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抓取廖雪峰的Git教程

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电梯直达

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发表于 2013-10-6 15:05:52 |只看该作者 |倒序浏览

本帖最后由跑跑慢慢于 2013-10-6 15:08 编辑

为了练习抓取网页内容和正则表达式而写,貌似实际没什么用处. 欢迎指点可以优化的地方.
主要步骤:
1.访问教程首页:http://www.liaoxuefeng.com/wiki/ ... 8c67b8067c8c017b000,保存至本地.
2.首页中js,css保存至本地.
3.获得各章节地址列表,依次抓取.
4.对所有网页,抓取图片并保存至本地,修改js,css以及图片地址,修改章节地址.并保存到本地.
大致这些内容.

代码:

#!/usr/bin/env python 2.7
#-*- coding:utf-8 -*-
"""
爬虫：爬廖雪峰的Git教程
请先确保 e:/git/目录存在.
import getgit 后,getgit.start()即可完成.
python 正则表达式参考:http://www.cnblogs.com/huxi/archive/2010/07/04/1771073.html
"""
import urllib2
import urllib
import re
import os
__all__=['gethtml','start','getcss','getjs','getimage']
starturl='http://www.liaoxuefeng.com/wiki/0013739516305929606dd18361248578c67b8067c8c017b000'
domain='http://www.liaoxuefeng.com/wiki/'
rootPath='e:/git/' #本地保存文件夹.
def func(m):
"""
/wiki/a/b
替换为
a.b.html
或
/wiki/a
替换为
a
"""
if(m.group(2)!=''):
s = m.group(1)+'.'+m.group(2)+'.html'
else:
s= m.group(1)+'.html'
return s
def gethtml(url):
"""
获取网页内容,并保存到本地.返回内容.
"""
print("URL:\t%s" % url)
try:
urlfile = urllib2.urlopen(url)
source = urlfile.read()
urlfile.close()
#html = source.decode('utf-8')
return source
except urllib2.HTTPError, exc:
if exc.code == 404:
print "Not found !"
else:
print "HTTP request failed with error %d (%s)" % (exc.code, exc.msg)
except urllib2.URLError, exc:
print "Failed because:", exc.reason
def start():
"""
抓取首页内容,查找地址列表,循环地址列表抓取内容.
"""
source=gethtml(starturl)
#css,js文件保存到本地.
getcss()
getjs()
#获取匹配的url列表,为各章节地址.
pattern=re.compile(r'/wiki/(\w*[/]?\w*)')
urls=re.findall(pattern,source)
#将url中 / 改为.准备工作
filenamepattern=re.compile(r'(/)')
#章节目录改为本地文件名
menupattern=re.compile(r'/wiki/(\w*)/?(\w*)')
#href="/themes/改为href="e:/git/themes/,e:/git/ 用rootPath
cssjspattern=re.compile(r'href="/(themes/)')
#<img src="/api" 替换为<img src="e:/git/api".
imagepattern=re.compile(r'<img src="/(api/.*?)/url')
getimage(source)
for url in urls:
source = gethtml(domain+url)
getimage(source)
#将url中 / 改为.
name=filenamepattern.sub(r'.',url)
#修改页面内章节目录连接.
source=menupattern.sub(func,source)
#修改css/js连接.
source=cssjspattern.sub(r'href="%s\g<1>'% rootPath,source)
#修改图片链接.
source=imagepattern.sub(r'<img src="%s\g<1>.png' % rootPath,source)
#保存本地
file=open(rootPath+name+'.html','w')
file.write(source)
file.close()
def getcss():
"""
css文件保存到本地.
"""
source=gethtml(starturl)
cssPattern = re.compile(r'(/themes.*?\.css)')
csses=re.findall(cssPattern,source)
for css in csses:
csshref = cssPattern.sub(r'http://www.liaoxuefeng.com\g<1>',css)
source = gethtml(csshref)
if source:
csspath = rootPath+css
parentfolder = os.path.split(csspath)
try:
os.makedirs(parentfolder[0])
except (WindowsError):
pass
file = open(csspath,'w')
file.write(source)
file.close()
def getjs():
"""
js文件保存到本地.
"""
source=gethtml(starturl)
cssPattern = re.compile(r'(/themes.*?\.js)')
csses=re.findall(cssPattern,source)
for css in csses:
csshref = cssPattern.sub(r'http://www.liaoxuefeng.com\g<1>',css)
source = gethtml(csshref)
if source:
csspath = rootPath+css
parentfolder = os.path.split(csspath)
try:
os.makedirs(parentfolder[0])
except (WindowsError):
pass
file = open(csspath,'w')
file.write(source)
file.close()
def getimage(source):
"""
图片下载使用urllib.urlretrieve(url,path)
源代码:src="/api/resources/001374713236987f0e694e1a02a4a538eaab311bb26a0bb000/url"
实际请求 url: http://www.liaoxuefeng.com/api/resources/001374713236987f0e694e1a02a4a538eaab311bb26a0bb000/url
保存本地位置 path: e:/git/api/resources/001374713236987f0e694e1a02a4a538eaab311bb26a0bb000.png
"""
pattern = re.compile(r'(api/.*?)(?=/url)')
resources=re.findall(pattern,source)
for resource in resources:
resourcehref = pattern.sub(r'http://www.liaoxuefeng.com/\g<1>',resource+'/url')
resourcepath = rootPath+resource+".png"
parentfolder = os.path.split(resourcepath)
try:
os.makedirs(parentfolder[0])
except (WindowsError):
pass
print("URL:\t%s" % resourcehref)
urllib.urlretrieve(resourcehref,resourcepath)
#start()