目录
scrapy框架
pipeline-itrm-shell
scrapy模拟登录
scrapy下载图片
下载中间件
scrapy框架
含义:
构图:
运行流程:1.scrapy框架拿到start_urls构造了一个request请求
request请求发送给scrapy引擎,中途路过爬虫中间件,引擎再发送request给调度器(一个队列存储request请求)
调度器再把requst请求发送给引擎
引擎再把requst请求发送给下载器,中途经过下载中间件
下载器然后访问互联网然后返回response响应
下载器把得到的response发送给引擎,中途经过下载中间件
引擎发送resonse给爬虫,中途路过爬虫中间件
爬虫通过response获取数据,(可以获取url,....)如果还想再发请求,就再构造一个request请求进行发送给引擎并再循环一次,如果不发请求,就把数据发送给引擎,中途路过爬虫中间件
引擎把数据再发送给管道
管道进行保存
我们先来通过cmd页板来创建项目吧
c:/d:/e: --->切换网盘
cd 文件名称 ----->切换进文件
scrapy startproject 项目名称 -------->创建项目
scrapy genspider 爬虫文件名称 域名 ------->创建爬虫文件
scrapy crawl 爬虫文件名称 ------------>运行爬虫文件
我们还可以创建start.py文件运行爬虫文件(要创建在项目下的第一层)
文件的创建位置:
代码运行爬虫文件:
from scrapy import cmdline# cmdline.execute("scrapy crawl baidu".split())# cmdline.execute("scrapy crawl novel".split())cmdline.execute("scrapy crawl shiping".split())导入from scrapy import cmdline
cmdline.execute([ 'scrapy',' crawl',' 爬虫文件名称' ]) :运行爬虫文件
下面我来分析一下里面的文件
爬虫名字.py文件
可以看出scrapy框架给出了一些类属性,这些类属性的值可以更改,但是def parse()是不能随意更改名字和传参的
settings.py文件
找到这个并打开,把注释去掉,数值越小越先执行,如果不打开就无法传数据到pipelines.py文件里的
MyScrapyPipeline类中的process_item()中的item参数下面我来演示,
import scrapyclass BaiduSpider(scrapy.Spider): name = 'douban' allowed_domains = ['douban.com'] start_urls = ['https://movie.douban.com/review/best/'] def parse(self, response): print(response.text)结果:
当我们点击第一个网址是会跳转到下面去
是因为爬虫文件遵守了一个规则,解决方法如下:在settings.py文件找到如下的代码:
把True改为False,然后运行
结果:
可以看出减少了一个错误
但还是有错误,下面我们来解决一下:
解决403的方法有添加UA(header请求头)
如图找到这里:
把My_scrapy (+http://www.yourdomain.com)这个更改为一个请求头:
结果:
可以正常访问了
middlewares.py文件( 用于加请求头)
但有些小可爱觉得这样太麻烦了,如果是更换header请求头很频繁就很不好用,对于这个问题,我们可以想想,如果在发送请求的过程就加个请求头是不是就不用这么麻烦了,那怎么加呢,
小可爱们可以想想,中间件这个是不是可以利用一下:
那我们就要找到中间件了,中间件在scrapy项目是一个middlewares.py文件
当我们打开这个文件是会看见:
主要是这个文件把爬虫中间件和下载中间件都写在middlewares.py文件
MyScrapyDownloaderMiddleware 这个是下载中间件MyScrapySpiderMiddleware 这个是爬虫中间件所以下面我来讲解 MyScrapyDownloaderMiddleware
主要的还是这两个比较常用,下面我们先来process_crawler
代码截图:
当我们打印的时候会发现,怎么没有打印,为什么会这样? 原因是我们的中间件还未打开,下面我们举要找到settings,py文件,并将其注释去掉
代码截图:
一运行成功了:
那我们再来试试process_response
代码截图:
结果:
可以看出request 是在response前面的
可能一些小可爱又想到了一些情况,可不可以创建一个请求和响应的呢
下面我们来试试
代码截图:
结果:
细心的小可爱会发现和自己的预想不对,
下面我截取下载中间件来:
这个就是问题所在
下面我来解释一下下面的:
process_request(request, spider)
# - return None: continue processing this request当return None时就会传递下去,比如duoban的process_request() 返回return None就会运行下载中间件的process_request()# - or return a Request object当return (一个Request对象)时不会传递下去,比如duoban的process_request() 返回return (一个Request对象)就不会运行下载中间件的process_request()而是返回到引擎,引擎返回给调度器(原路返回)# - or return a Response object当return (一个Responset对象)时不会传递下去,比如duoban的process_request() 返回return (一个Response对象)就不会运行下载中间件的process_request()而是返回到引擎,引擎返回给爬虫文件(跨级)# - or raise IgnoreRequest: process_exception() methods of如果这个⽅法抛出异常,则会调⽤process_exception⽅法 # installed downloader middleware will be calledprocess_response(request, response, spider)
# - return a Response object# - return a Request object返回Request对象：停⽌中间器调⽤，将其放置到调度器待调度下载；# - or raise IgnoreRequest有些小可爱就会想,那我可不可以自己创建一个中间件用于添加请求头:(要在middlewares.py文件)
from scrapy import signalsimport randomclass UsertMiddleware: User_Agent=["Mozilla/5.0 (compatible; MSIE 9.0; AOL 9.7; AOLBuild 4343.19; Windows NT 6.1; WOW64; Trident/5.0; FunWebProducts)", "Mozilla/4.0 (compatible; MSIE 8.0; AOL 9.7; AOLBuild 4343.27; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)"] def process_request(self, request, spider): # 添加请求头 print(dir(request)) request.headers["User-Agent"]=random.choice(self.User_Agent) # 添加代理ip # request.meta["proxies"]="代理ip" return Noneclass UafgfMiddleware: def process_response(self, request, response, spider): # 检测请求头是否添加上 print(request.headers["User-Agent"]) return response结果
是可以运行的
pipelines.py文件
process_item(self, item, spider)item:接收爬虫文件返回过来的数据,如字典
下面我们来爬取一下豆瓣吧
练习爬取豆瓣电影的图片
爬虫文件.py:
import scrapyclass BaiduSpider(scrapy.Spider): name = 'douban' allowed_domains = ['douban.com','doubanio.com'] start_urls = ['https://movie.douban.com/review/best/'] a=1 def parse(self, response): divs=response.xpath('//div[@id="content"]//div[@class="review-list chart "]//div[@class="main review-item"]') for div in divs: # print(div.extract) title=div.xpath('./a/img/@title') src=div.xpath('./a/img/@src') # print(title.extract_first()) print(src.extract_first()) yield { "title": title.extract_first(), "src": src.extract_first(), "type": "csv" } # 再发请求下载图片 yield scrapy.Request( url=src.extract_first(), callback=self.parse_url, cb_kwargs={"imgg":title.extract_first()} ) #第一种 # next1=response.xpath(f'//div[@class="paginator"]//a[1]/@href').extract_first() # 第二种方法自己构建 next1="/review/best?start={}".format(20*self.a) self.a+=1 url11='https://movie.douban.com'+next1 yield scrapy.Request(url=url11,callback=self.parse) print(url11) def parse_url(self,response,imgg): # print(response.body) yield { "title":imgg, "ts":response.body, "type":"img" }pipelines.py文件:
import csvclass MyScrapyPipeline: def open_spider(self,spider): # 当爬虫开启时调用 header = ["title", "src"] self.f = open("move.csv", "a", encoding="utf-8") self.wri_t=csv.DictWriter(self.f,header) self.wri_t.writeheader() def process_item(self, item, spider): # 每次传参都会调用一次 if item.get("type")=="csv": item.pop("type") self.wri_t.writerow(item) if item.get("type")=="img": item.pop("type") with open("./图片/{}.png".format(item.get("title")),"wb")as f: f.write(item.get("ts")) print("{}.png下载完毕".format(item.get("title"))) return item def close_spider(self,spider): self.f.close()settings.py文件:
这个可以只输出自己想输出的内容
_____________________________________
以上这些都有打开
记住如果爬虫文件里发送请求失败后就无法回调pipelines.py文件里的函数
暂停和恢复爬虫的方法
有些小可爱觉得有没有可以暂停和恢复爬虫的方法?有的话那是啥
下面我来讲讲
scrapy crawl 爬虫文件名字 -s JOBDIR=文件路径(随便定义)
Ctrl+c暂停爬虫
当小可爱想再次恢复时会发现不能运行下载了,
原因是啥呢,因为我们写的方法和框架给的不一样,
scrapy.Request如下:
dont_filte(不过滤吗?)r是一个过滤,为False则过滤(相同的url只访问一次),为True则不过滤
小可爱就会觉得那为啥parse()能发送,结果如下:
结果就很明了了,如果要想不过滤,就得更改
如果你想过滤重写方法:
scrapy模拟登录
有两种方法:
● 1 直接携带cookies请求⻚⾯(半自动,用selenium获取或者自己手动获取cookie)
● 2 找接⼝发送post请求存储cookie(发送账号和密码) 下面我用https://www.1905.com/vod/list/c_178/o3u1p1.html来做个案例
第一种方法之手动登录获取之请求页面
爬虫文件代码实例一(在爬虫文件添加cookie);
import scrapyclass A17kSpider(scrapy.Spider): name = '17k' allowed_domains = ['17k.com'] start_urls = ['https://www.17k.com/'] # 重写 def start_requests(self): cook="GUID=f0f80f5e-fb00-443f-a6be-38c6ce3d4c61; __bid_n=1883d51d69d6577cf44207; BAIDU_SSP_lcr=https://www.baidu.com/link?url=v-ynoaTMtiyBil1uTWfIiCbXMGVZKqm4MOt5_xZD0q7&wd=&eqid=da8d6ae20003f26f00000006647c3209; Hm_lvt_9793f42b498361373512340937deb2a0=1684655954,1684929837,1685860878; dfxafjs=js/dfxaf3-ef0075bd.js; FPTOKEN=zLc3s/mq2pguVT/CfivS7tOMcBA63ZrOyecsnTPMLcC/fBEIx0PuIlU5HgkDa8ETJkZYoDJOSFkTHaz1w8sSFlmsRLKFG8s+GO+kqSXuTBgG98q9LQ+EJfeSHMvwMcXHd+EzQzhAxj1L9EnJuEV2pN0w7jUCYmfORSbIqRtu5kruBMV58TagSkmIywEluK5JC6FnxCXUO0ErYyN/7awzxZqyqrFaOaVWZZbYUrhCFq0N8OQ1NMPDvUNvXNDjDOLM6AU9f+eHsXFeAaE9QunHk6DLbxOb8xHIDot4Pau4MNllrBv8cHFtm2U3PHX4f6HFkEpfZXB0yVrzbX1+oGoscbt+195MLZu478g3IFYqkrB8b42ILL4iPHtj6M/MUbPcxoD25cMZiDI1R0TSYNmRIA==|U8iJ37fGc7sL3FohNPBpgau0+kHrBi2OlH2bHfhFOPQ=|10|87db5f81d4152bd8bebb5007a0f3dbc3; c_channel=0; c_csc=web; accessToken=avatarUrl%3Dhttps%253A%252F%252Fcdn.static.17k.com%252Fuser%252Favatar%252F03%252F43%252F75%252F100257543.jpg-88x88%253Fv%253D1685860834000%26id%3D100257543%26nickname%3D%25E8%2580%2581%25E5%25A4%25A7%25E5%2592%258C%25E5%258F%258D%25E5%25AF%25B9%25E6%25B3%2595%25E7%259A%2584%25E5%258F%258D%26e%3D1701413546%26s%3Db67793dfa5cea859; sensorsdata2015jssdkcross=%7B%22distinct_id%22%3A%22100257543%22%2C%22%24device_id%22%3A%221883d51d52d1790-08af8c489ac963-26031a51-1638720-1883d51d52eea0%22%2C%22props%22%3A%7B%22%24latest_traffic_source_type%22%3A%22%E8%87%AA%E7%84%B6%E6%90%9C%E7%B4%A2%E6%B5%81%E9%87%8F%22%2C%22%24latest_referrer%22%3A%22https%3A%2F%2Fwww.baidu.com%2Flink%22%2C%22%24latest_referrer_host%22%3A%22www.baidu.com%22%2C%22%24latest_search_keyword%22%3A%22%E6%9C%AA%E5%8F%96%E5%88%B0%E5%80%BC%22%7D%2C%22first_id%22%3A%22f0f80f5e-fb00-443f-a6be-38c6ce3d4c61%22%7D; Hm_lpvt_9793f42b498361373512340937deb2a0=1685861547" yield scrapy.Request( url=self.start_urls[0], callback=self.parse, cookies={lis.split("=")[0]:lis.split("=")[1] for lis in cook.split(";")} ) def parse(self, response): # print(response.text) yield scrapy.Request(url="https://user.17k.com/www/",callback=self.parse_url) def parse_url(self,response): print(response.text)结果:
爬虫文件代码实例二(在下载中间件文件添加cookie);
class MyaddcookieMiddleware: def process_request(self, request, spider): cook = "GUID=f0f80f5e-fb00-443f-a6be-38c6ce3d4c61; __bid_n=1883d51d69d6577cf44207; BAIDU_SSP_lcr=https://www.baidu.com/link?url=v-ynoaTMtiyBil1uTWfIiCbXMGVZKqm4MOt5_xZD0q7&wd=&eqid=da8d6ae20003f26f00000006647c3209; Hm_lvt_9793f42b498361373512340937deb2a0=1684655954,1684929837,1685860878; dfxafjs=js/dfxaf3-ef0075bd.js; FPTOKEN=zLc3s/mq2pguVT/CfivS7tOMcBA63ZrOyecsnTPMLcC/fBEIx0PuIlU5HgkDa8ETJkZYoDJOSFkTHaz1w8sSFlmsRLKFG8s+GO+kqSXuTBgG98q9LQ+EJfeSHMvwMcXHd+EzQzhAxj1L9EnJuEV2pN0w7jUCYmfORSbIqRtu5kruBMV58TagSkmIywEluK5JC6FnxCXUO0ErYyN/7awzxZqyqrFaOaVWZZbYUrhCFq0N8OQ1NMPDvUNvXNDjDOLM6AU9f+eHsXFeAaE9QunHk6DLbxOb8xHIDot4Pau4MNllrBv8cHFtm2U3PHX4f6HFkEpfZXB0yVrzbX1+oGoscbt+195MLZu478g3IFYqkrB8b42ILL4iPHtj6M/MUbPcxoD25cMZiDI1R0TSYNmRIA==|U8iJ37fGc7sL3FohNPBpgau0+kHrBi2OlH2bHfhFOPQ=|10|87db5f81d4152bd8bebb5007a0f3dbc3; c_channel=0; c_csc=web; accessToken=avatarUrl%3Dhttps%253A%252F%252Fcdn.static.17k.com%252Fuser%252Favatar%252F03%252F43%252F75%252F100257543.jpg-88x88%253Fv%253D1685860834000%26id%3D100257543%26nickname%3D%25E8%2580%2581%25E5%25A4%25A7%25E5%2592%258C%25E5%258F%258D%25E5%25AF%25B9%25E6%25B3%2595%25E7%259A%2584%25E5%258F%258D%26e%3D1701413546%26s%3Db67793dfa5cea859; sensorsdata2015jssdkcross=%7B%22distinct_id%22%3A%22100257543%22%2C%22%24device_id%22%3A%221883d51d52d1790-08af8c489ac963-26031a51-1638720-1883d51d52eea0%22%2C%22props%22%3A%7B%22%24latest_traffic_source_type%22%3A%22%E8%87%AA%E7%84%B6%E6%90%9C%E7%B4%A2%E6%B5%81%E9%87%8F%22%2C%22%24latest_referrer%22%3A%22https%3A%2F%2Fwww.baidu.com%2Flink%22%2C%22%24latest_referrer_host%22%3A%22www.baidu.com%22%2C%22%24latest_search_keyword%22%3A%22%E6%9C%AA%E5%8F%96%E5%88%B0%E5%80%BC%22%7D%2C%22first_id%22%3A%22f0f80f5e-fb00-443f-a6be-38c6ce3d4c61%22%7D; Hm_lpvt_9793f42b498361373512340937deb2a0=1685861547" cookies = {lis.split("=")[0]: lis.split("=")[1] for lis in cook.split(";")} request.cookies=cookies return None爬虫文件代码实例三(在下载中间件文件添加cookie);
def sele(): #创建一个浏览器 driver=webdriver.Chrome() #打开网页 driver.get("https://user.17k.com/www/bookshelf/") print("你有15秒的时间登入") time.sleep(15) print(driver.get_cookies()) print({i.get("name"):i.get("value") for i in driver.get_cookies()})class MyaddcookieMiddleware: def process_request(self, request, spider): sele() return None找接⼝发送post请求存储cookie
代码1:
import scrapyclass A17kSpider(scrapy.Spider): name = '17k' allowed_domains = ['17k.com'] start_urls = ['https://www.17k.com/'] # # 重写 # def start_requests(self): # cook="GUID=f0f80f5e-fb00-443f-a6be-38c6ce3d4c61; __bid_n=1883d51d69d6577cf44207; BAIDU_SSP_lcr=https://www.baidu.com/link?url=v-ynoaTMtiyBil1uTWfIiCbXMGVZKqm4MOt5_xZD0q7&wd=&eqid=da8d6ae20003f26f00000006647c3209; Hm_lvt_9793f42b498361373512340937deb2a0=1684655954,1684929837,1685860878; dfxafjs=js/dfxaf3-ef0075bd.js; FPTOKEN=zLc3s/mq2pguVT/CfivS7tOMcBA63ZrOyecsnTPMLcC/fBEIx0PuIlU5HgkDa8ETJkZYoDJOSFkTHaz1w8sSFlmsRLKFG8s+GO+kqSXuTBgG98q9LQ+EJfeSHMvwMcXHd+EzQzhAxj1L9EnJuEV2pN0w7jUCYmfORSbIqRtu5kruBMV58TagSkmIywEluK5JC6FnxCXUO0ErYyN/7awzxZqyqrFaOaVWZZbYUrhCFq0N8OQ1NMPDvUNvXNDjDOLM6AU9f+eHsXFeAaE9QunHk6DLbxOb8xHIDot4Pau4MNllrBv8cHFtm2U3PHX4f6HFkEpfZXB0yVrzbX1+oGoscbt+195MLZu478g3IFYqkrB8b42ILL4iPHtj6M/MUbPcxoD25cMZiDI1R0TSYNmRIA==|U8iJ37fGc7sL3FohNPBpgau0+kHrBi2OlH2bHfhFOPQ=|10|87db5f81d4152bd8bebb5007a0f3dbc3; c_channel=0; c_csc=web; accessToken=avatarUrl%3Dhttps%253A%252F%252Fcdn.static.17k.com%252Fuser%252Favatar%252F03%252F43%252F75%252F100257543.jpg-88x88%253Fv%253D1685860834000%26id%3D100257543%26nickname%3D%25E8%2580%2581%25E5%25A4%25A7%25E5%2592%258C%25E5%258F%258D%25E5%25AF%25B9%25E6%25B3%2595%25E7%259A%2584%25E5%258F%258D%26e%3D1701413546%26s%3Db67793dfa5cea859; sensorsdata2015jssdkcross=%7B%22distinct_id%22%3A%22100257543%22%2C%22%24device_id%22%3A%221883d51d52d1790-08af8c489ac963-26031a51-1638720-1883d51d52eea0%22%2C%22props%22%3A%7B%22%24latest_traffic_source_type%22%3A%22%E8%87%AA%E7%84%B6%E6%90%9C%E7%B4%A2%E6%B5%81%E9%87%8F%22%2C%22%24latest_referrer%22%3A%22https%3A%2F%2Fwww.baidu.com%2Flink%22%2C%22%24latest_referrer_host%22%3A%22www.baidu.com%22%2C%22%24latest_search_keyword%22%3A%22%E6%9C%AA%E5%8F%96%E5%88%B0%E5%80%BC%22%7D%2C%22first_id%22%3A%22f0f80f5e-fb00-443f-a6be-38c6ce3d4c61%22%7D; Hm_lpvt_9793f42b498361373512340937deb2a0=1685861547" # yield scrapy.Request( # url=self.start_urls[0], # callback=self.parse, # cookies={lis.split("=")[0]:lis.split("=")[1] for lis in cook.split(";")} # ) # # def parse(self, response): # # print(response.text) # # yield scrapy.Request(url="https://user.17k.com/www/bookshelf/",callback=self.parse_url) # pass # def parse_url(self,response): # # # print(response.text) # pass #发送post请求 def parse(self, response): data={ "loginName": "15278307585", "password": "wasd1234"} yield scrapy.FormRequest( url="https://passport.17k.com/ck/user/login", callback=self.prase_url, formdata=data ) #适用于该页面有form表单 # yield scrapy.FormRequest.from_response(response,formdata=data,callback=self.start_urls) def prase_url(self,response): print(response.text)除了这些还可以通过下载中间件返回respose对象来
from scrapy import signalsfrom selenium import webdriverfrom selenium.webdriver.common.by import Byfrom selenium.webdriver.common.action_chains import ActionChainsimport timefrom scrapy.http.response.html import HtmlResponselass MyaaacookieMiddleware: def process_request(self, request, spider): # 创建一个浏览器 driver=webdriver.Chrome() # 打开浏览器 driver.get("https://juejin.cn/") driver.implicitly_wait(3) # js语句下拉 for i in range(3): driver.execute_script("window.scrollTo(0, document.body.scrollHeight)") time.sleep(3) html=driver.page_source return HtmlResponse(url=driver.current_url,body=html,request=request,encoding="utf-8")以上就是这些内容了.
总结
scrapy框架就是为了解决我们爬取许多数据而造成大量的代码重写,通过少数代码解决问题
来源地址：https://blog.csdn.net/m0_69984273/article/details/130998544
