检测字符串中的URL并使用"<a href ..."标记进行换行

Question

我希望写一些似乎应该很容易的东西,但无论出于什么原因,我都很难理解它.

我正在寻找一个python函数,当传递一个字符串时,将传递该字符串与HTML编码围绕URL.

unencoded_string = "This is a link - http://google.com"

def encode_string_with_links(unencoded_string):
    # some sort of regex magic occurs
    return encoded_string

print encoded_string

'This is a link - <a href="http://google.com">http://google.com</a>'

谢谢!

Answer 1

你需要的"正则表达式魔术"只是sub(它做了替代):

def encode_string_with_links(unencoded_string):
  return URL_REGEX.sub(r'<a href="\1">\1</a>', unencoded_string)

URL_REGEX 可能是这样的:

URL_REGEX = re.compile(r'''((?:mailto:|ftp://|http://)[^ <>'"{}|\\^`[\]]*)''')

这是一个非常宽松的URL正则表达式:它允许使用mailto,http和ftp方案,之后几乎只会继续运行直到它遇到"不安全"的字符(除了你想要允许转义的百分比).如果需要,你可以更严格.例如,您可以要求百分比后跟有效的十六进制转义,或者只允许一个磅符号(对于片段)或强制查询参数和片段之间的顺序.不过,这应该足以让你入门.

Answer 2

谷歌搜索解决方案:

#---------- find_urls.py----------#
# Functions to identify and extract URLs and email addresses

import re

def fix_urls(text):
    pat_url = re.compile(  r'''
                     (?x)( # verbose identify URLs within text
         (http|ftp|gopher) # make sure we find a resource type
                       :// # ...needs to be followed by colon-slash-slash
            (\w+[:.]?){2,} # at least two domain groups, e.g. (gnosis.)(cx)
                      (/?| # could be just the domain name (maybe w/ slash)
                [^ \n\r"]+ # or stuff then space, newline, tab, quote
                    [\w/]) # resource name ends in alphanumeric or slash
         (?=[\s\.,>)'"\]]) # assert: followed by white or clause ending
                         ) # end of match group
                           ''')
    pat_email = re.compile(r'''
                    (?xm)  # verbose identify URLs in text (and multiline)
                 (?=^.{11} # Mail header matcher
         (?<!Message-ID:|  # rule out Message-ID's as best possible
             In-Reply-To)) # ...and also In-Reply-To
                    (.*?)( # must grab to email to allow prior lookbehind
        ([A-Za-z0-9-]+\.)? # maybe an initial part: DAVID.mertz@gnosis.cx
             [A-Za-z0-9-]+ # definitely some local user: MERTZ@gnosis.cx
                         @ # ...needs an at sign in the middle
              (\w+\.?){2,} # at least two domain groups, e.g. (gnosis.)(cx)
         (?=[\s\.,>)'"\]]) # assert: followed by white or clause ending
                         ) # end of match group
                           ''')

    for url in re.findall(pat_url, text):
       text = text.replace(url[0], '<a href="%(url)s">%(url)s</a>' % {"url" : url[0]})

    for email in re.findall(pat_email, text):
       text = text.replace(email[1], '<a href="mailto:%(email)s">%(email)s</a>' % {"email" : email[1]})

    return text

if __name__ == '__main__':
    print fix_urls("test http://google.com asdasdasd some more text")

编辑:调整您的需求