Python：获取URL路径部分

Question

如何从网址获取特定路径部分？例如，我想要一个对此进行操作的函数：

http://www.mydomain.com/hithere?image=2934

并返回“hithere”

或对此进行操作：

http://www.mydomain.com/hithere/something/else

并返回相同的内容（“hithere”）

我知道这可能会使用urllib或urllib2，但我无法从文档中找出如何仅获取路径的一部分。

Answer 1

使用urlparse提取网址的路径组件：

>>> import urlparse
>>> path = urlparse.urlparse('http://www.example.com/hithere/something/else').path
>>> path
'/hithere/something/else'

使用os.path将路径拆分为组件.split：

>>> import os.path
>>> os.path.split(path)
('/hithere/something', 'else')

dirname和basename函数为你提供了两个分割;也许在while循环中使用dirname：

>>> while os.path.dirname(path) != '/':
...     path = os.path.dirname(path)
... 
>>> path
'/hithere'

Answer 2

最佳选择是在使用URL的路径组件时使用posixpath模块。此模块与os.path具有相同的接口，并且在基于POSIX和Windows NT的平台上使用时，始终在POSIX路径上运行。

---

示例代码：

#!/usr/bin/env python3

import urllib.parse
import sys
import posixpath
import ntpath
import json

def path_parse( path_string, *, normalize = True, module = posixpath ):
    result = []
    if normalize:
        tmp = module.normpath( path_string )
    else:
        tmp = path_string
    while tmp != "/":
        ( tmp, item ) = module.split( tmp )
        result.insert( 0, item )
    return result

def dump_array( array ):
    string = "[ "
    for index, item in enumerate( array ):
        if index > 0:
            string += ", "
        string += "\"{}\"".format( item )
    string += " ]"
    return string

def test_url( url, *, normalize = True, module = posixpath ):
    url_parsed = urllib.parse.urlparse( url )
    path_parsed = path_parse( urllib.parse.unquote( url_parsed.path ),
        normalize=normalize, module=module )
    sys.stdout.write( "{}\n  --[n={},m={}]-->\n    {}\n".format( 
        url, normalize, module.__name__, dump_array( path_parsed ) ) )

test_url( "http://eg.com/hithere/something/else" )
test_url( "http://eg.com/hithere/something/else/" )
test_url( "http://eg.com/hithere/something/else/", normalize = False )
test_url( "http://eg.com/hithere/../else" )
test_url( "http://eg.com/hithere/../else", normalize = False )
test_url( "http://eg.com/hithere/../../else" )
test_url( "http://eg.com/hithere/../../else", normalize = False )
test_url( "http://eg.com/hithere/something/./else" )
test_url( "http://eg.com/hithere/something/./else", normalize = False )
test_url( "http://eg.com/hithere/something/./else/./" )
test_url( "http://eg.com/hithere/something/./else/./", normalize = False )

test_url( "http://eg.com/see%5C/if%5C/this%5C/works", normalize = False )
test_url( "http://eg.com/see%5C/if%5C/this%5C/works", normalize = False,
    module = ntpath )

---

代码输出：

http://eg.com/hithere/something/else
  --[n=True,m=posixpath]-->
    [ "hithere", "something", "else" ]
http://eg.com/hithere/something/else/
  --[n=True,m=posixpath]-->
    [ "hithere", "something", "else" ]
http://eg.com/hithere/something/else/
  --[n=False,m=posixpath]-->
    [ "hithere", "something", "else", "" ]
http://eg.com/hithere/../else
  --[n=True,m=posixpath]-->
    [ "else" ]
http://eg.com/hithere/../else
  --[n=False,m=posixpath]-->
    [ "hithere", "..", "else" ]
http://eg.com/hithere/../../else
  --[n=True,m=posixpath]-->
    [ "else" ]
http://eg.com/hithere/../../else
  --[n=False,m=posixpath]-->
    [ "hithere", "..", "..", "else" ]
http://eg.com/hithere/something/./else
  --[n=True,m=posixpath]-->
    [ "hithere", "something", "else" ]
http://eg.com/hithere/something/./else
  --[n=False,m=posixpath]-->
    [ "hithere", "something", ".", "else" ]
http://eg.com/hithere/something/./else/./
  --[n=True,m=posixpath]-->
    [ "hithere", "something", "else" ]
http://eg.com/hithere/something/./else/./
  --[n=False,m=posixpath]-->
    [ "hithere", "something", ".", "else", ".", "" ]
http://eg.com/see%5C/if%5C/this%5C/works
  --[n=False,m=posixpath]-->
    [ "see\", "if\", "this\", "works" ]
http://eg.com/see%5C/if%5C/this%5C/works
  --[n=False,m=ntpath]-->
    [ "see", "if", "this", "works" ]

---

注意：

• 在基于Windows NT的平台os.path上是ntpath
• 在基于Unix / Posix的平台os.path上是posixpath
• ntpath无法正确处理反斜杠（\）（请参阅代码/输出中的最后两种情况） - 这就是推荐使用posixpath的原因。
• 请记得使用urllib.parse.unquote
• 考虑使用posixpath.normpath
• RFC 3986未定义多个路径分隔符（/）的语义。但是，posixpath会折叠多个相邻的路径分隔符（即它会同时处理///，//和/）
• 尽管POSIX和URL路径具有相似的语法和语义，但它们并不完全相同。

---

规范性参考文献：

• IEEE Std 1003.1, 2013 - Vol. 1: Base Definitions - Section 4.12: Pathname Resolution
• The GNU C Library Reference Manual - Section 11.2: File Names
• IETF RFC 3986: Uniform Resource Identifier (URI): Generic Syntax - Section 3.3: Path
• IETF RFC 3986: Uniform Resource Identifier (URI): Generic Syntax - Section 6: Normalization and Comparison
• Wikipedia: URL normalization

Answer 3

Python 3.4+解决方案：

from urllib.parse import unquote, urlparse
from pathlib import PurePosixPath

url = 'http://www.example.com/hithere/something/else'

PurePosixPath(
    unquote(
        urlparse(
            url
        ).path
    )
).parts[1]

# returns 'hithere' (the same for the URL with parameters)

# parts holds ('/', 'hithere', 'something', 'else')
#               0    1          2            3

Answer 4

Python3导入中的注释已更改为from urllib.parse import urlparse，请参见documentation。这是一个示例：

>>> from urllib.parse import urlparse
>>> url = 's3://bucket.test/my/file/directory'
>>> p = urlparse(url)
>>> p
ParseResult(scheme='s3', netloc='bucket.test', path='/my/file/directory', params='', query='', fragment='')
>>> p.scheme
's3'
>>> p.netloc
'bucket.test'
>>> p.path
'/my/file/directory'

Answer 5

urlparse和os.path.split的组合将起到作用。以下脚本将列表的所有部分存储在列表中，向后。

import os.path, urlparse

def generate_sections_of_url(url):
    path = urlparse.urlparse(url).path
    sections = []; temp = "";
    while path != '/':
        temp = os.path.split(path)
        path = temp[0]
        sections.append(temp[1])
    return sections

这将返回：[＆＃34; else＆＃34;，＆＃34;某事＆＃34;，＆＃34; hithere＆＃34;]

Answer 6

以下是使用urlparse和rpartition的示例。

# Python 2x:
from urlparse import urlparse
# Python 3x:
from urllib.parse import urlparse

def printPathTokens(full_url):
    print('printPathTokens() called: %s' % full_url)

    p_full = urlparse(full_url).path

    print(' . p_full url: %s' % p_full)

    # Split the path using rpartition method of string
    # rpartition "returns a tuple containing the part the before separator,
    # argument string and the part after the separator" 
    (rp_left, rp_match, rp_right) = p_full.rpartition('/')

    if rp_match == '': # returns the rpartition separator if found
        print(' . No slashes found in path')
    else:
        print(' . path to last resource: %s' % rp_left)
        if rp_right == '': # Ended with a slash
            print(' . last resource: (none)')
        else:
            print(' . last resource: %s' % (rp_right))


printPathTokens('http://www.example.com/temp/something/happen/index.html')
# Output:
# printPathTokens() called: http://www.example.com/temp/something/happen/index.html
# . p_full url: /temp/something/happen/index.html
# . path to last resource: /temp/something/happen
# . last resource: index.html

printPathTokens('http://www.example.com/temp/something/happen/')
# Output:
# printPathTokens() called: http://www.example.com/temp/something/happen/
# . p_full url: /temp/something/happen/
# . path to last resource: /temp/something/happen
# . last resource: (none)

printPathTokens('http://www.example.com/temp/something/happen')
# Output:
# printPathTokens() called: http://www.example.com/temp/something/happen
# . p_full url: /temp/something/happen
# . path to last resource: /temp/something
# . last resource: happen