我正在Google App Engine上构建应用程序。我是Python的新手，在过去3天里，我一直对下面的问题problem之以鼻。

我有一个表示RSS Feed的类，在这个类中，我有一个名为setUrl的方法。输入此方法的是URL。

我正在尝试使用re python模块来验证RFC 3986 Reg-ex（http://www.ietf.org/rfc/rfc3986.txt）

下面是一个片段，哪个应该工作？

p = re.compile('^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))?')
m = p.match(url)
if m:
  self.url = url
  return url

urlparse（py2，py3）模块是解析（和验证）URL的一种简单方法。

正则表达式是太多的工作。

没有“验证”方法，因为几乎所有内容都是有效的URL。有一些标点符号规则可以将其拆分。没有标点符号，您仍然有一个有效的URL。

仔细检查RFC，看看是否可以构造“无效” URL。规则非常灵活。

例如:::::，一个有效的URL。路径是":::::"。漂亮的文件名，但是有效的文件名。

此外，/////也是有效的网址。netloc（“主机名”）为""。路径是"///"。再次，愚蠢。也有效。此URL规范化为"///"等效的URL 。

类似的东西"bad://///worse/////"是完全有效的。哑巴但有效。

底线。对其进行解析，然后查看片段，看看它们是否在某种程度上令人不快。

您是否希望方案始终为“ http”？您是否希望netloc始终为“ www.somename.somedomain”？您是否要让路径看起来像Unix？还是像窗户？是否要删除查询字符串？还是保留它？

这些不是RFC指定的验证。这些是您的应用程序独有的验证。

这是解析URL的完整正则表达式。

(?:http://(?:(?:(?:(?:(?:[a-zA-Z\d](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?)\.
)*(?:[a-zA-Z](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?))|(?:(?:\d+)(?:\.(?:\d+)
){3}))(?::(?:\d+))?)(?:/(?:(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F
\d]{2}))|[;:@&=])*)(?:/(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{
2}))|[;:@&=])*))*)(?:\?(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{
2}))|[;:@&=])*))?)?)|(?:ftp://(?:(?:(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?
:%[a-fA-F\d]{2}))|[;?&=])*)(?::(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-
fA-F\d]{2}))|[;?&=])*))?@)?(?:(?:(?:(?:(?:[a-zA-Z\d](?:(?:[a-zA-Z\d]|-
)*[a-zA-Z\d])?)\.)*(?:[a-zA-Z](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?))|(?:(?
:\d+)(?:\.(?:\d+)){3}))(?::(?:\d+))?))(?:/(?:(?:(?:(?:[a-zA-Z\d$\-_.+!
*'(),]|(?:%[a-fA-F\d]{2}))|[?:@&=])*)(?:/(?:(?:(?:[a-zA-Z\d$\-_.+!*'()
,]|(?:%[a-fA-F\d]{2}))|[?:@&=])*))*)(?:;type=[AIDaid])?)?)|(?:news:(?:
(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[;/?:&=])+@(?:(?:(
?:(?:[a-zA-Z\d](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?)\.)*(?:[a-zA-Z](?:(?:[
a-zA-Z\d]|-)*[a-zA-Z\d])?))|(?:(?:\d+)(?:\.(?:\d+)){3})))|(?:[a-zA-Z](
?:[a-zA-Z\d]|[_.+-])*)|\*))|(?:nntp://(?:(?:(?:(?:(?:[a-zA-Z\d](?:(?:[
a-zA-Z\d]|-)*[a-zA-Z\d])?)\.)*(?:[a-zA-Z](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d
])?))|(?:(?:\d+)(?:\.(?:\d+)){3}))(?::(?:\d+))?)/(?:[a-zA-Z](?:[a-zA-Z
\d]|[_.+-])*)(?:/(?:\d+))?)|(?:telnet://(?:(?:(?:(?:(?:[a-zA-Z\d$\-_.+
!*'(),]|(?:%[a-fA-F\d]{2}))|[;?&=])*)(?::(?:(?:(?:[a-zA-Z\d$\-_.+!*'()
,]|(?:%[a-fA-F\d]{2}))|[;?&=])*))?@)?(?:(?:(?:(?:(?:[a-zA-Z\d](?:(?:[a
-zA-Z\d]|-)*[a-zA-Z\d])?)\.)*(?:[a-zA-Z](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d]
)?))|(?:(?:\d+)(?:\.(?:\d+)){3}))(?::(?:\d+))?))/?)|(?:gopher://(?:(?:
(?:(?:(?:[a-zA-Z\d](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?)\.)*(?:[a-zA-Z](?:
(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?))|(?:(?:\d+)(?:\.(?:\d+)){3}))(?::(?:\d+
))?)(?:/(?:[a-zA-Z\d$\-_.+!*'(),;/?:@&=]|(?:%[a-fA-F\d]{2}))(?:(?:(?:[
a-zA-Z\d$\-_.+!*'(),;/?:@&=]|(?:%[a-fA-F\d]{2}))*)(?:%09(?:(?:(?:[a-zA
-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[;:@&=])*)(?:%09(?:(?:[a-zA-Z\d$
\-_.+!*'(),;/?:@&=]|(?:%[a-fA-F\d]{2}))*))?)?)?)?)|(?:wais://(?:(?:(?:
(?:(?:[a-zA-Z\d](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?)\.)*(?:[a-zA-Z](?:(?:
[a-zA-Z\d]|-)*[a-zA-Z\d])?))|(?:(?:\d+)(?:\.(?:\d+)){3}))(?::(?:\d+))?
)/(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))*)(?:(?:/(?:(?:[a-zA
-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))*)/(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(
?:%[a-fA-F\d]{2}))*))|\?(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]
{2}))|[;:@&=])*))?)|(?:mailto:(?:(?:[a-zA-Z\d$\-_.+!*'(),;/?:@&=]|(?:%
[a-fA-F\d]{2}))+))|(?:file://(?:(?:(?:(?:(?:[a-zA-Z\d](?:(?:[a-zA-Z\d]
|-)*[a-zA-Z\d])?)\.)*(?:[a-zA-Z](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?))|(?:
(?:\d+)(?:\.(?:\d+)){3}))|localhost)?/(?:(?:(?:(?:[a-zA-Z\d$\-_.+!*'()
,]|(?:%[a-fA-F\d]{2}))|[?:@&=])*)(?:/(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(
?:%[a-fA-F\d]{2}))|[?:@&=])*))*))|(?:prospero://(?:(?:(?:(?:(?:[a-zA-Z
\d](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?)\.)*(?:[a-zA-Z](?:(?:[a-zA-Z\d]|-)
*[a-zA-Z\d])?))|(?:(?:\d+)(?:\.(?:\d+)){3}))(?::(?:\d+))?)/(?:(?:(?:(?
:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[?:@&=])*)(?:/(?:(?:(?:[a-
zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[?:@&=])*))*)(?:(?:;(?:(?:(?:[
a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[?:@&])*)=(?:(?:(?:[a-zA-Z\d
$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[?:@&])*)))*)|(?:ldap://(?:(?:(?:(?:
(?:(?:[a-zA-Z\d](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?)\.)*(?:[a-zA-Z](?:(?:
[a-zA-Z\d]|-)*[a-zA-Z\d])?))|(?:(?:\d+)(?:\.(?:\d+)){3}))(?::(?:\d+))?
))?/(?:(?:(?:(?:(?:(?:(?:[a-zA-Z\d]|%(?:3\d|[46][a-fA-F\d]|[57][Aa\d])
)|(?:%20))+|(?:OID|oid)\.(?:(?:\d+)(?:\.(?:\d+))*))(?:(?:%0[Aa])?(?:%2
0)*)=(?:(?:%0[Aa])?(?:%20)*))?(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F
\d]{2}))*))(?:(?:(?:%0[Aa])?(?:%20)*)\+(?:(?:%0[Aa])?(?:%20)*)(?:(?:(?
:(?:(?:[a-zA-Z\d]|%(?:3\d|[46][a-fA-F\d]|[57][Aa\d]))|(?:%20))+|(?:OID
|oid)\.(?:(?:\d+)(?:\.(?:\d+))*))(?:(?:%0[Aa])?(?:%20)*)=(?:(?:%0[Aa])
?(?:%20)*))?(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))*)))*)(?:(
?:(?:(?:%0[Aa])?(?:%20)*)(?:[;,])(?:(?:%0[Aa])?(?:%20)*))(?:(?:(?:(?:(
?:(?:[a-zA-Z\d]|%(?:3\d|[46][a-fA-F\d]|[57][Aa\d]))|(?:%20))+|(?:OID|o
id)\.(?:(?:\d+)(?:\.(?:\d+))*))(?:(?:%0[Aa])?(?:%20)*)=(?:(?:%0[Aa])?(
?:%20)*))?(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))*))(?:(?:(?:
%0[Aa])?(?:%20)*)\+(?:(?:%0[Aa])?(?:%20)*)(?:(?:(?:(?:(?:[a-zA-Z\d]|%(
?:3\d|[46][a-fA-F\d]|[57][Aa\d]))|(?:%20))+|(?:OID|oid)\.(?:(?:\d+)(?:
\.(?:\d+))*))(?:(?:%0[Aa])?(?:%20)*)=(?:(?:%0[Aa])?(?:%20)*))?(?:(?:[a
-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))*)))*))*(?:(?:(?:%0[Aa])?(?:%2
0)*)(?:[;,])(?:(?:%0[Aa])?(?:%20)*))?)(?:\?(?:(?:(?:(?:[a-zA-Z\d$\-_.+
!*'(),]|(?:%[a-fA-F\d]{2}))+)(?:,(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-f
A-F\d]{2}))+))*)?)(?:\?(?:base|one|sub)(?:\?(?:((?:[a-zA-Z\d$\-_.+!*'(
),;/?:@&=]|(?:%[a-fA-F\d]{2}))+)))?)?)?)|(?:(?:z39\.50[rs])://(?:(?:(?
:(?:(?:[a-zA-Z\d](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?)\.)*(?:[a-zA-Z](?:(?
:[a-zA-Z\d]|-)*[a-zA-Z\d])?))|(?:(?:\d+)(?:\.(?:\d+)){3}))(?::(?:\d+))
?)(?:/(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))+)(?:\+(?:(?:
[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))+))*(?:\?(?:(?:[a-zA-Z\d$\-_
.+!*'(),]|(?:%[a-fA-F\d]{2}))+))?)?(?:;esn=(?:(?:[a-zA-Z\d$\-_.+!*'(),
]|(?:%[a-fA-F\d]{2}))+))?(?:;rs=(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA
-F\d]{2}))+)(?:\+(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))+))*)
?))|(?:cid:(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[;?:@&=
])*))|(?:mid:(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[;?:@
&=])*)(?:/(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[;?:@&=]
)*))?)|(?:vemmi://(?:(?:(?:(?:(?:[a-zA-Z\d](?:(?:[a-zA-Z\d]|-)*[a-zA-Z
\d])?)\.)*(?:[a-zA-Z](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?))|(?:(?:\d+)(?:\
.(?:\d+)){3}))(?::(?:\d+))?)(?:/(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a
-fA-F\d]{2}))|[/?:@&=])*)(?:(?:;(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a
-fA-F\d]{2}))|[/?:@&])*)=(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d
]{2}))|[/?:@&])*))*))?)|(?:imap://(?:(?:(?:(?:(?:(?:(?:[a-zA-Z\d$\-_.+
!*'(),]|(?:%[a-fA-F\d]{2}))|[&=~])+)(?:(?:;[Aa][Uu][Tt][Hh]=(?:\*|(?:(
?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[&=~])+))))?)|(?:(?:;[
Aa][Uu][Tt][Hh]=(?:\*|(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2
}))|[&=~])+)))(?:(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[
&=~])+))?))@)?(?:(?:(?:(?:(?:[a-zA-Z\d](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])
?)\.)*(?:[a-zA-Z](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?))|(?:(?:\d+)(?:\.(?:
\d+)){3}))(?::(?:\d+))?))/(?:(?:(?:(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:
%[a-fA-F\d]{2}))|[&=~:@/])+)?;[Tt][Yy][Pp][Ee]=(?:[Ll](?:[Ii][Ss][Tt]|
[Ss][Uu][Bb])))|(?:(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))
|[&=~:@/])+)(?:\?(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[
&=~:@/])+))?(?:(?:;[Uu][Ii][Dd][Vv][Aa][Ll][Ii][Dd][Ii][Tt][Yy]=(?:[1-
9]\d*)))?)|(?:(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[&=~
:@/])+)(?:(?:;[Uu][Ii][Dd][Vv][Aa][Ll][Ii][Dd][Ii][Tt][Yy]=(?:[1-9]\d*
)))?(?:/;[Uu][Ii][Dd]=(?:[1-9]\d*))(?:(?:/;[Ss][Ee][Cc][Tt][Ii][Oo][Nn
]=(?:(?:(?:[a-zA-Z\d$\-_.+!*'(),]|(?:%[a-fA-F\d]{2}))|[&=~:@/])+)))?))
)?)|(?:nfs:(?:(?://(?:(?:(?:(?:(?:[a-zA-Z\d](?:(?:[a-zA-Z\d]|-)*[a-zA-
Z\d])?)\.)*(?:[a-zA-Z](?:(?:[a-zA-Z\d]|-)*[a-zA-Z\d])?))|(?:(?:\d+)(?:
\.(?:\d+)){3}))(?::(?:\d+))?)(?:(?:/(?:(?:(?:(?:(?:[a-zA-Z\d\$\-_.!~*'
(),])|(?:%[a-fA-F\d]{2})|[:@&=+])*)(?:/(?:(?:(?:[a-zA-Z\d\$\-_.!~*'(),
])|(?:%[a-fA-F\d]{2})|[:@&=+])*))*)?)))?)|(?:/(?:(?:(?:(?:(?:[a-zA-Z\d
\$\-_.!~*'(),])|(?:%[a-fA-F\d]{2})|[:@&=+])*)(?:/(?:(?:(?:[a-zA-Z\d\$\
-_.!~*'(),])|(?:%[a-fA-F\d]{2})|[:@&=+])*))*)?))|(?:(?:(?:(?:(?:[a-zA-
Z\d\$\-_.!~*'(),])|(?:%[a-fA-F\d]{2})|[:@&=+])*)(?:/(?:(?:(?:[a-zA-Z\d
\$\-_.!~*'(),])|(?:%[a-fA-F\d]{2})|[:@&=+])*))*)?)))

考虑到它的复杂性，我认为您应该使用urlparse方法。

为了完整起见，以下是上述正则表达式的伪BNF（作为文档）：

; URL的通用形式为：

genericurl =方案“：” schemepart

; 这里定义了特定的预定义方案。新计划
; 可能已在IANA上注册

url = httpurl | ftpurl | 新闻网址|
                 nntpurl | telneturl | gopherurl |
                 waisurl | mailtourl | fileurl |
                 繁荣| 其他网址

; 新方案遵循通用语法
otherurl =通用网址

; 该计划是小写的；口译员应忽略大小写
方案= 1 * [lowalpha | 数字| “ +” | “-” | “。” ]
schemepart = * xchar | ip方案


; 基于ip协议的URL scheme部分：

ip-schemepart =“ //”登录[“ /” urlpath]

登录名= [用户[“：”密码]“ @”]主机端口
hostport =主机[“：”端口]
主机=主机名| 主机号码
主机名= * [domainlabel“。” ] toplabel
domainlabel =字母数字| 字母数字* [字母数字| “-”]字母数字
toplabel = alpha | 字母* [字母数字| “-”]字母数字
字母数字=字母| 数字
主机号=数字“。” 数字“。” 数字“。” 数字
端口=数字
用户= * [uchar | “;” | “？” | “＆” | “ =”]
密码= * [uchar | “;” | “？” | “＆” | “ =”]
urlpath = * xchar; 取决于协议，请参阅第3.1节

; 预定义的方案：

; FTP（另请参阅RFC959）

ftpurl =“ ftp：//”登录[“ /” fpath [“; type =” ftptype]]
fpath = fsegment * [“ /” fsegment]
fsegment = * [uchar | “？” | “：” | “ @” | “＆” | “ =”]
ftptype =“ A” | “我” | “ D” | “ a” | “我” | “ d”

; 文件

fileurl =“ file：//” [主机| “本地主机”]“ /” fpath

; HTTP

httpurl =“ http：//”主机端口[“ /” hpath [“？” 搜索]]
hpath = hsegment * [“ /” hsegment]
hsegment = * [uchar | “;” | “：” | “ @” | “＆” | “ =”]
搜索= * [uchar | “;” | “：” | “ @” | “＆” | “ =”]

; GOPHER（另请参阅RFC1436）

gopherurl =“ gopher：//”主机端口[/ [gtype [选择器
                 [“％09”搜索[“％09” gopher + _string]]]]]
gtype = xchar
选择器= * xchar
gopher + _string = * xchar

; MAILTO（另请参阅RFC822）

mailtourl =“ mailto：”已编码822addr
encode822addr = 1 * xchar; 在RFC822中进一步定义

; 新闻（另请参阅RFC1036）

newsurl =“新闻：” grouppart
grouppart =“ *” | 组| 文章
组= alpha * [alpha | 数字| “-” | “。” | “ +” | “ _”]
文章= 1 * [uchar | “;” | “ /” | “？” | “：” | “＆” | “ =”]“ @”主机

; NNTP（另请参阅RFC977）

nntpurl =“ nntp：//”主机端口“ /”组[“ /”数字]

; 电信网

telneturl =“ telnet：//”登录[“ /”]

; WAIS（另请参阅RFC1625）

waisurl = wais数据库| waisindex | 怀斯多克
waisdatabase =“ wais：//”主机端口“ /”数据库
waisindex =“ wais：//”主机端口“ /”数据库“？” 搜索
waisdoc =“ wais：//”主机端口“ /”数据库“ /” wtype“ /” wpath
数据库= * uchar
wtype = * uchar
wpath = * uchar

; PROSPERO

prosperourl =“ prospero：//”主机端口“ /” ppath * [fieldspec]
ppath = psegment * [“ /” psegment]
psegment = * [uchar | “？” | “：” | “ @” | “＆” | “ =”]
fieldspec =“;” fieldname“ =” fieldvalue
fieldname = * [uchar | “？” | “：” | “ @” | “＆”]
fieldvalue = * [uchar | “？” | “：” | “ @” | “＆”]

; 其他定义

lowalpha =“ a” | “ b” | “ c” | “ d” | “ e” | “ f” | “ g” | “ h” |
                 “我” | “ j” | “ k” | “ l” | “ m” | “ n” | “ o” | “ p” |
                 “ q” | “ r” | “ s” | “ t” | “ u” | “ v” | “ w” | “ x” |
                 “ y” | “ z”
hialpha =“ A” | “ B” | “ C” | “ D” | “ E” | “ F” | “ G” | “ H” | “我” |
                 “ J” | “ K” | “ L” | “ M” | “ N” | “ O” | “ P” | “ Q” | “ R” |
                 “ S” | “ T” | “ U” | “ V” | “ W” | “ X” | “ Y” | “ Z”
alpha = lowalpha | Hialpha
digit =“ 0” | “ 1” | “ 2” | “ 3” | “ 4” | “ 5” | “ 6” | “ 7” |
                 “ 8” | “ 9”
安全=“ $” | “-” | “ _” | “。” | “ +”
extra =“！” | “ *” | “'” | “（” |“）” | “，”
national =“ {” | “}” | “ |” | “ \” | “ ^” | “〜” | “ [” | “]” | “`”
标点符号=“” | “＃” | “％” |


保留=“;” | “ /” | “？” | “：” | “ @” | “＆” | “ =”
十六进制=数字| “ A” | “ B” | “ C” | “ D” | “ E” | “ F” |
                 “ a” | “ b” | “ c” | “ d” | “ e” | “F”
转义=“％”十六进制十六进制

未保留= alpha | 数字| 安全| 额外
uchar =保留| 逃逸
xchar =保留| 保留| 逃逸
位数= 1 *位数

我使用的是Django所使用的，看来效果很好：

def is_valid_url(url):
    import re
    regex = re.compile(
        r'^https?://'  # http:// or https://
        r'(?:(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+[A-Z]{2,6}\.?|'  # domain...
        r'localhost|'  # localhost...
        r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})' # ...or ip
        r'(?::\d+)?'  # optional port
        r'(?:/?|[/?]\S+)$', re.IGNORECASE)
    return url is not None and regex.search(url)

您随时可以在这里查看最新版本：https：//github.com/django/django/blob/master/django/core/validators.py#L74

我承认，我发现你的正则表达完全无法理解。我想知道您是否可以使用urlparse代替？就像是：

pieces = urlparse.urlparse(url)
assert all([pieces.scheme, pieces.netloc])
assert set(pieces.netloc) <= set(string.letters + string.digits + '-.')  # and others?
assert pieces.scheme in ['http', 'https', 'ftp']  # etc.

它可能会比较慢，并且可能会错过条件，但是（对我而言）它似乎比URL的正则表达式更易于阅读和调试。

urlparse很高兴使用无效的URL，它比任何一种验证器都更像是一个字符串字符串拆分库。例如：

from urlparse import urlparse
urlparse('http://----')
# returns: ParseResult(scheme='http', netloc='----', path='', params='', query='', fragment='')

根据情况，这可能很好。

如果您最信任数据，并且只想验证协议为HTTP，则 urlparse就是完美的选择。

如果要使该URL实际上是合法URL，请使用可笑的正则表达式

如果您想确保它是一个真实的网址，

import urllib
try:
    urllib.urlopen(url)
except IOError:
    print "Not a real URL"

http://pypi.python.org/pypi/rfc3987提供了正则表达式，以与RFC 3986和RFC 3987中的规则保持一致（即不与特定于方案的规则保持一致）。

IRI_reference的正则表达式为：

(?P<scheme>[a-zA-Z][a-zA-Z0-9+.-]*):(?://(?P<iauthority>(?:(?P<iuserinfo>(?:(?:[
a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U0002
0000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U
00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009ff
fd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U00
0dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:)*)@)?(?P<ihost>\
\[(?:(?:[0-9A-F]{1,4}:){6}(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4]
[0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|::(?:[0
-9A-F]{1,4}:){5}(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]
?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|[0-9A-F]{1,4}?::(
?:[0-9A-F]{1,4}:){4}(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|
[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|(?:(?:[0-9A-F
]{1,4}:)?[0-9A-F]{1,4})?::(?:[0-9A-F]{1,4}:){3}(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?
:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[
0-9][0-9]?)))|(?:(?:[0-9A-F]{1,4}:){,2}[0-9A-F]{1,4})?::(?:[0-9A-F]{1,4}:){2}(?:
[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3
}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|(?:(?:[0-9A-F]{1,4}:){,3}[0-9A-F]{1,
4})?::(?:[0-9A-F]{1,4}:)(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0
-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|(?:(?:[0-
9A-F]{1,4}:){,4}[0-9A-F]{1,4})?::(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]
|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|
(?:(?:[0-9A-F]{1,4}:){,5}[0-9A-F]{1,4})?::[0-9A-F]{1,4}|(?:(?:[0-9A-F]{1,4}:){,6
}[0-9A-F]{1,4})?::|v[0-9A-F]+\\.(?:[a-zA-Z0-9_.~-]|[!$&'()*+,;=]|:)+)\\]|(?:(?:(
?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][
0-9]?))|(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\
U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U000500
00-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00
090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd
\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=])*)(
?::(?P<port>[0-9]*))?)(?P<ipath>(?:/(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\uf
dcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\
U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007f
ffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U0
00bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-
F][0-9A-F]|[!$&'()*+,;=]|:|@)*)*)|(?P<ipath>/(?:(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7
ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000
-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U0007
0000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U
000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000eff
fd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)+(?:/(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff
\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\
U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U000700
00-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U00
0b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd
])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)*)*)?)|(?P<ipath>(?:(?:[a-zA-Z0-9._~-]|[\
xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U
00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006ff
fd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U00
0afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-
\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)+(?:/(?:(?:[a-zA-Z0-9._~-]|[\xa
0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00
030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd
\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000a
fffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U
000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)*)*)|(?P<ipath>))(?:\\?(?P<iquery
>(?:(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U000
1fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\
U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U000900
00-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U00
0d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)|[\
ue000-\uf8ff\U000f0000-\U000ffffd\U00100000-\U0010fffd]|/|\\?)*))?(?:\\#(?P<ifra
gment>(?:(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-
\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050
000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U0
0090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfff
d\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|
@)|/|\\?)*))?|(?:(?://(?P<iauthority>(?:(?P<iuserinfo>(?:(?:[a-zA-Z0-9._~-]|[\xa
0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00
030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd
\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000a
fffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U
000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:)*)@)?(?P<ihost>\\[(?:(?:[0-9A-F]{1,
4}:){6}(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-
9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|::(?:[0-9A-F]{1,4}:){5}(?:
[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3
}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|[0-9A-F]{1,4}?::(?:[0-9A-F]{1,4}:){4
}(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\
.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|(?:(?:[0-9A-F]{1,4}:)?[0-9A-F]{1
,4})?::(?:[0-9A-F]{1,4}:){3}(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-
4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|(?:(?
:[0-9A-F]{1,4}:){,2}[0-9A-F]{1,4})?::(?:[0-9A-F]{1,4}:){2}(?:[0-9A-F]{1,4}:[0-9A
-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][
0-9]|[01]?[0-9][0-9]?)))|(?:(?:[0-9A-F]{1,4}:){,3}[0-9A-F]{1,4})?::(?:[0-9A-F]{1
,4}:)(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]
?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|(?:(?:[0-9A-F]{1,4}:){,4}[0-
9A-F]{1,4})?::(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[
0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|(?:(?:[0-9A-F]{1,4}
:){,5}[0-9A-F]{1,4})?::[0-9A-F]{1,4}|(?:(?:[0-9A-F]{1,4}:){,6}[0-9A-F]{1,4})?::|
v[0-9A-F]+\\.(?:[a-zA-Z0-9_.~-]|[!$&'()*+,;=]|:)+)\\]|(?:(?:(?:25[0-5]|2[0-4][0-
9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))|(?:(?:[a-zA
-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000
-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U0006
0000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U
000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dff
fd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=])*)(?::(?P<port>[0-9]*)
)?)(?P<ipath>(?:/(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U0
0010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fff
d\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U000
8fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\
U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*
+,;=]|:|@)*)*)|(?P<ipath>/(?:(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufd
f0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U000400
00-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00
080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd
\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A
-F]|[!$&'()*+,;=]|:|@)+(?:/(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0
-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000
-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U0008
0000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U
000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F
]|[!$&'()*+,;=]|:|@)*)*)?)|(?P<ipath>(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\u
fdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd
\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007
fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U
000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A
-F][0-9A-F]|[!$&'()*+,;=]|@)+(?:/(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf
\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00
040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd
\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000b
fffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][
0-9A-F]|[!$&'()*+,;=]|:|@)*)*)|(?P<ipath>))(?:\\?(?P<iquery>(?:(?:(?:[a-zA-Z0-9.
_~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U000
2fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\
U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a00
00-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U00
0e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)|[\ue000-\uf8ff\U000f000
0-\U000ffffd\U00100000-\U0010fffd]|/|\\?)*))?(?:\\#(?P<ifragment>(?:(?:(?:[a-zA-
Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-
\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060
000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U0
00a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfff
d\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)|/|\\?)*))?)

一行：

(?P<scheme>[a-zA-Z][a-zA-Z0-9+.-]*):(?://(?P<iauthority>(?:(?P<iuserinfo>(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:)*)@)?(?P<ihost>\\[(?:(?:[0-9A-F]{1,4}:){6}(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|::(?:[0-9A-F]{1,4}:){5}(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|[0-9A-F]{1,4}?::(?:[0-9A-F]{1,4}:){4}(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|(?:(?:[0-9A-F]{1,4}:)?[0-9A-F]{1,4})?::(?:[0-9A-F]{1,4}:){3}(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|(?:(?:[0-9A-F]{1,4}:){,2}[0-9A-F]{1,4})?::(?:[0-9A-F]{1,4}:){2}(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|(?:(?:[0-9A-F]{1,4}:){,3}[0-9A-F]{1,4})?::(?:[0-9A-F]{1,4}:)(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|(?:(?:[0-9A-F]{1,4}:){,4}[0-9A-F]{1,4})?::(?:[0-9A-F]{1,4}:[0-9A-F]{1,4}|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)))|(?:(?:[0-9A-F]{1,4}:){,5}[0-9A-F]{1,4})?::[0-9A-F]{1,4}|(?:(?:[0-9A-F]{1,4}:){,6}[0-9A-F]{1,4})?::|v[0-9A-F]+\\.(?:[a-zA-Z0-9_.~-]|[!$&'()*+,;=]|:)+)\\]|(?:(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))|(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=])*)(?::(?P<port>[0-9]*))?)(?P<ipath>(?:/(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)*)*)|(?P<ipath>/(?:(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)+(?:/(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)*)*)?)|(?P<ipath>(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)+(?:/(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)*)*)|(?P<ipath>))(?:\\?(?P<iquery>(?:(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U00030000-\U0003fffd\U00040000-\U0004fffd\U00050000-\U0005fffd\U00060000-\U0006fffd\U00070000-\U0007fffd\U00080000-\U0008fffd\U00090000-\U0009fffd\U000a0000-\U000afffd\U000b0000-\U000bfffd\U000c0000-\U000cfffd\U000d0000-\U000dfffd\U000e1000-\U000efffd])|%[0-9A-F][0-9A-F]|[!$&'()*+,;=]|:|@)|[\ue000-\uf8ff\U000f0000-\U000ffffd\U00100000-\U0010fffd]|/|\\?)*))?(?:\\#(?P<ifragment>(?:(?:(?:[a-zA-Z0-9._~-]|[\xa0-\ud7ff\uf900-\ufdcf\ufdf0-\uffef\U00010000-\U0001fffd\U00020000-\U0002fffd\U0003000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注意 -Lepl不再受到维护或支持。

RFC 3696定义了URL验证的“最佳做法”-http: //www.faqs.org/rfcs/rfc3696.html

Lepl的最新版本（Python解析器库）包括RFC 3696的实现。您可以使用类似以下的方式：

from lepl.apps.rfc3696 import Email, HttpUrl

# compile the validators (do once at start of program)
valid_email = Email()
valid_http_url = HttpUrl()

# use the validators (as often as you like)
if valid_email(some_email):
    # email is ok
else:
    # email is bad
if valid_http_url(some_url):
    # url is ok
else:
    # url is bad

尽管验证器是在Lepl中定义的，Lepl是递归下降解析器，但它们很大程度上在内部编译为正则表达式。它结合了两全其美的优点-（相对）易于阅读的定义，可以根据RFC 3696 和有效的实现进行检查。我的博客上有一篇文章显示了如何简化解析器-http: //www.acooke.org/cute/LEPLOptimi0.html

Lepl可以在http://www.acooke.org/lepl上获得，RFC 3696模块在http://www.acooke.org/lepl/rfc3696.html上可以找到。

这是此版本中的全新内容，因此可能包含错误。如果您有任何问题，请与我联系，我会尽快修复。谢谢。

如今，在90％的情况下，如果您在Python中使用URL，则可能使用python-requests。因此，这里的问题是-为什么不重用请求中的URL验证？

from requests.models import PreparedRequest
import requests.exceptions


def check_url(url):
    prepared_request = PreparedRequest()
    try:
        prepared_request.prepare_url(url, None)
        return prepared_request.url
    except requests.exceptions.MissingSchema, e:
        raise SomeException

特征：

• 不要重新发明轮子
• 干燥
• 离线办公
• 最少的资源

提供的正则表达式应与http://www.ietf.org/rfc/rfc3986.txt格式的任何网址匹配；并且在python解释器中进行测试时会执行。

您遇到解析困难的网址使用哪种格式？

这些年来，我需要做很多次，并且总是以模仿别人正则表达式的方式复制自己，而正则表达式的思考方式比我想的要多。

话虽如此，Django表单代码中有一个正则表达式可以解决这个问题：

http://code.djangoproject.com/browser/django/trunk/django/forms/fields.py#L534

修改后的Django URL验证正则表达式：

import re

ul = '\u00a1-\uffff'  # unicode letters range (must not be a raw string)

# IP patterns 
ipv4_re = r'(?:25[0-5]|2[0-4]\d|[0-1]?\d?\d)(?:\.(?:25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}' 
ipv6_re = r'\[[0-9a-f:\.]+\]'

# Host patterns 
hostname_re = r'[a-z' + ul + r'0-9](?:[a-z' + ul + r'0-9-]{0,61}[a-z' + ul + r'0-9])?'
domain_re = r'(?:\.(?!-)[a-z' + ul + r'0-9-]{1,63}(?<!-))*' # domain names have max length of 63 characters
tld_re = ( 
    r'\.'                                # dot 
    r'(?!-)'                             # can't start with a dash 
    r'(?:[a-z' + ul + '-]{2,63}'         # domain label 
    r'|xn--[a-z0-9]{1,59})'              # or punycode label 
    r'(?<!-)'                            # can't end with a dash 
    r'\.?'                               # may have a trailing dot 
) 
host_re = '(' + hostname_re + domain_re + tld_re + '|localhost)'

regex = re.compile( 
    r'^(?:http|ftp)s?://' # http(s):// or ftp(s)://
    r'(?:\S+(?::\S*)?@)?'  # user:pass authentication 
    r'(?:' + ipv4_re + '|' + ipv6_re + '|' + host_re + ')' # localhost or ip
    r'(?::\d{2,5})?'  # optional port
    r'(?:[/?#][^\s]*)?'  # resource path
    r'\Z', re.IGNORECASE)

来源：https : //github.com/django/django/blob/master/django/core/validators.py#L74

urlfinders = [
    re.compile("([0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}|(((news|telnet|nttp|file|http|ftp|https)://)|(www|ftp)[-A-Za-z0-9]*\\.)[-A-Za-z0-9\\.]+)(:[0-9]*)?/[-A-Za-z0-9_\\$\\.\\+\\!\\*\\(\\),;:@&=\\?/~\\#\\%]*[^]'\\.}>\\),\\\"]"),
    re.compile("([0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}|(((news|telnet|nttp|file|http|ftp|https)://)|(www|ftp)[-A-Za-z0-9]*\\.)[-A-Za-z0-9\\.]+)(:[0-9]*)?"),
    re.compile("(~/|/|\\./)([-A-Za-z0-9_\\$\\.\\+\\!\\*\\(\\),;:@&=\\?/~\\#\\%]|\\\\
)+"),
    re.compile("'\\<((mailto:)|)[-A-Za-z0-9\\.]+@[-A-Za-z0-9\\.]+"),
]

注意：在您的浏览器中看起来很丑陋，只需复制粘贴即可，并且格式应该很好

在python邮件列表中找到并用于gnome-terminal

来源：http : //mail.python.org/pipermail/python-list/2007-January/595436.html