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     action = ''
  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() and not request.is_ajax():
 123                 return require_login(request)
 124
 125             form = self.form_class(*form_args, **form_kwargs)
 126             response_data = None
 127
 128         title = self.title
 129         if request.is_ajax():
 130             template = self.template
 131         else:
 132             template = self.full_template
 133             cd = self.context_description(request, obj)
 134             if cd:
 135                 title += ": " + cd
 136         if self.placeholdize:
 137             form = placeholdized(form)
 138         context = {
 139                 self.formname: form,
 140                 "title": title,
 141                 "honeypot": self.honeypot,
 142                 "placeholdize": self.placeholdize,
 143                 "submit": self.submit,
 144                 "action": self.action,
 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, context_instance=RequestContext(request))
 152
 153     def redirect_or_refresh(self, request, path, message=None):
 154         """If the form is AJAX, refresh the page. If not, go to `path`."""
 155         if request.is_ajax():
 156             output = "<script>window.location.reload()</script>"
 157             if message:
 158                 output = "<div class='normal-text'>" + message + "</div>" + output
 159             return HttpResponse(output)
 160         else:
 161             return HttpResponseRedirect(path)
 162
 163     def get_object(self, request, *args, **kwargs):
 164         """Override to parse view args and get some associated data."""
 165         return None
 166
 167     def form_args(self, request, obj):
 168         """Override to parse view args and give additional args to the form."""
 169         return (), {}
 170
 171     def extra_context(self, request, obj):
 172         """Override to pass something to template."""
 173         return {}
 174
 175     def context_description(self, request, obj):
 176         """Description to appear in standalone form, but not in AJAX form."""
 177         return ""
 178
 179     def success(self, form, request):
 180         """What to do when the form is valid.
 181
 182         By default, just save the form.
 183
 184         """
 185         return form.save(request)