src/ajaxable/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 from functools import wraps
   5
   6 from django.http import HttpResponse, HttpResponseRedirect, HttpResponseForbidden
   7 from django.shortcuts import render
   8 from django.utils.encoding import force_text
   9 from django.utils.functional import Promise
  10 from django.utils.http import urlquote_plus
  11 import json
  12 from django.utils.translation import ugettext_lazy as _
  13 from django.views.decorators.vary import vary_on_headers
  14 from honeypot.decorators import verify_honeypot_value
  15
  16
  17 class LazyEncoder(json.JSONEncoder):
  18     def default(self, obj):
  19         if isinstance(obj, Promise):
  20             return force_text(obj)
  21         return obj
  22
  23
  24 def method_decorator(function_decorator):
  25     """Converts a function decorator to a method decorator.
  26
  27     It just makes it ignore first argument.
  28     """
  29     def decorator(method):
  30         @wraps(method)
  31         def wrapped_method(self, *args, **kwargs):
  32             def function(*fargs, **fkwargs):
  33                 return method(self, *fargs, **fkwargs)
  34             return function_decorator(function)(*args, **kwargs)
  35         return wrapped_method
  36     return decorator
  37
  38
  39 def require_login(request):
  40     """Return 403 if request is AJAX. Redirect to login page if not."""
  41     if request.is_ajax():
  42         return HttpResponseForbidden('Not logged in')
  43     else:
  44         return HttpResponseRedirect('/uzytkownicy/zaloguj')  # next?=request.build_full_path())
  45
  46
  47 def placeholdized(form):
  48     for field in form.fields.values():
  49         field.widget.attrs['placeholder'] = field.label + ('*' if field.required else '')
  50     return form
  51
  52
  53 class AjaxableFormView(object):
  54     """Subclass this to create an ajaxable view for any form.
  55
  56     In the subclass, provide at least form_class.
  57
  58     """
  59     form_class = None
  60     placeholdize = False
  61     # override to customize form look
  62     template = "ajaxable/form.html"
  63     submit = _('Send')
  64     action = ''
  65
  66     title = ''
  67     success_message = ''
  68     POST_login = False
  69     formname = "form"
  70     form_prefix = None
  71     full_template = "ajaxable/form_on_page.html"
  72     honeypot = False
  73
  74     @method_decorator(vary_on_headers('X-Requested-With'))
  75     def __call__(self, request, *args, **kwargs):
  76         """A view displaying a form, or JSON if request is AJAX."""
  77         obj = self.get_object(request, *args, **kwargs)
  78
  79         response = self.validate_object(obj, request)
  80         if response:
  81             return response
  82
  83         form_args, form_kwargs = self.form_args(request, obj)
  84         if self.form_prefix:
  85             form_kwargs['prefix'] = self.form_prefix
  86
  87         if request.method == "POST":
  88             if self.honeypot:
  89                 response = verify_honeypot_value(request, None)
  90                 if response:
  91                     return response
  92
  93             # do I need to be logged in?
  94             if self.POST_login and not request.user.is_authenticated:
  95                 return require_login(request)
  96
  97             form_kwargs['data'] = request.POST
  98             form = self.form_class(*form_args, **form_kwargs)
  99             if form.is_valid():
 100                 add_args = self.success(form, request)
 101                 response_data = {
 102                     'success': True,
 103                     'message': self.success_message,
 104                     'redirect': request.GET.get('next')
 105                     }
 106                 if add_args:
 107                     response_data.update(add_args)
 108                 if not request.is_ajax() and response_data['redirect']:
 109                     return HttpResponseRedirect(urlquote_plus(
 110                             response_data['redirect'], safe='/?=&'))
 111             elif request.is_ajax():
 112                 # Form was sent with errors. Send them back.
 113                 if self.form_prefix:
 114                     errors = {}
 115                     for key, value in form.errors.items():
 116                         errors["%s-%s" % (self.form_prefix, key)] = value
 117                 else:
 118                     errors = form.errors
 119                 response_data = {'success': False, 'errors': errors}
 120             else:
 121                 response_data = None
 122             if request.is_ajax():
 123                 return HttpResponse(LazyEncoder(ensure_ascii=False).encode(response_data))
 124         else:
 125             if self.POST_login and not request.user.is_authenticated and not request.is_ajax():
 126                 return require_login(request)
 127
 128             form = self.form_class(*form_args, **form_kwargs)
 129             response_data = None
 130
 131         title = self.title
 132         if request.is_ajax():
 133             template = self.template
 134         else:
 135             template = self.full_template
 136             cd = self.context_description(request, obj)
 137             if cd:
 138                 title += ": " + cd
 139         if self.placeholdize:
 140             form = placeholdized(form)
 141         context = {
 142                 self.formname: form,
 143                 "title": title,
 144                 "honeypot": self.honeypot,
 145                 "placeholdize": self.placeholdize,
 146                 "submit": self.submit,
 147                 "action": self.action,
 148                 "response_data": response_data,
 149                 "ajax_template": self.template,
 150                 "view_args": args,
 151                 "view_kwargs": kwargs,
 152             }
 153         context.update(self.extra_context(request, obj))
 154         return render(request, template, context)
 155
 156     def validate_object(self, obj, request):
 157         return None
 158
 159     def redirect_or_refresh(self, request, path, message=None):
 160         """If the form is AJAX, refresh the page. If not, go to `path`."""
 161         if request.is_ajax():
 162             output = "<script>window.location.reload()</script>"
 163             if message:
 164                 output = "<div class='normal-text'>" + message + "</div>" + output
 165             return HttpResponse(output)
 166         else:
 167             return HttpResponseRedirect(path)
 168
 169     def get_object(self, request, *args, **kwargs):
 170         """Override to parse view args and get some associated data."""
 171         return None
 172
 173     def form_args(self, request, obj):
 174         """Override to parse view args and give additional args to the form."""
 175         return (), {}
 176
 177     def extra_context(self, request, obj):
 178         """Override to pass something to template."""
 179         return {}
 180
 181     def context_description(self, request, obj):
 182         """Description to appear in standalone form, but not in AJAX form."""
 183         return ""
 184
 185     def success(self, form, request):
 186         """What to do when the form is valid.
 187
 188         By default, just save the form.
 189
 190         """
 191         return form.save(request)