apps/ajaxable/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 from functools import wraps
   6
   7 from django.http import (HttpResponse, HttpResponseRedirect,
   8         HttpResponseForbidden)
   9 from django.shortcuts import render_to_response
  10 from django.template import RequestContext
  11 from django.utils.encoding import force_unicode
  12 from django.utils.functional import Promise
  13 from django.utils.http import urlquote_plus
  14 import json
  15 from django.utils.translation import ugettext_lazy as _
  16 from django.views.decorators.vary import vary_on_headers
  17 from honeypot.decorators import verify_honeypot_value
  18
  19
  20 class LazyEncoder(json.JSONEncoder):
  21     def default(self, obj):
  22         if isinstance(obj, Promise):
  23             return force_unicode(obj)
  24         return obj
  25
  26
  27 def method_decorator(function_decorator):
  28     """Converts a function decorator to a method decorator.
  29
  30     It just makes it ignore first argument.
  31     """
  32     def decorator(method):
  33         @wraps(method)
  34         def wrapped_method(self, *args, **kwargs):
  35             def function(*fargs, **fkwargs):
  36                 return method(self, *fargs, **fkwargs)
  37             return function_decorator(function)(*args, **kwargs)
  38         return wrapped_method
  39     return decorator
  40
  41
  42 def require_login(request):
  43     """Return 403 if request is AJAX. Redirect to login page if not."""
  44     if request.is_ajax():
  45         return HttpResponseForbidden('Not logged in')
  46     else:
  47         return HttpResponseRedirect('/uzytkownicy/zaloguj')# next?=request.build_full_path())
  48
  49
  50 def placeholdized(form):
  51     for field in form.fields.values():
  52         field.widget.attrs['placeholder'] = field.label
  53     return form
  54
  55
  56 class AjaxableFormView(object):
  57     """Subclass this to create an ajaxable view for any form.
  58
  59     In the subclass, provide at least form_class.
  60
  61     """
  62     form_class = None
  63     placeholdize = False
  64     # override to customize form look
  65     template = "ajaxable/form.html"
  66     submit = _('Send')
  67
  68     title = ''
  69     success_message = ''
  70     POST_login = False
  71     formname = "form"
  72     form_prefix = None
  73     full_template = "ajaxable/form_on_page.html"
  74     honeypot = False
  75
  76     @method_decorator(vary_on_headers('X-Requested-With'))
  77     def __call__(self, request, *args, **kwargs):
  78         """A view displaying a form, or JSON if request is AJAX."""
  79         obj = self.get_object(request, *args, **kwargs)
  80         form_args, form_kwargs = self.form_args(request, obj)
  81         if self.form_prefix:
  82             form_kwargs['prefix'] = self.form_prefix
  83
  84         if request.method == "POST":
  85             if self.honeypot:
  86                 response = verify_honeypot_value(request, None)
  87                 if response:
  88                     return response
  89
  90             # do I need to be logged in?
  91             if self.POST_login and not request.user.is_authenticated():
  92                 return require_login(request)
  93
  94             form_kwargs['data'] = request.POST
  95             form = self.form_class(*form_args, **form_kwargs)
  96             if form.is_valid():
  97                 add_args = self.success(form, request)
  98                 response_data = {
  99                     'success': True,
 100                     'message': self.success_message,
 101                     'redirect': request.GET.get('next')
 102                     }
 103                 if add_args:
 104                     response_data.update(add_args)
 105                 if not request.is_ajax() and response_data['redirect']:
 106                     return HttpResponseRedirect(urlquote_plus(
 107                             response_data['redirect'], safe='/?=&'))
 108             elif request.is_ajax():
 109                 # Form was sent with errors. Send them back.
 110                 if self.form_prefix:
 111                     errors = {}
 112                     for key, value in form.errors.items():
 113                         errors["%s-%s" % (self.form_prefix, key)] = value
 114                 else:
 115                     errors = form.errors
 116                 response_data = {'success': False, 'errors': errors}
 117             else:
 118                 response_data = None
 119             if request.is_ajax():
 120                 return HttpResponse(LazyEncoder(ensure_ascii=False).encode(response_data))
 121         else:
 122             if (self.POST_login and not request.user.is_authenticated()
 123                     and not request.is_ajax()):
 124                 return require_login(request)
 125
 126             form = self.form_class(*form_args, **form_kwargs)
 127             response_data = None
 128
 129         title = self.title
 130         if request.is_ajax():
 131             template = self.template
 132         else:
 133             template = self.full_template
 134             cd = self.context_description(request, obj)
 135             if cd:
 136                 title += ": " + cd
 137         if self.placeholdize:
 138             form = placeholdized(form)
 139         context = {
 140                 self.formname: form,
 141                 "title": title,
 142                 "honeypot": self.honeypot,
 143                 "placeholdize": self.placeholdize,
 144                 "submit": self.submit,
 145                 "response_data": response_data,
 146                 "ajax_template": self.template,
 147                 "view_args": args,
 148                 "view_kwargs": kwargs,
 149             }
 150         context.update(self.extra_context(request, obj))
 151         return render_to_response(template, context,
 152             context_instance=RequestContext(request))
 153
 154     def redirect_or_refresh(self, request, path, message=None):
 155         """If the form is AJAX, refresh the page. If not, go to `path`."""
 156         if request.is_ajax():
 157             output = "<script>window.location.reload()</script>"
 158             if message:
 159                 output = "<div class='normal-text'>" + message + "</div>" + output
 160             return HttpResponse(output)
 161         else:
 162             return HttpResponseRedirect(path)
 163
 164     def get_object(self, request, *args, **kwargs):
 165         """Override to parse view args and get some associated data."""
 166         return None
 167
 168     def form_args(self, request, obj):
 169         """Override to parse view args and give additional args to the form."""
 170         return (), {}
 171
 172     def extra_context(self, request, obj):
 173         """Override to pass something to template."""
 174         return {}
 175
 176     def context_description(self, request, obj):
 177         """Description to appear in standalone form, but not in AJAX form."""
 178         return ""
 179
 180     def success(self, form, request):
 181         """What to do when the form is valid.
 182
 183         By default, just save the form.
 184
 185         """
 186         return form.save(request)