiesMiddleware

该中间件使得爬取需要cookie(例如使用session)的网站成为了可能。 其追踪了web server发送的cookie，并在之后的request中发送回去， 就如浏览器所做的那样。

以下设置可以用来配置cookie中间件:

• COOKIES_ENABLED
• COOKIES_DEBUG

单spider多cookie session

0.15 新版功能.

Scrapy通过使用 cookiejar Request meta key来支持单spider追踪多cookie session。 默认情况下其使用一个cookie jar(session)，不过您可以传递一个标示符来使用多个。

例如:

for i, url in enumerate(urls):
    yield scrapy.Request("http://www.example.com", meta={'cookiejar': i},
        callback=self.parse_page)

需要注意的是 cookiejar meta key不是”黏性的(sticky)”。 您需要在之后的request请求中接着传递。例如:

def parse_page(self, response):
    # do some processing
    return scrapy.Request("http://www.example.com/otherpage",
        meta={'cookiejar': response.meta['cookiejar']},
        callback=self.parse_other_page)

# from scrapy.http.cookies import CookieJar
# cookiejar = CookieJar()
# cookiejar.extract_cookies(response, response.request)
# temp = {}
# for k, v in cookiejar._cookies.items():
#     for i, j in v.items():
#         for m, n in j.items():
#             temp[m] = n.value
# self.cookie_dic.update(temp)
yeild Request(url=url,
cookies = self.cookie_dic
)
# 该方法是原始的手动操作cookie

COOKIES_ENABLED

默认: True

是否启用cookies middleware。如果关闭，cookies将不会发送给web server。

COOKIES_DEBUG

默认: False

如果启用，Scrapy将记录所有在request(Cookie 请求头)发送的cookies及response接收到的cookies(Set-Cookie 接收头)。

下边是启用 COOKIES_DEBUG 的记录的样例:

2011-04-06 14:35:10-0300 [diningcity] INFO: Spider opened
2011-04-06 14:35:10-0300 [diningcity] DEBUG: Sending cookies to: <GET http://www.diningcity.com/netherlands/index.html>
        Cookie: clientlanguage_nl=en_EN
2011-04-06 14:35:14-0300 [diningcity] DEBUG: Received cookies from: <200 http://www.diningcity.com/netherlands/index.html>
        Set-Cookie: JSESSIONID=B~FA4DC0C496C8762AE4F1A620EAB34F38; Path=/
        Set-Cookie: ip_isocode=US
        Set-Cookie: clientlanguage_nl=en_EN; Expires=Thu, 07-Apr-2011 21:21:34 GMT; Path=/
2011-04-06 14:49:50-0300 [diningcity] DEBUG: Crawled (200) <GET http://www.diningcity.com/netherlands/index.html> (referer: None)
[...]

pipelines

当根据配置文件：
    ITEM_PIPELINES = {
       'xiangmu.pipelines.FilePipeline': 300,
       'xiangmu.pipelines.DBPipeline': 301,
    }
找到相关的类：FilePipeline之后，会优先判断类中是否含有 from_crawler
    如果有：
        obj = FilePipeline.from_crawler()
    没有则：
        obj = FilePipeline()
 
    obj.open_spider(..)
    ob.process_item(..)
    obj.close_spider(..）

class FilePipeline(object):
    def __init__(self,path):
        self.path = path
        self.f = None
 
    @classmethod
    def from_crawler(cls, crawler):
        """
        初始化时候，用于创建pipeline对象
        :param crawler:
        :return:
        """
        # return cls()
 
        path = crawler.settings.get('XL_FILE_PATH')
        return cls(path)
 
    def process_item(self, item, spider):
        self.f.write(item['href']+'\n')
        return item
        # 表示将item丢弃，不会被后续pipeline处理
        # raise DropItem()
 
    def open_spider(self, spider):
        """
        爬虫开始执行时，调用
        :param spider:
        :return:
        """
        self.f = open(self.path,'w')
 
    def close_spider(self, spider):
        """
        爬虫关闭时，被调用
        :param spider:
        :return:
        """
        self.f.close()
        

自定义文件pipline

class DBPipeline():
 
    def __init__(self,conn):
        self.conn = conn
 
    @classmethod
    def from_crawler(cls,crawler):
        import pymysql
        conn = pymysql.connect(host='127.0.0.1',password='',port=3306,db='s10',user='root',charset='utf8')
        # pool = crawler.settings.get('MYSQLPOOL')
        return cls(conn)
 
    def process_item(self,item,spider):
        print(item['href'],item['text'])
        self.cursor.execute('insert into url (url,title) VALUES (%s,%s)',(item['href'],item['text']))
 
        return item
    def open_spider(self,spider):
        self.cursor = self.conn.cursor()
    def close_spider(self,spider):
        self.conn.commit()
        self.conn.close()

自定义数据库piplines

去重DupeFilter

在scrapy 中是有个默认去重的

如果想自定义去重需要在setting

DUPEFILTER_CLASS = 'pachong.dupefilter.MyDupeFilter'

from scrapy.dupefilter import BaseDupeFilter
from  scrapy.utils.request import request_fingerprint
class MyDupeFilter(BaseDupeFilter):
 
    def __init__(self, path=None, debug=False):
        self.record = set()
 
    @classmethod
    def from_settings(cls, settings):
 
        return cls()
 
    def request_seen(self, request):
        fingerprint = request_fingerprint(request)
        if fingerprint in self.record:
            print('已经访问过')
            return True
        else:
            self.record.add(fingerprint)
 
    def request_fingerprint(self, request):
        pass
 
    def close(self, reason):
 
        pass

自定义去重

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

下载器中间件

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

下载中间件

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

其他参数