src/wolnelektury/utils.py

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