Question

我正在使用Mechanize下载文件，在响应头中有一个字符串：

Content-Disposition: attachment; filename=myfilename.txt

是否有快速标准的方法来获取该文件名值？我现在想到的是：

filename = f[1]['Content-Disposition'].split('; ')[1].replace('filename=', '')

但它看起来像是一个快速的肮脏解决方案。

Answer 1

首先使用mechanize获取标头的值，然后使用内置的cgi模块解析标头。

演示：

>>> import mechanize
>>> browser = mechanize.Browser()
>>> response = browser.open('http://example.com/your/url')
>>> info = response.info()
>>> header = info.getheader('Content-Disposition')
>>> header
'attachment; filename=myfilename.txt'

然后可以解析标头值：

>>> import cgi               
>>> value, params = cgi.parse_header(header)
>>> value
'attachment'
>>> params
{'filename': 'myfilename.txt'}

params是一个简单的字典，因此您需要params['filename']。文件名是否用引号括起来并不重要。

Answer 2

这些正则表达式基于RFC 6266的语法，但经过修改以接受没有处置类型的标题，例如： Content-Disposition：filename = example.html

即。 [disposition-type“;” ] disposition-parm（“;”disposition-parm）* / disposition-type

它将使用和不使用引号处理文件名参数，并从引号中的值中取消引用引用的对，例如filename =“foo \”bar“ - ＆gt; foo”bar

它将处理filename *扩展参数，并且更喜欢文件名*扩展参数而不管它们在标题中出现的顺序

它剥离文件夹名称信息，例如/ etc / passwd - ＆gt; passwd，默认为URL路径中的basename，缺少filename参数（或标题，或者如果参数值为空字符串）

token和qdtext正则表达式基于RFC 2616的语法，mimeCharset和valueChars正则表达式基于RFC 5987的语法，语言正则表达式基于RFC 5646的语法

import re, urllib
from os import path
from urlparse import urlparse

# content-disposition = "Content-Disposition" ":"
#                        disposition-type *( ";" disposition-parm )
# disposition-type    = "inline" | "attachment" | disp-ext-type
#                     ; case-insensitive
# disp-ext-type       = token
# disposition-parm    = filename-parm | disp-ext-parm
# filename-parm       = "filename" "=" value
#                     | "filename*" "=" ext-value
# disp-ext-parm       = token "=" value
#                     | ext-token "=" ext-value
# ext-token           = <the characters in token, followed by "*">

token = '[-!#-\'*+.\dA-Z^-z|~]+'
qdtext='[]-~\t !#-[]'
mimeCharset='[-!#-&+\dA-Z^-z]+'
language='(?:[A-Za-z]{2,3}(?:-[A-Za-z]{3}(?:-[A-Za-z]{3}){,2})?|[A-Za-z]{4,8})(?:-[A-Za-z]{4})?(?:-(?:[A-Za-z]{2}|\d{3}))(?:-(?:[\dA-Za-z]{5,8}|\d[\dA-Za-z]{3}))*(?:-[\dA-WY-Za-wy-z](?:-[\dA-Za-z]{2,8})+)*(?:-[Xx](?:-[\dA-Za-z]{1,8})+)?|[Xx](?:-[\dA-Za-z]{1,8})+|[Ee][Nn]-[Gg][Bb]-[Oo][Ee][Dd]|[Ii]-[Aa][Mm][Ii]|[Ii]-[Bb][Nn][Nn]|[Ii]-[Dd][Ee][Ff][Aa][Uu][Ll][Tt]|[Ii]-[Ee][Nn][Oo][Cc][Hh][Ii][Aa][Nn]|[Ii]-[Hh][Aa][Kk]|[Ii]-[Kk][Ll][Ii][Nn][Gg][Oo][Nn]|[Ii]-[Ll][Uu][Xx]|[Ii]-[Mm][Ii][Nn][Gg][Oo]|[Ii]-[Nn][Aa][Vv][Aa][Jj][Oo]|[Ii]-[Pp][Ww][Nn]|[Ii]-[Tt][Aa][Oo]|[Ii]-[Tt][Aa][Yy]|[Ii]-[Tt][Ss][Uu]|[Ss][Gg][Nn]-[Bb][Ee]-[Ff][Rr]|[Ss][Gg][Nn]-[Bb][Ee]-[Nn][Ll]|[Ss][Gg][Nn]-[Cc][Hh]-[Dd][Ee]'
valueChars = '(?:%[\dA-F][\dA-F]|[-!#$&+.\dA-Z^-z|~])*'
dispositionParm = '[Ff][Ii][Ll][Ee][Nn][Aa][Mm][Ee]\s*=\s*(?:({token})|"((?:{qdtext}|\\\\[\t !-~])*)")|[Ff][Ii][Ll][Ee][Nn][Aa][Mm][Ee]\*\s*=\s*({mimeCharset})\'(?:{language})?\'({valueChars})|{token}\s*=\s*(?:{token}|"(?:{qdtext}|\\\\[\t !-~])*")|{token}\*\s*=\s*{mimeCharset}\'(?:{language})?\'{valueChars}'.format(**locals())

try:
  m = re.match('(?:{token}\s*;\s*)?(?:{dispositionParm})(?:\s*;\s*(?:{dispositionParm}))*|{token}'.format(**locals()), result.headers['Content-Disposition'])

except KeyError:
  name = path.basename(urllib.unquote(urlparse(url).path))

else:
  if not m:
    name = path.basename(urllib.unquote(urlparse(url).path))

  # Many user agent implementations predating this specification do not
  # understand the "filename*" parameter.  Therefore, when both "filename"
  # and "filename*" are present in a single header field value, recipients
  # SHOULD pick "filename*" and ignore "filename"

  elif m.group(8) is not None:
    name = urllib.unquote(m.group(8)).decode(m.group(7))

  elif m.group(4) is not None:
    name = urllib.unquote(m.group(4)).decode(m.group(3))

  elif m.group(6) is not None:
    name = re.sub('\\\\(.)', '\1', m.group(6))

  elif m.group(5) is not None:
    name = m.group(5)

  elif m.group(2) is not None:
    name = re.sub('\\\\(.)', '\1', m.group(2))

  else:
    name = m.group(1)

  # Recipients MUST NOT be able to write into any location other than one to
  # which they are specifically entitled

  if name:
    name = path.basename(name)

  else:
    name = path.basename(urllib.unquote(urlparse(url).path))

Answer 3

我会尝试类似的事情：

import re
filename = re.findall("filename=(\S+)", f[1]['Content-Disposition'])

它处理文件名上的引号和URL转义。

如何从标题中的Content-Disposition获取文件名

3 个答案: