from?__future__?import?absolute_import
import?email.utils
import?mimetypes

from?.packages?import?six


def?guess_content_type（filename?default=‘a(chǎn)pplication/octet-stream‘）:
????“““
????Guess?the?“Content-Type“?of?a?file.
????:param?filename:
????????The?filename?to?guess?the?“Content-Type“?of?using?:mod:‘mimetypes‘.
????:param?default:
????????If?no?“Content-Type“?can?be?guessed?default?to?‘default‘.
????“““
????if?filename:
????????return?mimetypes.guess_type（filename）[0]?or?default
????return?default


def?format_header_param（name?value）:
????“““
????Helper?function?to?format?and?quote?a?single?header?parameter.
????Particularly?useful?for?header?parameters?which?might?contain
????non-ASCII?values?like?file?names.?This?follows?RFC?2231?as
????suggested?by?RFC?2388?Section?4.4.
????:param?name:
????????The?name?of?the?parameter?a?string?expected?to?be?ASCII?only.
????:param?value:
????????The?value?of?the?parameter?provided?as?a?unicode?string.
????“““
????if?not?any（ch?in?value?for?ch?in?‘“\\\r\n‘）:
????????result?=?‘%s=“%s“‘?%?（name?value）
????????try:
????????????result.encode（‘a(chǎn)scii‘）
????????except?UnicodeEncodeError:
????????????pass
????????else:
????????????return?result
????if?not?six.PY3:??#?Python?2:
????????value?=?value.encode（‘utf-8‘）
????value?=?email.utils.encode_rfc2231（value?‘utf-8‘）
????#?value?=?‘%s*=%s‘?%?（name?value）
????value?=?‘%s=“%s“‘?%?（name?value.decode（‘utf8‘））
????return?value


class?RequestField（object）:
????“““
????A?data?container?for?request?body?parameters.
????:param?name:
????????The?name?of?this?request?field.
????:param?data:
????????The?data/value?body.
????:param?filename:
????????An?optional?filename?of?the?request?field.
????:param?headers:
????????An?optional?dict-like?object?of?headers?to?initially?use?for?the?field.
????“““
????def?__init__（self?name?data?filename=None?headers=None）:
????????self._name?=?name
????????self._filename?=?filename
????????self.data?=?data
????????self.headers?=?{}
????????if?headers:
????????????self.headers?=?dict（headers）

????@classmethod
????def?from_tuples（cls?fieldname?value）:
????????“““
????????A?:class:‘~urllib3.fields.RequestField‘?factory?from?old-style?tuple?parameters.
????????Supports?constructing?:class:‘~urllib3.fields.RequestField‘?from
????????parameter?of?key/value?strings?AND?key/filetuple.?A?filetuple?is?a
????????（filename?data?MIME?type）?tuple?where?the?MIME?type?is?optional.
????????For?example::
????????????‘foo‘:?‘bar‘
????????????‘fakefile‘:?（‘foofile.txt‘?‘contents?of?foofile‘）
????????????‘realfile‘:?（‘barfile.txt‘?open（‘realfile‘）.read（））
????????????‘typedfile‘:?（‘bazfile.bin‘?open（‘bazfile‘）.read（）?‘image/jpeg‘）
????????????‘nonamefile‘:?‘contents?of?nonamefile?field‘
????????Field?names?and?filenames?must?be?unicode.
????????“““
????????if?isinstance（value?tuple）:
????????????if?len（value）?==?3:
????????????????filename?data?content_type?=?value
????????????else:
?