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mimetypeutils.py
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Sat, Jul 20, 02:20

mimetypeutils.py
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# -*- coding: utf-8 -*-
##
## This file is part of Invenio.
## Copyright (C) 2013 CERN.
##
## Invenio is free software; you can redistribute it and/or
## modify it under the terms of the GNU General Public License as
## published by the Free Software Foundation; either version 2 of the
## License, or (at your option) any later version.
##
## Invenio is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Invenio; if not, write to the Free Software Foundation, Inc.,
## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
"""
Invenio mimetype helper functions.
Usage example:
TODO
"""
import re
from mimetypes import MimeTypes
from werkzeug import cached_property, LocalProxy
# FIXME rename config variables
from invenio.config import \
CFG_BIBDOCFILE_ADDITIONAL_KNOWN_MIMETYPES, \
CFG_BIBDOCFILE_ADDITIONAL_KNOWN_FILE_EXTENSIONS
try:
import magic
if hasattr(magic, "open"):
CFG_HAS_MAGIC = 1
elif hasattr(magic, "Magic"):
CFG_HAS_MAGIC = 2
except ImportError:
CFG_HAS_MAGIC = 0
_magic_cookies = {}
if CFG_HAS_MAGIC == 1:
def _get_magic_cookies():
"""
@return: a tuple of magic object.
@rtype: (MAGIC_NONE, MAGIC_COMPRESS, MAGIC_MIME, MAGIC_COMPRESS + MAGIC_MIME)
@note: ... not real magic. Just see: man file(1)
"""
thread_id = get_ident()
if thread_id not in _magic_cookies:
_magic_cookies[thread_id] = {
magic.MAGIC_NONE: magic.open(magic.MAGIC_NONE),
magic.MAGIC_COMPRESS: magic.open(magic.MAGIC_COMPRESS),
magic.MAGIC_MIME: magic.open(magic.MAGIC_MIME),
magic.MAGIC_COMPRESS + magic.MAGIC_MIME: magic.open(magic.MAGIC_COMPRESS + magic.MAGIC_MIME),
magic.MAGIC_MIME_TYPE: magic.open(magic.MAGIC_MIME_TYPE),
}
for key in _magic_cookies[thread_id].keys():
_magic_cookies[thread_id][key].load()
return _magic_cookies[thread_id]
elif CFG_HAS_MAGIC == 2:
def _magic_wrapper(local_path, mime=True, mime_encoding=False):
thread_id = get_ident()
if (thread_id, mime, mime_encoding) not in _magic_cookies:
magic_object = _magic_cookies[thread_id, mime, mime_encoding] = magic.Magic(mime=mime, mime_encoding=mime_encoding)
else:
magic_object = _magic_cookies[thread_id, mime, mime_encoding]
return magic_object.from_file(local_path) # pylint: disable=E1103
class LazyMimeCache(object):
@cached_property
def mimes(self):
"""
Returns extended MimeTypes.
"""
_mimes = MimeTypes(strict=False)
_mimes.suffix_map.update({'.tbz2' : '.tar.bz2'})
_mimes.encodings_map.update({'.bz2' : 'bzip2'})
if CFG_BIBDOCFILE_ADDITIONAL_KNOWN_MIMETYPES:
for key, value in CFG_BIBDOCFILE_ADDITIONAL_KNOWN_MIMETYPES.iteritems():
_mimes.add_type(key, value)
del key, value
return _mimes
@cached_property
def extensions(self):
"""
Generate the regular expression to match all the known extensions.
@return: the regular expression.
@rtype: regular expression object
"""
_tmp_extensions = self.mimes.encodings_map.keys() + \
self.mimes.suffix_map.keys() + \
self.mimes.types_map[1].keys() + \
CFG_BIBDOCFILE_ADDITIONAL_KNOWN_FILE_EXTENSIONS
extensions = []
for ext in _tmp_extensions:
if ext.startswith('.'):
extensions.append(ext)
else:
extensions.append('.' + ext)
extensions.sort()
extensions.reverse()
extensions = set([ext.lower() for ext in extensions])
extensions = '\\' + '$|\\'.join(extensions) + '$'
extensions = extensions.replace('+', '\\+')
return re.compile(extensions, re.I)
#: Lazy mime and extensitons cache.
_mime_cache = LazyMimeCache()
#: MimeTypes instance.
_mimes = LocalProxy(lambda: _mime_cache.mimes)
#: Regular expression to recognized extensions.
_extensions = LocalProxy(lambda: _mime_cache.extensions)
## Use only functions bellow in your code:
def file_strip_ext(afile, skip_version=False, only_known_extensions=False, allow_subformat=True):
"""
Strip in the best way the extension from a filename.
>>> file_strip_ext("foo.tar.gz")
'foo'
>>> file_strip_ext("foo.buz.gz")
'foo.buz'
>>> file_strip_ext("foo.buz")
'foo'
>>> file_strip_ext("foo.buz", only_known_extensions=True)
'foo.buz'
>>> file_strip_ext("foo.buz;1", skip_version=False,
... only_known_extensions=True)
'foo.buz;1'
>>> file_strip_ext("foo.gif;icon")
'foo'
>>> file_strip_ext("foo.gif;icon", only_know_extensions=True,
... allow_subformat=False)
'foo.gif;icon'
@param afile: the path/name of a file.
@type afile: string
@param skip_version: whether to skip a trailing ";version".
@type skip_version: bool
@param only_known_extensions: whether to strip out only known extensions or
to consider as extension anything that follows a dot.
@type only_known_extensions: bool
@param allow_subformat: whether to consider also subformats as part of
the extension.
@type allow_subformat: bool
@return: the name/path without the extension (and version).
@rtype: string
"""
import os
afile = afile.split(';')
if len(afile)>1 and allow_subformat and not afile[-1].isdigit():
afile = afile[0:-1]
if len(afile)>1 and skip_version and afile[-1].isdigit():
afile = afile[0:-1]
afile = ';'.join(afile)
nextfile = _extensions.sub('', afile)
if nextfile == afile and not only_known_extensions:
nextfile = os.path.splitext(afile)[0]
while nextfile != afile:
afile = nextfile
nextfile = _extensions.sub('', afile)
return nextfile
def guess_mimetype_and_encoding(afile):
"""
Tries to guess mimetype and encoding of a file.
@param afile: the path/name of a file
@time afile: string
@return: the mimetype and encoding
@rtype: tuple
"""
return _mimes.guess_type(afile)
def guess_extension(amimetype, normalize=False):
"""
Tries to guess extension for a mimetype.
@param amimetype: name of a mimetype
@time amimetype: string
@return: the extension
@rtype: string
"""
ext = _mimes.guess_extension(amimetype)
if ext and normalize:
## Normalize some common magic mis-interpreation
ext = {'.asc': '.txt', '.obj': '.bin'}.get(ext, ext)
from invenio.bibdocfile_normalizer import normalize_format
return normalize_format(ext)
return ext
def get_magic_guesses(fullpath):
"""
Return all the possible guesses from the magic library about
the content of the file.
@param fullpath: location of the file
@type fullpath: string
@return: guesses about content of the file
@rtype: tuple
"""
if CFG_HAS_MAGIC == 1:
magic_cookies = _get_magic_cookies()
magic_result = []
for key in magic_cookies.keys():
magic_result.append(magic_cookies[key].file(fullpath))
return tuple(magic_result)
elif CFG_HAS_MAGIC == 2:
magic_result = []
for key in ({'mime': False, 'mime_encoding': False},
{'mime': True, 'mime_encoding': False},
{'mime': False, 'mime_encoding': True}):
magic_result.append(_magic_wrapper(fullpath, **key))
return tuple(magic_result)
def guess_extension_from_path(local_path):
try:
if CFG_HAS_MAGIC == 1:
magic_cookie = _get_magic_cookies()[magic.MAGIC_MIME_TYPE]
mimetype = magic_cookie.file(local_path)
elif CFG_HAS_MAGIC == 2:
mimetype = _magic_wrapper(local_path, mime=True, mime_encoding=False)
if CFG_HAS_MAGIC:
return guess_extension(mimetype, normalize=True)
except Exception:
pass

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