python - 为什么我直接用requests爬网页可以，但用scrapy不行？

问题描述

class job51(): def __init__(self):self.headers={ ’Accept’: ’text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8’, ’Accept-Encoding’:’gzip, deflate, sdch’, ’Accept-Language’: ’zh-CN,zh;q=0.8’, ’Cache-Control’: ’max-age=0’, ’User-Agent’:’Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.71 Safari/537.36’, ’Cookie’:’’} def start(self):html=session.get('http://my.51job.com/cv/CResume/CV_CResumeManage.php',headers=self.headers)self.parse(html) def parse(self,response):tree=lxml.etree.HTML(response.text)resume_url=tree.xpath(’//tbody/tr[@class='resumeName']/td[1]/a/@href’)print (resume_url[0]

能爬到我想要的结果，就是简历的url,但是用scrapy,同样的headers,页面好像停留在登录页面？

class job51(Spider): name = 'job51' #allowed_domains = ['my.51job.com'] start_urls = ['http://my.51job.com/cv/CResume/CV_CResumeManage.php'] headers={ ’Accept’: ’text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8’, ’Accept-Encoding’:’gzip, deflate, sdch’, ’Accept-Language’: ’zh-CN,zh;q=0.8’, ’Cache-Control’: ’max-age=0’, ’User-Agent’:’Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.71 Safari/537.36’, ’Cookie’:’’} def start_requests(self):yield Request(url=self.start_urls[0],headers=self.headers,callback=self.parse) def parse(self,response):#tree=lxml.etree.HTML(text)selector=Selector(response)print ('<<<<<<<<<<<<<<<<<<<<<',response.text)resume_url=selector.xpath(’//tr[@class='resumeName']/td[1]/a/@href’)print ('>>>>>>>>>>>>',resume_url)

输出的结果：

scrapy.utils.log] INFO: Overridden settings: {’BOT_NAME’: ’job51’, ’SPIDER_MODULES’: [’job51.spiders’], ’ROBOTSTXT_OBEY’: True, ’NEWSPIDER_MODULE’: ’job51.spiders’}2017-04-11 10:58:31 [scrapy.middleware] INFO: Enabled extensions:[’scrapy.extensions.logstats.LogStats’, ’scrapy.extensions.corestats.CoreStats’, ’scrapy.extensions.telnet.TelnetConsole’]2017-04-11 10:58:32 [scrapy.middleware] INFO: Enabled downloader middlewares:[’scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware’, ’scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware’, ’scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware’, ’scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware’, ’scrapy.downloadermiddlewares.useragent.UserAgentMiddleware’, ’scrapy.downloadermiddlewares.retry.RetryMiddleware’, ’scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware’, ’scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware’, ’scrapy.downloadermiddlewares.redirect.RedirectMiddleware’, ’scrapy.downloadermiddlewares.cookies.CookiesMiddleware’, ’scrapy.downloadermiddlewares.stats.DownloaderStats’]2017-04-11 10:58:32 [scrapy.middleware] INFO: Enabled spider middlewares:[’scrapy.spidermiddlewares.httperror.HttpErrorMiddleware’, ’scrapy.spidermiddlewares.offsite.OffsiteMiddleware’, ’scrapy.spidermiddlewares.referer.RefererMiddleware’, ’scrapy.spidermiddlewares.urllength.UrlLengthMiddleware’, ’scrapy.spidermiddlewares.depth.DepthMiddleware’]2017-04-11 10:58:32 [scrapy.middleware] INFO: Enabled item pipelines:[]2017-04-11 10:58:32 [scrapy.core.engine] INFO: Spider opened2017-04-11 10:58:32 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)2017-04-11 10:58:32 [scrapy.extensions.telnet] DEBUG: Telnet console listening on 127.0.0.1:60232017-04-11 10:58:33 [scrapy.core.engine] DEBUG: Crawled (404) <GET http://my.51job.com/robots.txt> (referer: None)2017-04-11 10:58:33 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://my.51job.com/cv/CResume/CV_CResumeManage.php> (referer: None)<<<<<<<<<<<<<<<<<<<<< <script>window.location=’https://login.51job.com/login.php?url=http://my.51job.com%2Fcv%2FCResume%2FCV_CResumeManage.php%3F7087’;</script>>>>>>>>>>>>> []2017-04-11 10:58:33 [scrapy.core.scraper] ERROR: Spider error processing <GET http://my.51job.com/cv/CResume/CV_CResumeManage.php> (referer: None)Traceback (most recent call last): File 'd:python35libsite-packagesscrapyutilsdefer.py', line 102, in iter_errback yield next(it) File 'd:python35libsite-packagesscrapyspidermiddlewaresoffsite.py', line 29, in process_spider_output for x in result: File 'd:python35libsite-packagesscrapyspidermiddlewaresreferer.py', line 22, in <genexpr> return (_set_referer(r) for r in result or ()) File 'd:python35libsite-packagesscrapyspidermiddlewaresurllength.py', line 37, in <genexpr> return (r for r in result or () if _filter(r)) File 'd:python35libsite-packagesscrapyspidermiddlewaresdepth.py', line 58, in <genexpr> return (r for r in result or () if _filter(r)) File 'E:WorkGitRespspiderjob51job51spiders51job_resume.py', line 43, in parse yield Request(resume_url[0],headers=self.headers,callback=self.getResume) File 'd:python35libsite-packagesparselselector.py', line 58, in __getitem__ o = super(SelectorList, self).__getitem__(pos)IndexError: list index out of range2017-04-11 10:58:33 [scrapy.core.engine] INFO: Closing spider (finished)2017-04-11 10:58:33 [scrapy.statscollectors] INFO: Dumping Scrapy stats:{’downloader/request_bytes’: 628, ’downloader/request_count’: 2, ’downloader/request_method_count/GET’: 2, ’downloader/response_bytes’: 5743, ’downloader/response_count’: 2, ’downloader/response_status_count/200’: 1, ’downloader/response_status_count/404’: 1, ’finish_reason’: ’finished’, ’finish_time’: datetime.datetime(2017, 4, 11, 2, 58, 33, 275634), ’log_count/DEBUG’: 3, ’log_count/ERROR’: 1, ’log_count/INFO’: 7, ’response_received_count’: 2, ’scheduler/dequeued’: 1, ’scheduler/dequeued/memory’: 1, ’scheduler/enqueued’: 1, ’scheduler/enqueued/memory’: 1, ’spider_exceptions/IndexError’: 1, ’start_time’: datetime.datetime(2017, 4, 11, 2, 58, 32, 731603)}2017-04-11 10:58:33 [scrapy.core.engine] INFO: Spider closed (finished)

问题解答

看log是404了，你看看scrapy设定那里有没把重定向禁止了。

<script>window.location=’https://login.51job.com/login.php?url=http://my.51job.com%2Fcv%2FCResume%2FCV_CResumeManage.php%3F7087’;</script>

从这里可以看到你用scrapy写的爬虫被重定向到登陆页面了。所以会报错。建议你在用requests和用scrapy请求的时候抓一下包，看看它的响应内容，并且看看它们的request headers是不是完全相同。我怀疑可能是cookie过期了，要么scrapy可能不是这样传cookie.我对scrapy不是特别熟悉，不过看问题应该是出在cookie这块了

你用的session请求的，实际的request header估计已经戴上了cookie了，所以还是像楼上说的对比请求header吧