如何使用我的网络爬虫从 URL 中使用 Python 获取正确的源代码？

Question

我正在尝试使用 python 编写一个网络爬虫。我正在使用 re 和 requests 模块。我想从第一页（这是一个论坛）获取 url，并从每个 url 获取信息。

我现在的问题是，我已经将 URL 存储在列表中。但我无法进一步获取这些 URL 的正确源代码。

这是我的代码：

import re
import requests

url = 'http://bbs.skykiwi.com/forum.php?mod=forumdisplay&fid=55&typeid=470&sortid=231&filter=typeid&pageNum=1&page=1'

sourceCode = getsourse(url) # source code of the url page
allLinksinPage = getallLinksinPage(sourceCode) #a List of the urls in current page
for eachLink in allLinksinPage:
    url = 'http://bbs.skykiwi.com/' + eachLink.encode('utf-8')
    html = getsourse(url) #THIS IS WHERE I CAN'T GET THE RIGHT SOURCE CODE


#To get the source code of current url
def getsourse(url):
    header = {'User-Agent': 'Mozilla/5.0 (compatible; MSIE 9.0; Windows  NT 10.0; WOW64; Trident/8.0; Touch)'}
    html = requests.get(url, headers=header)
    return html.text

#To get all the links in current page
def getallLinksinPage(sourceCode):
    bigClasses = re.findall('<th class="new">(.*?)</th>', sourceCode, re.S)
    allLinks = []
    for each in bigClasses:
        everylink = re.findall('</em><a href="(.*?)" onclick', each, re.S)[0]
        allLinks.append(everylink)
return allLinks

Answer 1

您在使用函数后定义函数，因此您的代码会出错。您也不应该使用 re 来解析 html，请使用像 beautifulsoup 这样的解析器，如下所示。还使用urlparse.urljoin 将基本网址加入链接，您真正想要的是 div内 anchor 标记中的 hrefs > ID 为threadlist:

import requests
from bs4 import BeautifulSoup
from urlparse import urljoin

url = 'http://bbs.skykiwi.com/forum.php?mod=forumdisplay&fid=55&typeid=470&sortid=231&filter=typeid&pageNum=1&page=1'



def getsourse(url):
    header = {'User-Agent': 'Mozilla/5.0 (compatible; MSIE 9.0; Windows  NT 10.0; WOW64; Trident/8.0; Touch)'}
    html = requests.get(url, headers=header)
    return html.content

#To get all the links in current page
def getallLinksinPage(sourceCode):
    soup = BeautifulSoup(sourceCode)
    return [a["href"] for a in soup.select("#threadlist a.xst")]



sourceCode = getsourse(url) # source code of the url page
allLinksinPage = getallLinksinPage(sourceCode) #a List of the urls in current page
for eachLink in allLinksinPage:
    url = 'http://bbs.skykiwi.com/'
    html = getsourse(urljoin(url, eachLink))
    print(html)

如果你在循环中打印urljoin(url, eachLink)，你会看到你得到了表的所有正确链接并返回了正确的源代码，下面是返回链接的sn-p：

http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3177846&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3197510&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3201399&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3170748&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3152747&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3168498&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3176639&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3203657&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3190138&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3140191&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3199154&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3156814&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3203435&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3089967&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3199384&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3173489&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231
http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3204107&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231

如果您在浏览器中访问上面的链接，您会看到它获得了正确的页面，使用您的结果中的http://bbs.skykiwi.com/forum.php?mod=viewthread&tid=3187289&extra=page%3D1%26filter%3Dtypeid%26typeid%3D470%26sortid%3D231%26typeid%3D470%26sortid%3D231，您将看到：

Sorry, specified thread does not exist or has been deleted or is being reviewed
[New Zealand day-dimensional network Community Home]

您可以清楚地看到网址的差异。如果你想让你的工作，你需要在你的正则表达式中做一个替换：

 everylink = re.findall('</em><a href="(.*?)" onclick', each.replace("&","%26"), re.S)[0]

但是真的不解析html会是一个正则表达式。