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
  81         response = self.validate_object(obj, request)
  82         if response:
  83             return response
  84
  85         form_args, form_kwargs = self.form_args(request, obj)
  86         if self.form_prefix:
  87             form_kwargs['prefix'] = self.form_prefix
  88
  89         if request.method == "POST":
  90             if self.honeypot:
  91                 response = verify_honeypot_value(request, None)
  92                 if response:
  93                     return response
  94
  95             # do I need to be logged in?
  96             if self.POST_login and not request.user.is_authenticated():
  97                 return require_login(request)
  98
  99             form_kwargs['data'] = request.POST
 100             form = self.form_class(*form_args, **form_kwargs)
 101             if form.is_valid():
 102                 add_args = self.success(form, request)
 103                 response_data = {
 104                     'success': True,
 105                     'message': self.success_message,
 106                     'redirect': request.GET.get('next')
 107                     }
 108                 if add_args:
 109                     response_data.update(add_args)
 110                 if not request.is_ajax() and response_data['redirect']:
 111                     return HttpResponseRedirect(urlquote_plus(
 112                             response_data['redirect'], safe='/?=&'))
 113             elif request.is_ajax():
 114                 # Form was sent with errors. Send them back.
 115                 if self.form_prefix:
 116                     errors = {}
 117                     for key, value in form.errors.items():
 118                         errors["%s-%s" % (self.form_prefix, key)] = value
 119                 else:
 120                     errors = form.errors
 121                 response_data = {'success': False, 'errors': errors}
 122             else:
 123                 response_data = None
 124             if request.is_ajax():
 125                 return HttpResponse(LazyEncoder(ensure_ascii=False).encode(response_data))
 126         else:
 127             if self.POST_login and not request.user.is_authenticated() and not request.is_ajax():
 128                 return require_login(request)
 129
 130             form = self.form_class(*form_args, **form_kwargs)
 131             response_data = None
 132
 133         title = self.title
 134         if request.is_ajax():
 135             template = self.template
 136         else:
 137             template = self.full_template
 138             cd = self.context_description(request, obj)
 139             if cd:
 140                 title += ": " + cd
 141         if self.placeholdize:
 142             form = placeholdized(form)
 143         context = {
 144                 self.formname: form,
 145                 "title": title,
 146                 "honeypot": self.honeypot,
 147                 "placeholdize": self.placeholdize,
 148                 "submit": self.submit,
 149                 "action": self.action,
 150                 "response_data": response_data,
 151                 "ajax_template": self.template,
 152                 "view_args": args,
 153                 "view_kwargs": kwargs,
 154             }
 155         context.update(self.extra_context(request, obj))
 156         return render_to_response(template, context, context_instance=RequestContext(request))
 157
 158     def validate_object(self, obj, request):
 159         return None
 160
 161     def redirect_or_refresh(self, request, path, message=None):
 162         """If the form is AJAX, refresh the page. If not, go to `path`."""
 163         if request.is_ajax():
 164             output = "<script>window.location.reload()</script>"
 165             if message:
 166                 output = "<div class='normal-text'>" + message + "</div>" + output
 167             return HttpResponse(output)
 168         else:
 169             return HttpResponseRedirect(path)
 170
 171     def get_object(self, request, *args, **kwargs):
 172         """Override to parse view args and get some associated data."""
 173         return None
 174
 175     def form_args(self, request, obj):
 176         """Override to parse view args and give additional args to the form."""
 177         return (), {}
 178
 179     def extra_context(self, request, obj):
 180         """Override to pass something to template."""
 181         return {}
 182
 183     def context_description(self, request, obj):
 184         """Description to appear in standalone form, but not in AJAX form."""
 185         return ""
 186
 187     def success(self, form, request):
 188         """What to do when the form is valid.
 189
 190         By default, just save the form.
 191
 192         """
 193         return form.save(request)