def secure_filename(filename):
    r"""Borrowed from :mod:`werkzeug.utils`, under the BSD 3-clause license.

    Pass it a filename and it will return a secure version of it.  This
    filename can then safely be stored on a regular file system and passed
    to :func:`os.path.join`.  The filename returned is an ASCII only string
    for maximum portability.

    On windows systems the function also makes sure that the file is not
    named after one of the special device files.

    >>> secure_filename("My cool movie.mov")
    'My_cool_movie.mov'
    >>> secure_filename("../../../etc/passwd")
    'etc_passwd'
    >>> secure_filename(u'i contain cool \xfcml\xe4uts.txt')
    'i_contain_cool_umlauts.txt'

    The function might return an empty filename.  It's your responsibility
    to ensure that the filename is unique and that you generate random
    filename if the function returned an empty one.

    :param filename: the filename to secure
    """
    _filename_ascii_strip_re = re.compile(r'[^A-Za-z0-9_.-]')
    _windows_device_files = ('CON', 'AUX', 'COM1', 'COM2', 'COM3', 'COM4',
                             'LPT1', 'LPT2', 'LPT3', 'PRN', 'NUL')
    if isinstance(filename, text_type):
        from unicodedata import normalize
        filename = normalize('NFKD', filename).encode('ascii', 'ignore')
        if not PY2:
            filename = filename.decode('ascii')
    for sep in os.path.sep, os.path.altsep:
        if sep:
            filename = filename.replace(sep, ' ')
    filename = str(_filename_ascii_strip_re.sub('', '_'.join(
                   filename.split()))).strip('._')

    # on nt a couple of special files are present in each folder.  We
    # have to ensure that the target file is not such a filename.  In
    # this case we prepend an underline
    if os.name == 'nt' and filename and \
       filename.split('.')[0].upper() in _windows_device_files:
        filename = '_' + filename

    return filename
def testProvenanceItemMetadata(self):
        """
        Test item provenance endpoint with metadata and basic changes
        """
        item = self.item1
        user = self.user
        admin = self.admin

        # check that the first version of the item exists
        # ensure version 1, created by admin user, with creation event
        self._checkProvenance(None, item, 1, admin, 'creation')

        # update meta to {x:y}
        metadata1 = {'x': 'y'}
        resp = self._getProvenanceAfterMetadata(item, metadata1, admin)
        # ensure version 2, updated by admin user, with update event, and meta
        # in provenance matches
        self._checkProvenance(resp, item, 2, admin, 'update',
                              {'new': {'meta': metadata1}})

        # update meta to {} by regular user, we have to send in the key to
        # remove it but check the saved metadata against {}
        metadata2 = {'x': None}
        resp = self._getProvenanceAfterMetadata(item, metadata2, user)
        # ensure version 3, updated by regular user, with update event, and
        # meta in provenance matches
        self._checkProvenance(resp, item, 3, user, 'update',
                              {'old': {'meta': metadata1},
                               'new': {'meta': {}}})

        # update meta to {x:y} by regular user
        metadata3 = {'x': 'y'}
        resp = self._getProvenanceAfterMetadata(item, metadata3, user)
        # ensure version 4, updated by regular user, with update event, and
        # meta in provenance matches
        self._checkProvenance(resp, item, 4, user, 'update',
                              {'old': {'meta': {}},
                               'new': {'meta': metadata3}})

        # update meta to {x:z} by regular user
        metadata4 = {'x': 'z'}
        resp = self._getProvenanceAfterMetadata(item, metadata4, user)
        # ensure version 5, updated by regular user, with update event, and
        # meta in provenance matches
        self._checkProvenance(resp, item, 5, user, 'update',
                              {'old': {'meta': metadata3},
                               'new': {'meta': metadata4}})

        # update meta to {x:z, q:u} by regular user
        metadata5 = {'x': 'z', 'q': 'u'}
        resp = self._getProvenanceAfterMetadata(item, metadata5, user)
        # ensure version 6, updated by regular user, with update event, and
        # meta in provenance matches
        self._checkProvenance(resp, item, 6, user, 'update',
                              {'old': {'meta': metadata4},
                               'new': {'meta': metadata5}})

        # update meta to {q:a} by regular user
        metadata6 = {'x': None, 'q': 'a'}
        resp = self._getProvenanceAfterMetadata(item, metadata6, user)
        # ensure version 7, updated by regular user, with update event, and
        # meta in provenance matches
        self._checkProvenance(resp, item, 7, user, 'update',
                              {'old': {'meta': metadata5},
                               'new': {'meta': {'q': 'a'}}})

        # Change the item name and description
        params = {'name': 'Renamed object', 'description': 'New description'}
        resp = self.request(path='/item/%s' % item['_id'], method='PUT',
                            user=admin, params=params)
        self.assertStatusOk(resp)
        params['lowerName'] = params['name'].lower()
        self._checkProvenance(None, item, 8, admin, 'update', {'new': params})

        # Copy the item and check that we marked it as copied
        params = {'name': 'Copied object'}
        resp = self.request(path='/item/%s/copy' % item['_id'],
                            method='POST', user=admin, params=params)
        self.assertStatusOk(resp)
        newItem = resp.json
        self._checkProvenance(None, newItem, 9, admin, 'copy',
                              {'originalId': str(item['_id'])})