Scrapy框架进阶攻略：代理设置、请求优化及链家网实战项目全解析

news2024/11/16 1:01:41

scrapy框架

加代理

付费代理IP池

middlewares.py

# 代理IP池
class ProxyMiddleware(object):
    proxypool_url = 'http://127.0.0.1:5555/random'
    logger = logging.getLogger('middlewares.proxy')

    async def process_request(self, request, spider):
        async with aiohttp.ClientSession() as client:
            response = await client.get(self.proxypool_url)
            if not response.status == 200:
                return
            proxy = await response.text()
            self.logger.debug(f'set proxy {proxy}')
            request.meta['proxy'] = f'http://{proxy}'

settings.py

DOWNLOADER_MIDDLEWARES = {
    "demo.middlewares.DemoDownloaderMiddleware": 543,
    "demo.middlewares.ProxyMiddleware": 544
}

隧道代理

import base64

proxyUser = "1140169503666491392"
proxyPass = "7RmCwS8r"
proxyHost = "http-short.xiaoxiangdaili.com"
proxyPort = "10010"

proxyServer = "http://%(user)s:%(pass)s@%(host)s:%(port)s" % {
    "host": proxyHost,
    "port": proxyPort,
    "user": proxyUser,
    "pass": proxyPass
}
proxyAuth = "Basic " + base64.urlsafe_b64encode(bytes((proxyUser + ":" + proxyPass), "ascii")).decode("utf8")


# 隧道代理
class ProxyMiddleware(object):
    def process_request(self, request, spider):
        request.meta["proxy"] = proxyServer
        request.headers["Connection"] = "close"
        request.headers["Proxy-Authorization"] = proxyAuth
        # 60秒一切 变为 10秒一切
        request.headers["Proxy-Switch-Ip"] = True

重试机制

settings.py

# Retry settings
RETRY_ENABLED = False
RETRY_TIMES = 5  # 想重试几次就写几
# 下面这行可要可不要
# RETRY_HTTP_CODES = [500, 502, 503, 504, 408]

重写已有重试中间件

midderwares.py

from scrapy.downloadermiddlewares.retry import RetryMiddleware

retry.py

    def _retry(self, request, reason, spider):
        max_retry_times = request.meta.get("max_retry_times", self.max_retry_times)
        priority_adjust = request.meta.get("priority_adjust", self.priority_adjust)
        # 重试更换代理IP
        proxypool_url = 'http://127.0.0.1:5555/random'
        logger = logging.getLogger('middlewares.proxy')

        async def process_request(self, request, spider):
            async with aiohttp.ClientSession() as client:
                response = await client.get(self.proxypool_url)
                if not response.status == 200:
                    return
                proxy = await response.text()
                self.logger.debug(f'set proxy {proxy}')
                request.meta['proxy'] = f'http://{proxy}'
        request.headers['Proxy-Authorization'] = "proxyauth"
        return get_retry_request(
            request,
            reason=reason,
            spider=spider,
            max_retry_times=max_retry_times,
            priority_adjust=priority_adjust,
        )

零碎知识点

scrapy两种请求方式

GET请求

import scrapy
yield scrapy.Request(begin_url,self.first)

POST请求

from scrapy import FormRequest ##Scrapy中用作登录使用的一个包
formdata = {    'username': 'wangshang',    'password': 'a706486'}
yield scrapy.FormRequest( 
url='http://172.16.10.119:8080/bwie/login.do',
formdata=formdata,   
callback=self.after_login,
)

应用场景：POST请求并且携带加密token，我们需要伪造POST请求并且解密token

scrapy个性化配置

settings.py

custom_settings_for_centoschina_cn = {
'DOWNLOADER_MIDDLEWARES' : {
   'questions.middlewares.QuestionsDownloaderMiddleware': 543,
},
'ITEM_PIPELINES': {
   'questions.pipelines.QuestionsPipeline': 300,
},
'MYSQL_URI' : '124.221.206.17',
# 'MYSQL_URI' : '43.143.155.25',
'MYSQL_DB' : 'mydb',
'MYSQL_USER':'root',
'MYSQL_PASSWORD':'123456',

}

爬虫部分

import scrapy
from questions.settings import custom_settings_for_centoschina_cn
from questions.items import QuestionsItem
from lxml import etree
class CentoschinaCnSpider(scrapy.Spider):
    name = 'centoschina.cn'
    # allowed_domains = ['centoschina.cn']
    custom_settings = custom_settings_for_centoschina_cn

3种方式加headers

settings.py的默认headers

# 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",
}

每个请求加headers

headers = {
        'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36 Edg/127.0.0.0'
    }

    def start_requests(self):
        start_url = "https://2024.ip138.com/"
        for n in range(5):
            # dont_filter=True, 去掉框架自带相同链接去重机制
            yield scrapy.Request(start_url, self.get_info, dont_filter=True, headers=A2024Ip138Spider.headers)

下载器中间件加headers

 def process_request(self, request, spider):
        # Called for each request that goes through the downloader
        # middleware.
        # 加header
        request.headers[
            'user-agent'] = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36 Edg/127.0.0.0'
        # Must either:
        # - return None: continue processing this request
        # - or return a Response object
        # - or return a Request object
        # - or raise IgnoreRequest: process_exception() methods of
        #   installed downloader middleware will be called
        return None

优先级：3 > 2 > 1

request携带参数, response获取参数

    def start_requests(self):
        start_url = "https://2024.ip138.com/"
        for n in range(5):
            # dont_filter=True, 去掉框架自带相同链接去重机制
            yield scrapy.Request(start_url, self.get_info, dont_filter=True, headers=A2024Ip138Spider.headers,
                                 meta={'page': 1})

    def get_info(self, response):
        # print(response.text)
        print(response.meta['page'])
        ip = response.xpath('/html/body/p[1]/a[1]/text()').extract_first()
        print(ip)

链家（scrapy项目）

项目介绍：不封IP

核心代码

import scrapy


class TjLianjiaSpider(scrapy.Spider):
    name = "tj_lianjia"

    # allowed_domains = ["ffffffffff"]
    # start_urls = ["https://ffffffffff"]
    def __init__(self):
        self.page = 1

    def start_requests(self):
        start_url = 'https://tj.lianjia.com/ershoufang/pg{}/'.format(self.page)
        yield scrapy.Request(start_url, self.get_info)

    def get_info(self, response):
        lis = response.xpath('//li[@class="clear LOGVIEWDATA LOGCLICKDATA"]')
        for li in lis:
            title = li.xpath('div[1]/div[@class="title"]/a/text()').extract_first()
            totalprice = ''.join(li.xpath('div[1]/div[@class="priceInfo"]/div[1]//text()').extract())
            print(title, totalprice)
        self.page += 1
        next_href = 'https://tj.lianjia.com/ershoufang/pg{}/'.format(self.page)
        yield scrapy.Request(next_href, self.get_info)