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 import re
  16 from django.core.mail import send_mail
  17 from django.http import HttpResponse
  18 from django.template import RequestContext
  19 from django.template.loader import render_to_string
  20 from django.utils import timezone
  21 from django.conf import settings
  22 from django.utils.translation import ugettext
  23
  24 tz = pytz.timezone(settings.TIME_ZONE)
  25
  26
  27 def localtime_to_utc(localtime):
  28     return timezone.utc.normalize(
  29         tz.localize(localtime)
  30     )
  31
  32
  33 def utc_for_js(dt):
  34     return dt.strftime('%Y/%m/%d %H:%M:%S UTC')
  35
  36
  37 def makedirs(path):
  38     if not os.path.isdir(path):
  39         os.makedirs(path)
  40
  41
  42 def stringify_keys(dictionary):
  43     return dict((keyword.encode('ascii'), value)
  44                 for keyword, value in dictionary.iteritems())
  45
  46
  47 def json_encode(obj, sort_keys=True, ensure_ascii=False):
  48     return json.dumps(obj, sort_keys=sort_keys, ensure_ascii=ensure_ascii)
  49
  50
  51 def json_decode(obj):
  52     return json.loads(obj)
  53
  54
  55 def json_decode_fallback(value):
  56     try:
  57         return json_decode(value)
  58     except ValueError:
  59         return value
  60
  61
  62 class AjaxError(Exception):
  63     pass
  64
  65
  66 def ajax(login_required=False, method=None, template=None, permission_required=None):
  67     def decorator(fun):
  68         @wraps(fun)
  69         def ajax_view(request):
  70             kwargs = {}
  71             request_params = None
  72             if method == 'post':
  73                 request_params = request.POST
  74             elif method == 'get':
  75                 request_params = request.GET
  76             fun_params, xx, fun_kwargs, defaults = getargspec(fun)
  77             if defaults:
  78                 required_params = fun_params[1:-len(defaults)]
  79             else:
  80                 required_params = fun_params[1:]
  81             missing_params = set(required_params) - set(request_params)
  82             if missing_params:
  83                 res = {
  84                     'result': 'missing params',
  85                     'missing': ', '.join(missing_params),
  86                 }
  87             else:
  88                 if request_params:
  89                     request_params = dict(
  90                         (key, json_decode_fallback(value))
  91                         for key, value in request_params.iteritems()
  92                         if fun_kwargs or key in fun_params)
  93                     kwargs.update(stringify_keys(request_params))
  94                 res = None
  95                 if login_required and not request.user.is_authenticated():
  96                     res = {'result': 'logout'}
  97                 if (permission_required and
  98                         not request.user.has_perm(permission_required)):
  99                     res = {'result': 'access denied'}
 100             if not res:
 101                 try:
 102                     res = fun(request, **kwargs)
 103                     if res and template:
 104                         res = {'html': render_to_string(template, res, RequestContext(request))}
 105                 except AjaxError as e:
 106                     res = {'result': e.args[0]}
 107             if 'result' not in res:
 108                 res['result'] = 'ok'
 109             return HttpResponse(json_encode(res), content_type='application/json; charset=utf-8',
 110                                 status=200 if res['result'] == 'ok' else 400)
 111
 112         return ajax_view
 113
 114     return decorator
 115
 116
 117 def send_noreply_mail(subject, message, recipient_list, **kwargs):
 118     send_mail(
 119         u'[WolneLektury] ' + subject,
 120         message + u"\n\n-- \n" + ugettext(u'Message sent automatically. Please do not reply.'),
 121         'no-reply@wolnelektury.pl', recipient_list, **kwargs)
 122
 123
 124 # source: https://docs.python.org/2/library/csv.html#examples
 125 class UnicodeCSVWriter(object):
 126     """
 127     A CSV writer which will write rows to CSV file "f",
 128     which is encoded in the given encoding.
 129     """
 130
 131     def __init__(self, f, dialect=csv.excel, encoding="utf-8", **kwds):
 132         # Redirect output to a queue
 133         self.queue = cStringIO.StringIO()
 134         self.writer = csv.writer(self.queue, dialect=dialect, **kwds)
 135         self.stream = f
 136         self.encoder = codecs.getincrementalencoder(encoding)()
 137
 138     def writerow(self, row):
 139         self.writer.writerow([s.encode("utf-8") for s in row])
 140         # Fetch UTF-8 output from the queue ...
 141         data = self.queue.getvalue()
 142         data = data.decode("utf-8")
 143         # ... and reencode it into the target encoding
 144         data = self.encoder.encode(data)
 145         # write to the target stream
 146         self.stream.write(data)
 147         # empty queue
 148         self.queue.truncate(0)
 149
 150     def writerows(self, rows):
 151         for row in rows:
 152             self.writerow(row)
 153
 154
 155 # the original re.escape messes with unicode
 156 def re_escape(s):
 157     return re.sub(r"[(){}\[\].*?|^$\\+-]", r"\\\g<0>", s)