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