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