1 #

     2 # Copyright (c) 2008-2015 Thierry Florac <tflorac AT ulthar.net>

     3 # All Rights Reserved.

     4 #

     5 # This software is subject to the provisions of the Zope Public License,

     6 # Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.

     7 # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED

     8 # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

     9 # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS

    10 # FOR A PARTICULAR PURPOSE.

    11 #

    12 

    13 __docformat__ = 'restructuredtext'

    14 

    15 

    16 # import standard library

    17 

    18 # import interfaces

    19 

    20 # import packages

    21 

    22 

    23 def normalize_lang(lang):

    24     lang = lang.strip().lower()

    25     lang = lang.replace('_', '-')

    26     lang = lang.replace(' ', '')

    27     return lang

    28 

    29 

    30 def get_browser_language(request):

    31     """Custom locale negotiator

    32 

    33     Copied from zope.publisher code

    34     """

    35     accept_langs = request.headers.get('Accept-Language', '').split(',')

    36 

    37     # Normalize lang strings

    38     accept_langs = [normalize_lang(l) for l in accept_langs]

    39     # Then filter out empty ones

    40     accept_langs = [l for l in accept_langs if l]

    41 

    42     accepts = []

    43     for index, lang in enumerate(accept_langs):

    44         l = lang.split(';', 2)

    45 

    46         # If not supplied, quality defaults to 1...

    47         quality = 1.0

    48 

    49         if len(l) == 2:

    50             q = l[1]

    51             if q.startswith('q='):

    52                 q = q.split('=', 2)[1]

    53                 try:

    54                     quality = float(q)

    55                 except ValueError:

    56                     # malformed quality value, skip it.

    57                     continue

    58 

    59         if quality == 1.0:

    60             # ... but we use 1.9 - 0.001 * position to

    61             # keep the ordering between all items with

    62             # 1.0 quality, which may include items with no quality

    63             # defined, and items with quality defined as 1.

    64             quality = 1.9 - (0.001 * index)

    65 

    66         accepts.append((quality, l[0]))

    67 

    68     # Filter langs with q=0, which means

    69     # unwanted lang according to the spec

    70     # See: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4

    71     accepts = [acc for acc in accepts if acc[0]]

    72 

    73     accepts.sort()

    74     accepts.reverse()

    75 

    76     return [lang for qual, lang in accepts][0] if accepts else None