src/wolnelektury/utils.py

   1 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
   2 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
   3 #
   4 import codecs
   5 import csv
   6 from functools import wraps
   7 from inspect import getargspec
   8 from io import BytesIO
   9 import json
  10 import os
  11 import re
  12
  13 from django.conf import settings
  14 from django.contrib import admin
  15 from django.core.cache import cache
  16 from django.core.mail import send_mail
  17 from django.http import HttpResponse
  18 from django.template.loader import render_to_string
  19 from django.utils.translation import get_language
  20 from django.conf import settings
  21 from django.utils.safestring import mark_safe
  22 from django.utils.translation import gettext as _
  23
  24
  25 def utc_for_js(dt):
  26     return dt.strftime('%Y/%m/%d %H:%M:%S UTC')
  27
  28
  29 def makedirs(path):
  30     if not os.path.isdir(path):
  31         os.makedirs(path)
  32
  33
  34 def stringify_keys(dictionary):
  35     return dict((keyword.encode('ascii'), value)
  36                 for keyword, value in dictionary.items())
  37
  38
  39 def json_encode(obj, sort_keys=True, ensure_ascii=False):
  40     return json.dumps(obj, sort_keys=sort_keys, ensure_ascii=ensure_ascii)
  41
  42
  43 def json_decode(obj):
  44     return json.loads(obj)
  45
  46
  47 def json_decode_fallback(value):
  48     try:
  49         return json_decode(value)
  50     except ValueError:
  51         return value
  52
  53
  54 class AjaxError(Exception):
  55     pass
  56
  57
  58 def ajax(login_required=False, method=None, template=None, permission_required=None):
  59     def decorator(fun):
  60         @wraps(fun)
  61         def ajax_view(request):
  62             kwargs = {}
  63             request_params = None
  64             if method == 'post':
  65                 request_params = request.POST
  66             elif method == 'get':
  67                 request_params = request.GET
  68             fun_params, xx, fun_kwargs, defaults = getargspec(fun)
  69             if defaults:
  70                 required_params = fun_params[1:-len(defaults)]
  71             else:
  72                 required_params = fun_params[1:]
  73             missing_params = set(required_params) - set(request_params)
  74             if missing_params:
  75                 res = {
  76                     'result': 'missing params',
  77                     'missing': ', '.join(missing_params),
  78                 }
  79             else:
  80                 if request_params:
  81                     request_params = dict(
  82                         (key, json_decode_fallback(value))
  83                         for key, value in request_params.items()
  84                         if fun_kwargs or key in fun_params)
  85                     kwargs.update(stringify_keys(request_params))
  86                 res = None
  87                 if login_required and not request.user.is_authenticated:
  88                     res = {'result': 'logout'}
  89                 if (permission_required and
  90                         not request.user.has_perm(permission_required)):
  91                     res = {'result': 'access denied'}
  92             if not res:
  93                 try:
  94                     res = fun(request, **kwargs)
  95                     if res and template:
  96                         res = {'html': render_to_string(template, res, request=request)}
  97                 except AjaxError as e:
  98                     res = {'result': e.args[0]}
  99             if 'result' not in res:
 100                 res['result'] = 'ok'
 101             return HttpResponse(json_encode(res), content_type='application/json; charset=utf-8',
 102                                 status=200 if res['result'] == 'ok' else 400)
 103
 104         return ajax_view
 105
 106     return decorator
 107
 108
 109 def send_noreply_mail(subject, message, recipient_list, **kwargs):
 110     send_mail(
 111         '[WolneLektury] ' + subject,
 112         message + "\n\n-- \n" + _('Message sent automatically. Please do not reply.'),
 113         'no-reply@wolnelektury.pl', recipient_list, **kwargs)
 114
 115
 116 # source: https://docs.python.org/2/library/csv.html#examples
 117 class UnicodeCSVWriter(object):
 118     """
 119     A CSV writer which will write rows to CSV file "f",
 120     which is encoded in the given encoding.
 121     """
 122
 123     def __init__(self, f, dialect=csv.excel, encoding="utf-8", **kwds):
 124         # Redirect output to a queue
 125         self.queue = BytesIO()
 126         self.writer = csv.writer(self.queue, dialect=dialect, **kwds)
 127         self.stream = f
 128         self.encoder = codecs.getincrementalencoder(encoding)()
 129
 130     def writerow(self, row):
 131         self.writer.writerow([s.encode("utf-8") for s in row])
 132         # Fetch UTF-8 output from the queue ...
 133         data = self.queue.getvalue()
 134         data = data.decode("utf-8")
 135         # ... and reencode it into the target encoding
 136         data = self.encoder.encode(data)
 137         # write to the target stream
 138         self.stream.write(data)
 139         # empty queue
 140         self.queue.truncate(0)
 141
 142     def writerows(self, rows):
 143         for row in rows:
 144             self.writerow(row)
 145
 146
 147 # the original re.escape messes with unicode
 148 def re_escape(s):
 149     return re.sub(r"[(){}\[\].*?|^$\\+-]", r"\\\g<0>", s)
 150
 151
 152 def get_cached_render_key(instance, property_name, language=None):
 153     if language is None:
 154         language = get_language()
 155     return 'cached_render:%s.%s:%s:%s' % (
 156             type(instance).__name__,
 157             property_name,
 158             instance.pk,
 159             language
 160         )
 161
 162
 163 def cached_render(template_name, timeout=24 * 60 * 60):
 164     def decorator(method):
 165         @wraps(method)
 166         def wrapper(self):
 167             key = get_cached_render_key(self, method.__name__)
 168             content = cache.get(key)
 169             if content is None:
 170                 context = method(self)
 171                 content = render_to_string(template_name, context)
 172                 cache.set(key, str(content), timeout=timeout)
 173             else:
 174                 content = mark_safe(content)
 175             return content
 176         return wrapper
 177     return decorator
 178
 179
 180 def clear_cached_renders(bound_method):
 181     for lc, ln in settings.LANGUAGES:
 182         cache.delete(
 183             get_cached_render_key(
 184                 bound_method.__self__,
 185                 bound_method.__name__,
 186                 lc
 187             )
 188         )
 189
 190
 191 class YesNoFilter(admin.SimpleListFilter):
 192     def lookups(self, request, model_admin):
 193         return (
 194             ('yes', _('Yes')),
 195             ('no', _('No')),
 196         )
 197
 198     def queryset(self, request, queryset):
 199         if self.value() == 'yes':
 200             return queryset.filter(self.q)
 201         elif self.value() == 'no':
 202             return queryset.exclude(self.q)
 203
 204
 205 def is_ajax(request):
 206     return request.headers.get('x-requested-with') == 'XMLHttpRequest'