src/wolnelektury/utils.py

   1 # -*- coding: utf-8 -*-
   2 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
   3 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
   4 #
   5 import json
   6 import os
   7 from functools import wraps
   8
   9 import pytz
  10 from inspect import getargspec
  11
  12 from django.http import HttpResponse
  13 from django.template import RequestContext
  14 from django.template.loader import render_to_string
  15 from django.utils import timezone
  16 from django.conf import settings
  17
  18 tz = pytz.timezone(settings.TIME_ZONE)
  19
  20
  21 def localtime_to_utc(localtime):
  22     return timezone.utc.normalize(
  23         tz.localize(localtime)
  24     )
  25
  26
  27 def utc_for_js(dt):
  28     return dt.strftime('%Y/%m/%d %H:%M:%S UTC')
  29
  30
  31 def makedirs(path):
  32     if not os.path.isdir(path):
  33         os.makedirs(path)
  34
  35
  36 def stringify_keys(dictionary):
  37     return dict((keyword.encode('ascii'), value)
  38                 for keyword, value in dictionary.iteritems())
  39
  40
  41 def json_encode(obj, sort_keys=True, ensure_ascii=False):
  42     return json.dumps(obj, sort_keys=sort_keys, ensure_ascii=ensure_ascii)
  43
  44
  45 def json_decode(obj):
  46     return json.loads(obj)
  47
  48
  49 def json_decode_fallback(value):
  50     try:
  51         return json_decode(value)
  52     except ValueError:
  53         return value
  54
  55
  56 class AjaxError(Exception):
  57     pass
  58
  59
  60 def ajax(login_required=True, method=None, template=None, permission_required=None):
  61     def decorator(fun):
  62         @wraps(fun)
  63         def ajax_view(request):
  64             kwargs = {}
  65             request_params = None
  66             if method == 'post':
  67                 request_params = request.POST
  68             elif method == 'get':
  69                 request_params = request.GET
  70             fun_params, xx, fun_kwargs, defaults = getargspec(fun)
  71             if defaults:
  72                 required_params = fun_params[1:-len(defaults)]
  73             else:
  74                 required_params = fun_params[1:]
  75             missing_params = set(required_params) - set(request_params)
  76             if missing_params:
  77                 res = {
  78                     'result': 'missing params',
  79                     'missing': ', '.join(missing_params),
  80                 }
  81             else:
  82                 if request_params:
  83                     request_params = dict(
  84                         (key, json_decode_fallback(value))
  85                         for key, value in request_params.iteritems()
  86                         if fun_kwargs or key in fun_params)
  87                     kwargs.update(stringify_keys(request_params))
  88                 res = None
  89                 if login_required and not request.user.is_authenticated():
  90                     res = {'result': 'logout'}
  91                 if (permission_required and
  92                         not request.user.has_perm(permission_required)):
  93                     res = {'result': 'access denied'}
  94             if not res:
  95                 try:
  96                     res = fun(request, **kwargs)
  97                     if res and template:
  98                         res = {'html': render_to_string(template, res, RequestContext(request))}
  99                 except AjaxError as e:
 100                     res = {'result': e.args[0]}
 101             if 'result' not in res:
 102                 res['result'] = 'ok'
 103             return HttpResponse(json_encode(res), content_type='application/json; charset=utf-8',
 104                                 status=200 if res['result'] == 'ok' else 400)
 105
 106         return ajax_view
 107
 108     return decorator