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 codecs
   6 import csv
   7 import cStringIO
   8 import json
   9 import os
  10 from functools import wraps
  11
  12 import pytz
  13 from inspect import getargspec
  14
  15 from django.core.mail import send_mail
  16 from django.http import HttpResponse
  17 from django.template import RequestContext
  18 from django.template.loader import render_to_string
  19 from django.utils import timezone
  20 from django.conf import settings
  21 from django.utils.translation import ugettext
  22
  23 tz = pytz.timezone(settings.TIME_ZONE)
  24
  25
  26 def localtime_to_utc(localtime):
  27     return timezone.utc.normalize(
  28         tz.localize(localtime)
  29     )
  30
  31
  32 def utc_for_js(dt):
  33     return dt.strftime('%Y/%m/%d %H:%M:%S UTC')
  34
  35
  36 def makedirs(path):
  37     if not os.path.isdir(path):
  38         os.makedirs(path)
  39
  40
  41 def stringify_keys(dictionary):
  42     return dict((keyword.encode('ascii'), value)
  43                 for keyword, value in dictionary.iteritems())
  44
  45
  46 def json_encode(obj, sort_keys=True, ensure_ascii=False):
  47     return json.dumps(obj, sort_keys=sort_keys, ensure_ascii=ensure_ascii)
  48
  49
  50 def json_decode(obj):
  51     return json.loads(obj)
  52
  53
  54 def json_decode_fallback(value):
  55     try:
  56         return json_decode(value)
  57     except ValueError:
  58         return value
  59
  60
  61 class AjaxError(Exception):
  62     pass
  63
  64
  65 def ajax(login_required=False, method=None, template=None, permission_required=None):
  66     def decorator(fun):
  67         @wraps(fun)
  68         def ajax_view(request):
  69             kwargs = {}
  70             request_params = None
  71             if method == 'post':
  72                 request_params = request.POST
  73             elif method == 'get':
  74                 request_params = request.GET
  75             fun_params, xx, fun_kwargs, defaults = getargspec(fun)
  76             if defaults:
  77                 required_params = fun_params[1:-len(defaults)]
  78             else:
  79                 required_params = fun_params[1:]
  80             missing_params = set(required_params) - set(request_params)
  81             if missing_params:
  82                 res = {
  83                     'result': 'missing params',
  84                     'missing': ', '.join(missing_params),
  85                 }
  86             else:
  87                 if request_params:
  88                     request_params = dict(
  89                         (key, json_decode_fallback(value))
  90                         for key, value in request_params.iteritems()
  91                         if fun_kwargs or key in fun_params)
  92                     kwargs.update(stringify_keys(request_params))
  93                 res = None
  94                 if login_required and not request.user.is_authenticated():
  95                     res = {'result': 'logout'}
  96                 if (permission_required and
  97                         not request.user.has_perm(permission_required)):
  98                     res = {'result': 'access denied'}
  99             if not res:
 100                 try:
 101                     res = fun(request, **kwargs)
 102                     if res and template:
 103                         res = {'html': render_to_string(template, res, RequestContext(request))}
 104                 except AjaxError as e:
 105                     res = {'result': e.args[0]}
 106             if 'result' not in res:
 107                 res['result'] = 'ok'
 108             return HttpResponse(json_encode(res), content_type='application/json; charset=utf-8',
 109                                 status=200 if res['result'] == 'ok' else 400)
 110
 111         return ajax_view
 112
 113     return decorator
 114
 115
 116 def send_noreply_mail(subject, message, recipient_list, **kwargs):
 117     send_mail(
 118         u'[WolneLektury] ' + subject,
 119         message + u"\n\n-- \n" + ugettext(u'Message sent automatically. Please do not reply.'),
 120         'no-reply@wolnelektury.pl', recipient_list, **kwargs)
 121
 122
 123 # source: https://docs.python.org/2/library/csv.html#examples
 124 class UnicodeCSVWriter(object):
 125     """
 126     A CSV writer which will write rows to CSV file "f",
 127     which is encoded in the given encoding.
 128     """
 129
 130     def __init__(self, f, dialect=csv.excel, encoding="utf-8", **kwds):
 131         # Redirect output to a queue
 132         self.queue = cStringIO.StringIO()
 133         self.writer = csv.writer(self.queue, dialect=dialect, **kwds)
 134         self.stream = f
 135         self.encoder = codecs.getincrementalencoder(encoding)()
 136
 137     def writerow(self, row):
 138         self.writer.writerow([s.encode("utf-8") for s in row])
 139         # Fetch UTF-8 output from the queue ...
 140         data = self.queue.getvalue()
 141         data = data.decode("utf-8")
 142         # ... and reencode it into the target encoding
 143         data = self.encoder.encode(data)
 144         # write to the target stream
 145         self.stream.write(data)
 146         # empty queue
 147         self.queue.truncate(0)
 148
 149     def writerows(self, rows):
 150         for row in rows:
 151             self.writerow(row)