第13章 Python的HTML应用

本章的知识点：

1、HTML的标签；
2、URL的处理，包含解析、拼合和分解等；
3、URL的编解吗；
4、urllib模块的使用；

内容：

13.1 HTML介绍

13.1.1 HTML的历史

13.1.2 SGML、HTML、XHTML、HTML5的关系

13.1.3 HTML的标签

13.1.4 HTML的框架组件

13.2 URL的处理

13.2.1 统一资源定位符UR

表 13-1 常用的协议
协议名称 协议含义 协议名称 协议含义
 http  超文本传送协议  mailto  电子邮件
 https  使用安全套接层的超文本传送协议  file  本地计算机上的文件
 ftp  文件传输协议  telnet  Telnt协议

 

 

 

 

 

 

13.2.2 URL的解析

表 13-2 urlparse方法返回对象中的属性
属    性 索引值 值 如果不包含的值 属     性 索引值 值 如果不包含的值
scheme 0 协议 空字符串 fragment 5 分片部分 空字符串
netloc 1 服务器地址 空字符串 username   用户名 None
path 2 路径 空字符串 password   密码 None
params 3 参数 空字符串 hostname   主机名 None
query 4 查询部分 空字符串 port   端口 None 
1 from urllib.parse import urlparse
2 r = urlparse('http://alice:secret@www.hostname.com:80/%7Ealice/python.cgi?query=text#sample')
3 print (r)
4 # 输出：ParseResult(scheme='http', netloc='alice:secret@www.hostname.com:80', path='/%7Ealice/python.cgi', params='', query='query=text', fragment='sample')
View Code
 1 from urllib.parse import urlparse
 2 r = urlparse('http://alice:secret@www.hostname.com:80/%7Ealice/python.cgi?query=text#sample')
 3 print (r)
 4 print (r.scheme)
 5 print (r.netloc)
 6 print (r.path)
 7 print (r.params)
 8 print (r.query)
 9 print (r.fragment)
10 print (r.username)
11 print (r.password)
12 print (r.hostname)
13 print (r.port)
14 print (r.geturl())
15 r2 = urlparse("www.python.org/about","http")
16 print (r2)
17 # 输出：ParseResult(scheme='http', netloc='alice:secret@www.hostname.com:80', path='/%7Ealice/python.cgi', params='', query='query=text', fragment='sample')
18 # http
19 # alice:secret@www.hostname.com:80
20 # /%7Ealice/python.cgi
21 # 
22 # query=text
23 # sample
24 # alice
25 # secret
26 # www.hostname.com
27 # 80
28 # http://alice:secret@www.hostname.com:80/%7Ealice/python.cgi?query=text#sample
29 # ParseResult(scheme='http', netloc='', path='www.python.org/about', params='', query='', fragment='')
View Code

13.2.3 URL的拼合

1 from urllib.parse import urljoin,urlsplit,urlunsplit
2 r = urljoin("http://www.zeroc.com", "ice.html")
3 print (r)
4 r2 = urljoin("","")
5 print (r2)
6 # 输出：http://www.zeroc.com/ice.html
View Code
 1 from urllib.parse import urljoin,urlsplit,urlunsplit
 2 r = urljoin("http://www.zeroc.com", "ftp://www.zeroc.com/ftp")
 3 print (r)
 4 r2 = urljoin("http://www.zeroc.com", "www.zeroc.com/ftp")
 5 print (r2)
 6 r3 = urljoin("http://www.zeroc.com", "http://www.zeroc.com/ftp")
 7 print (r3)
 8 # 输出：ftp://www.zeroc.com/ftp
 9 # http://www.zeroc.com/www.zeroc.com/ftp
10 # http://www.zeroc.com/ftp
View Code

 13.2.4 URL的分析

1 r = urlsplit("http://www.python.org:80/faq.cgi?src=fie")
2 print (r)
View Code
1 r = urlsplit("http://www.python.org:80/faq.cgi?src=fie")
2 print (r)
3 
4 r = urlunsplit("http", "www.python.org", "faq", "", "")
5 print (r)
6 
7 r = urlunsplit(urlsplit("http://www.python.org/faq"))
8 print (r)
View Code
 1 from urllib.parse import urlparse,urljoin,urlunsplit
 2 abs_urls = ["http://www.python.org", "ftp://www.linux.org", "http://www.gtk.org", "file://"]
 3 rel_url = "faq.html"
 4 for abs_url in abs_urls:
 5     url = urljoin(abs_url, rel_url)
 6     expected_url = url
 7     scheme, netloc, path, query, fragment = urlsplit(url)
 8     if scheme or scheme == "file":
 9         print (url, "====> None")
10         continue
11     if scheme is not "ftp":
12         expected_url = urlunsplit(('http', netloc, path, query, fragment))
13     print (url, "====>", expected_url)
View Code

13.2.5 URL的编解码

表 13-3  URL编码中保留的字符
保留字符 URL 编码 保留字符 URL 编码 保留字符 URL 编码
； %3B : %3A = %3D
/ %2F @ %40 & %26
？ %3F        

 

 

 

 

 

 

 

表 13-4  URL编码中不安全的字符
保留字符 URL 编码 保留字符 URL 编码 保留字符 URL 编码
< %3C { %7B   %7E
> %3E } %7D [ %5B
" %22 | %7C ] %5D
# %23 \ %5C ' %60
% %25 ^ %5E    

 

 

 

 

 

 

 

表 13-5  urllib.parse 模块中 URL 编解码方法
方法 功能 方法 功能
quote 对URL进行编码 unquote 对URL进行解码
quote_plus 同quote方法，进一步将空格表示成+符合 unquote_plus 同unquote方法，进一步将+符合变成空格

13.2.5 URL的编解码

 1 from urllib.parse import quote,quote_plus, unquote, unquote_plus
 2 r1 = quote("/-test")
 3 print (r1)
 4 r2 = quote("/-test/public html")
 5 print (r2)
 6 r3 = quote_plus("/-test/public html")
 7 print (r3)
 8 unquote_plus(r3)
 9 unquote_plus(r2)
10 r = quote("/-test", "-/")
11 # 输出：/-test
12 # /-test/public%20html
13 # %2F-test%2Fpublic+html
View Code

13.2.6 中文的编解码

1 quote("URL编码")
2 r = quote("URL编码")
3 unquote(r)
4 print (unquote(r))
View Code

13.2.7 查询参数的编码

 1 from urllib.parse import *
 2 urlencode([('keyword1', 'value1'), ('keyword2', 'value2')])
 3 urlencode()
 4 urlencode({'keyword1':'value1', 'keyword2':'value2'})
 5 a = {'keyword1':'value1', 'keyword2':'value2'}
 6 b = {'keyword2':'value2', 'keyword1':'value1'}
 7 a is b
 8 a == b
 9 urlencode([('keyword1',('value1', 'value2','value12') )])
10 urllib.urlencode([('keyword1',('value1', 'value2','value12') )], True)
11 r = urlencode([('keyword1',('value1', 'value2','value12') )])
12 unquote_plus(r)
View Code

13.3 CGL的使用

13.3.1 CGL介绍

表 13-6  HTTP支持的MIME类型
类型 子类型 说明 类型 子类型 说明
Application Octet-stream MIME编码的二进制数据 Multipart Mixed digest 混合类型，可以支持等操作文件上传
Audio Basic 音频文件 Text Html、Plain HTML文档，纯文本文档
Image Gif、Jpeg 图文文件 Video mpeg 视频文件
Message External-body 对信息的封装   
 1 print ("Content-Type:text/html")
 2 print ()
 3 print ("Content-Type:text/html\n\n")
 4 print ('<!DOCTYPE html">')
 5 print ('<html>')
 6 print ('<head>')
 7 print ('<br>&copy;2009')
 8 print ('</body>')
 9 print ('<html>')
10 # 输出：Content-Type:text/html
11 # 
12 # Content-Type:text/html
13 # 
14 # 
15 # <!DOCTYPE html">
16 # <html>
17 # <head>
18 # <br>&copy;2009
19 # </body>
20 # <html>
View Code

13.3.2 获取CGL环境信息

1 #！E：/Python3/python.exe
2 print ("Content-Type:text/html\n\n")
3 import datetime
4 print (datetime.datetime.now())
5 #输出：Content-Type:text/html
6 # 
7 # 
8 # 2019-01-06 18:00:37.908176
View Code
1 #！E：/Python3/python.exe
2 import os
3 print ("Content-Type:text/html\n\n")
4 remote_addr = os.environ['REMOTE_ADDR']
5 if remote_addr == '127.0.0.1':
6     print ("来自本地的访问")
7 else:
8     print ("来自外部的访问")
View Code
 1 #！E：/Python3/python.exe
 2 print ("Content-Type:text/html\n\n")
 3 import cgi
 4 cgi.print_environ()
 5 # 输出：Content-Type:text/html
 6 # 
 7 # 
 8 # 
 9 # <H3>Shell Environment:</H3>
10 # <DL>
11 # <DT> ALLUSERSPROFILE <DD> C:\ProgramData
12 # <DT> APPDATA <DD> C:\Users\刘永峰\AppData\Roaming
13 # <DT> COMMONPROGRAMFILES <DD> C:\Program Files\Common Files
14 # <DT> COMMONPROGRAMFILES(X86) <DD> C:\Program Files (x86)\Common Files
15 # <DT> COMMONPROGRAMW6432 <DD> C:\Program Files\Common Files
16 # <DT> COMPUTERNAME <DD> LAPTOP-PJ9B1NQR
17 # <DT> COMSPEC <DD> C:\windows\system32\cmd.exe
18 # <DT> CONFIGSETROOT <DD> C:\windows\ConfigSetRoot
19 # <DT> DRIVERDATA <DD> C:\Windows\System32\Drivers\DriverData
20 # <DT> FPS_BROWSER_APP_PROFILE_STRING <DD> Internet Explorer
21 # <DT> FPS_BROWSER_USER_PROFILE_STRING <DD> Default
22 # <DT> HOMEDRIVE <DD> C:
23 # <DT> HOMEPATH <DD> \Users\刘永峰
24 # <DT> LOCALAPPDATA <DD> C:\Users\刘永峰\AppData\Local
25 # <DT> LOGONSERVER <DD> \\LAPTOP-PJ9B1NQR
26 # <DT> NUMBER_OF_PROCESSORS <DD> 4
27 # <DT> ONEDRIVE <DD> C:\Users\刘永峰\OneDrive
28 # <DT> ONEDRIVECONSUMER <DD> C:\Users\刘永峰\OneDrive
29 # <DT> OS <DD> Windows_NT
30 # <DT> PATH <DD> F:\Anaconda3\Library\bin;F:\Anaconda3\DLLs;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\iCLS\;C:\Program Files\Intel\Intel(R) Management Engine Components\iCLS\;C:\windows\system32;C:\windows;C:\windows\System32\Wbem;C:\windows\System32\WindowsPowerShell\v1.0\;C:\windows\System32\OpenSSH\;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\Intel(R) Management Engine Components\IPT;F:\Python35\Scripts;C:\Users\刘永峰\AppData\Local\Microsoft\WindowsApps;
31 # <DT> PATHEXT <DD> .COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC
32 # <DT> PROCESSOR_ARCHITECTURE <DD> AMD64
33 # <DT> PROCESSOR_IDENTIFIER <DD> Intel64 Family 6 Model 92 Stepping 9, GenuineIntel
34 # <DT> PROCESSOR_LEVEL <DD> 6
35 # <DT> PROCESSOR_REVISION <DD> 5c09
36 # <DT> PROGRAMDATA <DD> C:\ProgramData
37 # <DT> PROGRAMFILES <DD> C:\Program Files
38 # <DT> PROGRAMFILES(X86) <DD> C:\Program Files (x86)
39 # <DT> PROGRAMW6432 <DD> C:\Program Files
40 # <DT> PSMODULEPATH <DD> C:\Program Files\WindowsPowerShell\Modules;C:\windows\system32\WindowsPowerShell\v1.0\Modules
41 # <DT> PUBLIC <DD> C:\Users\Public
42 # <DT> PYCHARM_HOSTED <DD> 1
43 # <DT> PYCHARM_MATPLOTLIB_PORT <DD> 50202
44 # <DT> PYTHONIOENCODING <DD> UTF-8
45 # <DT> PYTHONPATH <DD> C:\PyCharm 2017.3.3\helpers\pycharm_matplotlib_backend;D:\Python\零基础学 python
46 # <DT> PYTHONUNBUFFERED <DD> 1
47 # <DT> SESSIONNAME <DD> Console
48 # <DT> SYSTEMDRIVE <DD> C:
49 # <DT> SYSTEMROOT <DD> C:\windows
50 # <DT> TEMP <DD> C:\Users\刘永峰\AppData\Local\Temp
51 # <DT> TMP <DD> C:\Users\刘永峰\AppData\Local\Temp
52 # <DT> USERDOMAIN <DD> LAPTOP-PJ9B1NQR
53 # <DT> USERDOMAIN_ROAMINGPROFILE <DD> LAPTOP-PJ9B1NQR
54 # <DT> USERNAME <DD> 刘永峰
55 # <DT> USERPROFILE <DD> C:\Users\刘永峰
56 # <DT> WINDIR <DD> C:\windows
57 # </DL>
View Code
表 13-7  CGL 中的部分环境变量
环境变量 含   义 环境变量 含   义
REMOTE_ADDR 服务器的地址 SCRIPT_NAME 服务器执行脚本名字
PATH_INFO 路径信息 HTTP_USER_AGENT 客户端软件
REQUEST_METHOD 客户端请求的方法，可以为GET或POST SERVER_PROTOCOL 服务器支持协议
SERVER_NAME 服务器名字 SERVER_SOFTWARE 服务器端软件信息
SERVER_PORT 服务器端口 QUERY_STRING 查询字符串

13.3.3 解析用户的输入

1 #！E：/Python3/python.exe
2 print ("Content-Type:text/html\n\n")
3 import cgi
4 form = cgi.FieldStorage()
5 for key in form.keys():
6     print (key, "==>", form[key].value)
7     print ("<br/>")
View Code
1 #！E：/Python3/python.exe
2 print ("Content-Type:text/html\n\n")
3 import cgi
4 form = cgi.FieldStorage()
5 for key in form.keys():
6     print (key, "==>", form.getlist(key))
7     print ("<br/>")
View Code
1 #！E：/Python3/python.exe
2 print ("Content-Type:text/html\n\n")
3 import cgi
4 form = cgi.FieldStorage()
5 for key in form.keys():
6     for value in form.getlist(key):
7         print (key, "==>", cgi.escape(value))
8         print ("<br/>")
View Code

13.4 获取HTML资源

13.4.1 使用urlopen和urlretrieve获取HTTP资源

 1 from urllib.request import urlopen
 2 r = urlopen("http://www.python.org")
 3 print (r.read())
 4 # 输出：b'<!doctype html>\n<!--[if lt IE 7]>  
 5 #  <html class="no-js ie6 lt-ie7 lt-ie8 lt-ie9">  
 6 #  <![endif]-->\n<!--[if IE 7]>     
 7 #  <html class="no-js ie7 lt-ie8 lt-ie9">         
 8 #  <![endif]-->\n<!--[if IE 8]>      
 9 # <html class="no-js ie8 lt-ie9">               
10 #   <![endif]-->\n<!--[if gt IE 8]><!--><html class="no-js" lang="en" dir="ltr">
11 #   <!--<![endif]-->\n\n<head>\n    
12 # <meta charset="utf-8">\n    
13 # <meta http-equiv="X-UA-Compatible" content="IE=edge">\n\n    
14 # <link rel="prefetch" href="//ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js">\n\n  
15 #   <meta name="application-name" content="Python.org">\n    
16 # <meta name="msapplication-tooltip" content="The official home of the 
17 # Python Programming Language">\n    <meta name="apple-mobile-web-app-title"
18 #  content="Python.org">\n    <meta name="apple-mobile-web-app-capable" content="yes">\n  
19 #   <meta name="apple-mobile-web-app-status-bar-style" content="black">\n\n   
20 #  <meta name="viewport" content="width=device-width, initial-scale=1.0">\n   
21 #  <meta name="HandheldFriendly" content="True">\n    
22 # <meta name="format-detection" content="telephone=no">\n    
23 # <meta http-equiv="cleartype" content="on">\n    
24 # <meta http-equiv="imagetoolbar" content="false">\n\n    
25 # <script src="/static/js/libs/modernizr.js"></script>\n\n  
26 #   <link href="/static/stylesheets/style.css" rel="stylesheet" 
27 # type="text/css" title="default" />\n   
28 #  <link href="/static/stylesheets/mq.css" rel="stylesheet" 
29 # type="text/css" media="not print, braille, embossed, speech, tty" />\n   
30 #  \n\n    <!--[if (lte IE 8)&(!IEMobile)]>\n   
31 #  <link href="/static/stylesheets/no-mq.css"
32 #  rel="stylesheet" type="text/css" media="screen" />\n    \n  
33 #   \n    <![endif]-->\n\n    \n    
34 # <link rel="icon" type="image/x-icon" href="/static/favicon.ico">\n    
35 # <link rel="apple-touch-icon-precomposed" sizes="144x144" 
36 # href="/static/apple-touch-icon-144x144-precomposed.png">\n    
37 # <link rel="apple-touch-icon-precomposed" sizes="114x114"
38 #  href="/static/apple-touch-icon-114x114-precomposed.png">\n   
39 #  <link rel="apple-touch-icon-precomposed" 
40 # sizes="72x72" href="/static/apple-touch-icon-72x72-precomposed.png">\n   
41 #  <link rel="apple-touch-icon-precomposed" href="/static/apple-touch-icon-precomposed.png">\n 
42 #    <link rel="apple-touch-icon" href="/static/apple-touch-icon-precomposed.png">\n\n 
43 #    \n    <meta name="msapplication-TileImage"
44 #  content="/static/metro-icon-144x144-precomposed.png"><!-- white shape -->\n   
45 #  <meta name="msapplication-TileColor" content="#3673a5"><!-- python blue -->\n   
46 #  <meta name="msapplication-navbutton-color" content="#3673a5">\n\n   
47 #  <title>Welcome to Python.org</title>\n\n   
48 #  <meta name="description" content="The official home of the Python Programming Language">\n 
49 #    <meta name="keywords" content="Python programming language object
50 #  oriented web free open source software license documentation download community">\n\n  
51 #   \n    <meta property="og:type" content="website">\n   
52 #  <meta property="og:site_name" content="Python.org">\n    
53 # <meta property="og:title" content="Welcome to Python.org">\n  
54 #   <meta property="og:description" content="The official home of the Python 
55 # Programming Language">\n    \n    <meta property="og:image" 
56 # content="https://www.python.org/static/opengraph-icon-200x200.png">\n   
57 #  <meta property="og:image:secure_url" 
58 # content="https://www.python.org/static/opengraph-icon-200x200.png">\n    \n    
59 # <meta property="og:url" content="https://www.python.org/">\n\n    
60 # <link rel="author" href="/static/humans.txt">\n\n    
61 # <link rel="alternate" type="application/rss+xml" title="Python Enhancement Proposals"\n  
62 # href="https://www.python.org/dev/peps/peps.rss/">\n  
63 #  <link rel="alternate" type="application/rss+xml" title="Python Job Opportunities"\n          
64 # href="https://www.python.org/jobs/feed/rss/">\n    
65 # <link rel="alternate" type="application/rss+xml" title="Python Software Foundation News"\n  
66 #         href="https://feeds.feedburner.com/PythonSoftwareFoundationNews">\n    
67 # <link rel="alternate" type="application/rss+xml" title="Python Insider"\n          
68 # href="https://feeds.feedburner.com/PythonInsider">\n\n    \n\n    \n    
69 # <script type="application/ld+json">\n     {\n       "@context": "http://schema.org",\n       
70 # "@type": "WebSite",\n       "url": "https://www.python.org/",\n       
71 # "potentialAction": {\n         "@type": "SearchAction",\n         "target": "https://www.python.org/search/?q={search_term_string}",\n         "query-input": "required name=search_term_string"\n       }\n     }\n    </script>\n\n    \n    <script type="text/javascript">\n    var _gaq = _gaq || [];\n    _gaq.push([\'_setAccount\', \'UA-39055973-1\']);\n    _gaq.push([\'_trackPageview\']);\n\n    (function() {\n        var ga = document.createElement(\'script\'); ga.type = \'text/javascript\'; ga.async = true;\n        ga.src = (\'https:\' == document.location.protocol ? \'https://ssl\' : \'http://www\') + \'.google-analytics.com/ga.js\';\n        var s = document.getElementsByTagName(\'script\')[0]; s.parentNode.insertBefore(ga, s);\n    })();\n    </script>\n    \n</head>\n\n<body class="python home" id="homepage">\n\n    <div id="touchnav-wrapper">\n\n        <div id="nojs" class="do-not-print">\n            <p><strong>Notice:</strong> While Javascript is not essential for this website, your interaction with the content will be limited. 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data-shell-container="#dive-into-python" href="/shell/">&gt;_\n                        <span class="message">Launch Interactive Shell</span>\n                    </a>\n                </li>\n            </ul>\n\n            <ul class="slides menu">\n                \n                <li>\n                    <div class="slide-code"><pre><code><span class="comment"># Python 3: Fibonacci series up to n</span>\r\n>>> def fib(n):\r\n>>>     a, b = 0, 1\r\n>>>     while a &lt; n:\r\n>>>         print(a, end=\' \')\r\n>>>         a, b = b, a+b\r\n>>>     print()\r\n>>> fib(1000)\r\n<span class="output">0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987</span></code></pre></div>\n                    <div class="slide-copy"><h1>Functions Defined</h1>\r\n<p>The core of extensible programming is defining functions. Python allows mandatory and optional arguments, keyword arguments, and even arbitrary argument lists. <a href="//docs.python.org/3/tutorial/controlflow.html#defining-functions">More about defining functions in Python&nbsp;3</a></p></div>\n                </li>\n                \n                <li>\n                    <div class="slide-code"><pre><code><span class="comment"># Python 3: List comprehensions</span>\r\n>>> fruits = [\'Banana\', \'Apple\', \'Lime\']\r\n>>> loud_fruits = [fruit.upper() for fruit in fruits]\r\n>>> print(loud_fruits)\r\n<span class="output">[\'BANANA\', \'APPLE\', \'LIME\']</span>\r\n\r\n<span class="comment"># List and the enumerate function</span>\r\n>>> list(enumerate(fruits))\r\n<span class="output">[(0, \'Banana\'), (1, \'Apple\'), (2, \'Lime\')]</span></code></pre></div>\n                    <div class="slide-copy"><h1>Compound Data Types</h1>\r\n<p>Lists (known as arrays in other languages) are one of the compound data types that Python understands. Lists can be indexed, sliced and manipulated with other built-in functions. <a href="//docs.python.org/3/tutorial/introduction.html#lists">More about lists in Python&nbsp;3</a></p></div>\n                </li>\n                \n                <li>\n                    <div class="slide-code"><pre><code><span class="comment"># Python 3: Simple arithmetic</span>\r\n>>> 1 / 2\r\n<span class="output">0.5</span>\r\n>>> 2 ** 3\r\n<span class="output">8</span>\r\n>>> 17 / 3  <span class="comment"># classic division returns a float</span>\r\n<span class="output">5.666666666666667</span>\r\n>>> 17 // 3  <span class="comment"># floor division</span>\r\n<span class="output">5</span></code></pre></div>\n                    <div class="slide-copy"><h1>Intuitive Interpretation</h1>\r\n<p>Calculations are simple with Python, and expression syntax is straightforward: the operators <code>+</code>, <code>-</code>, <code>*</code> and <code>/</code> work as expected; parentheses <code>()</code> can be used for grouping. <a href="http://docs.python.org/3/tutorial/introduction.html#using-python-as-a-calculator">More about simple math functions in Python&nbsp;3</a>.</p></div>\n                </li>\n                \n                <li>\n                    <div class="slide-code"><pre><code><span class="comment"># Python 3: Simple output (with Unicode)</span>\r\n>>> print("Hello, I\'m Python!")\r\n<span class="output">Hello, I\'m Python!</span>\r\n\r\n<span class="comment"># Input, assignment</span>\r\n>>> name = input(\'What is your name?\\n\')\r\n>>> print(\'Hi, %s.\' % name)\r\n<span class="output">What is your name?\r\nPython\r\nHi, Python.</span></code></pre></div>\n                    <div class="slide-copy"><h1>Quick &amp; Easy to Learn</h1>\r\n<p>Experienced programmers in any other language can pick up Python very quickly, and beginners find the clean syntax and indentation structure easy to learn. <a href="//docs.python.org/3/tutorial/">Whet your appetite</a> with our Python&nbsp;3 overview.</p>\r\n                   </div>\n                </li>\n                \n                <li>\n                    <div class="slide-code"><pre><code><span class="comment"># For loop on a list</span>\r\n>>> numbers = [2, 4, 6, 8]\r\n>>> product = 1\r\n>>> for number in numbers:\r\n...    product = product * number\r\n... \r\n>>> print(\'The product is:\', product)\r\n<span class="output">The product is: 384</span></code></pre></div>\n                    <div class="slide-copy"><h1>All the Flow You&rsquo;d Expect</h1>\r\n<p>Python knows the usual control flow statements that other languages speak &mdash; <code>if</code>, <code>for</code>, <code>while</code> and <code>range</code> &mdash; with some of its own twists, of course. <a href="//docs.python.org/3/tutorial/controlflow.html">More control flow tools in Python&nbsp;3</a></p></div>\n                </li>\n                \n            </ul>\n        </div>\n\n\n                </div>\n\n                \n        <div class="introduction">\n            <p>Python is a programming language that lets you work quickly <span class="breaker"></span>and integrate systems more effectively. <a class="readmore" href="/doc/">Learn More</a></p>\n        </div>\n\n\n             </div><!-- end .container -->\n        </header>\n\n        <div id="content" class="content-wrapper">\n            <!-- Main Content Column -->\n            <div class="container">\n\n                <section class="main-content " role="main">\n\n                    \n                    \n\n                    \n\n                    \n\n                <div class="row">\n\n                    <div class="small-widget get-started-widget">\n                        <h2 class="widget-title"><span aria-hidden="true" class="icon-get-started"></span>Get Started</h2>\r\n<p>Whether you\'re new to programming or an experienced developer, it\'s easy to learn and use Python.</p>\r\n<p><a href="/about/gettingstarted/">Start with our Beginner&rsquo;s Guide</a></p>\n                    </div>\n\n                    <div class="small-widget download-widget">\n                        <h2 class="widget-title"><span aria-hidden="true" class="icon-download"></span>Download</h2>\n<p>Python source code and installers are available for download for all versions!</p>\n<p>Latest: <a href="/downloads/release/python-372/">Python 3.7.2</a></p>\n                    </div>\n\n                    <div class="small-widget documentation-widget">\n                        <h2 class="widget-title"><span aria-hidden="true" class="icon-documentation"></span>Docs</h2>\r\n<p>Documentation for Python\'s standard library, along with tutorials and guides, are available online.</p>\r\n<p><a href="https://docs.python.org">docs.python.org</a></p>\n                    </div>\n\n                    <div class="small-widget jobs-widget last">\n                        <h2 class="widget-title"><span aria-hidden="true" class="icon-jobs"></span>Jobs</h2>\r\n<p>Looking for work or have a Python related position that you\'re trying to hire for? 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href="http://feedproxy.google.com/~r/PythonInsider/~3/KoVsY316T7U/python-372-and-368-are-now-available.html">Python&nbsp;3.7.2&nbsp;and&nbsp;3.6.8&nbsp;are now available. &nbsp;Python 3.7.2 is the next maintenance release ...</a></li>\n                                \n                                <li>\n<time datetime="2018-12-24T11:26:00+00:00"><span class="say-no-more">2018-</span>12-24</time>\n <a href="http://feedproxy.google.com/~r/PythonInsider/~3/o5ROzg9M8NY/python-372-and-368-are-now-available.html">Python&nbsp;3.7.2&nbsp;and&nbsp;3.6.8&nbsp;are now available. &nbsp;Python 3.7.2 is the next maintenance release ...</a></li>\n                                \n                                <li>\n<time datetime="2018-12-20T17:55:00.000003+00:00"><span class="say-no-more">2018-</span>12-20</time>\n <a href="http://feedproxy.google.com/~r/PythonSoftwareFoundationNews/~3/UJLhXUl_Le8/upcoming-pypi-improvements-for-2019.html">The Python Package Index (PyPI) is far and away the 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View Code
 1 from urllib.request import urlopen
 2 fp = urlopen("http://www.python.org")
 3 op = open("python.html","wb")
 4 n = 0
 5 while True:
 6     s = fp.read(1024)
 7     if not s:
 8         break
 9     op.write(s)
10     n = n + len(s)
11 fp.close()
12 op.close()
13 print ("retrieved", n, "bytes from", fp.url)
View Code
1) 使用代理
2) 直接保存URL资源
1 from urllib.request import urlretrieve
2 filename, m = urlretrieve("http://www.baidu.com")
3 filename
4 filename, m = urlretrieve("http://www.baidu.com", filename="I:/book/source/html/baidu.html")
5 filename
View Code
 1 from urllib.request import urlretrieve
 2 def reporthook(block_count, block_size, file_size):
 3     if file_size == -1:
 4         print ("retrieved data", "block_count * bolck_size")
 5     else:
 6         print ("retrieved data", "block_count * bolck_size", "/", "file_size")
 7 urlretrieve("file:///I:/book/source/html/python.html", filename="", reporthook=reporthook)
 8     retrieve data 0 / 16578
 9     retrieve data 8192 / 16578
10     retrieve data 16384 / 16578
11     retrieve data 24576 / 16578
12 urlretrieve("http://www.python.org", filename="", reporthook=reporthook)
13 retrieve data 0 / 16578
14 retrieve data 8192 / 16578
15 retrieve data 16384 / 16578
16 retrieve data 24576 / 16578
17 urlretrieve("http://www.google.com", filename="", reporthook=reporthook)
18 retrieve datad 0
19 retrieve datad 8192
View Code
 1 def download(url, filename=""):
 2     def reporthook(block_count, block_size, file_size):
 3         if file_size == -1:
 4             print("Can't determine the file size, now retrieved", block_count*block_size)
 5         else:
 6             percentage = int((block_count*block_size*100.0)/file_size)
 7             if percentage > 100:
 8                 print("100%")
 9             else:
10                 print("%d%%" % (percentage))
11     filehandler, m = urlretrieve(url, filename, reporthook=reporthook)
12     print("Done")
13 return filehandler
View Code

 13.4.2 分析返回资源的相关信息

1 from urllib.request import urlopen
2 r = urlopen("http://baidu.com")
3 print(r.geturl())
4 print(r.url)
5 # 输出：http://baidu.com
6 # http://baidu.com
View Code
1 from urllib.request import urlopen
2 r = urlopen("http://baidu.com")
3 m = r.info()
4 m.get_countent_type()
5 m.get_countent_maintype()
6 m.get_countent_subtype()
7 print(m)
View Code
 1 from urllib.request import urlopen
 2 r = urlopen("http://baidu.com")
 3 m = r.info()
 4 m.get_countent_type()
 5 m.get_countent_maintype()
 6 m.get_countent_subtype()
 7 m
 8 for k,v in r.info().items():
 9     print (k, "=", v)
10 r.headers
View Code

13.4.3 自定义获取资源方式

1）访问需要简单认证的URL资源
 1 def prompt_user_passwd(self, host, realm):
 2     """Override this in a GUI environment!"""
 3     import getpass
 4     try:
 5         user = input("Enter username for %s at %s:" % (realm, host))
 6         passwd = getpass.getpass("Enter password for %s in %s at %s:" % (user, realm, host))
 7         return user, passwd
 8     except KeyboardInterrupt:
 9         print()
10         return None, None
View Code

 

posted @ 2019-01-04 22:22  无声胜有声  阅读(778)  评论(0)    收藏  举报