apps/ajaxable/utils.py

   1 from functools import wraps
   2
   3 from django.http import (HttpResponse, HttpResponseRedirect,
   4         HttpResponseForbidden)
   5 from django.shortcuts import render_to_response
   6 from django.template import RequestContext
   7 from django.utils.cache import patch_vary_headers
   8 from django.utils.encoding import force_unicode
   9 from django.utils.functional import Promise
  10 from django.utils.http import urlquote_plus
  11 from django.utils import simplejson
  12 from django.utils.translation import ugettext_lazy as _
  13 from django.views.decorators.vary import vary_on_headers
  14
  15
  16 class LazyEncoder(simplejson.JSONEncoder):
  17     def default(self, obj):
  18         if isinstance(obj, Promise):
  19             return force_unicode(obj)
  20         return obj
  21
  22 # shortcut for JSON reponses
  23 class JSONResponse(HttpResponse):
  24     def __init__(self, data={}, callback=None, **kwargs):
  25         # get rid of mimetype
  26         kwargs.pop('mimetype', None)
  27         data = simplejson.dumps(data)
  28         if callback:
  29             data = callback + "(" + data + ");"
  30         super(JSONResponse, self).__init__(data, mimetype="application/json", **kwargs)
  31
  32
  33 def method_decorator(function_decorator):
  34     """Converts a function decorator to a method decorator.
  35
  36     It just makes it ignore first argument.
  37     """
  38     def decorator(method):
  39         @wraps(method)
  40         def wrapped_method(self, *args, **kwargs):
  41             def function(*fargs, **fkwargs):
  42                 return method(self, *fargs, **fkwargs)
  43             return function_decorator(function)(*args, **kwargs)
  44         return wrapped_method
  45     return decorator
  46
  47
  48 def require_login(request):
  49     """Return 403 if request is AJAX. Redirect to login page if not."""
  50     if request.is_ajax():
  51         return HttpResponseForbidden('Not logged in')
  52     else:
  53         return HttpResponseRedirect('/uzytkownicy/zaloguj')# next?=request.build_full_path())
  54
  55
  56 def placeholdized(form):
  57     for field in form.fields.values():
  58         field.widget.attrs['placeholder'] = field.label
  59     return form
  60
  61
  62 class AjaxableFormView(object):
  63     """Subclass this to create an ajaxable view for any form.
  64
  65     In the subclass, provide at least form_class.
  66
  67     """
  68     form_class = None
  69     placeholdize = False
  70     # override to customize form look
  71     template = "ajaxable/form.html"
  72     submit = _('Send')
  73
  74     title = ''
  75     success_message = ''
  76     POST_login = False
  77     formname = "form"
  78     form_prefix = None
  79     full_template = "ajaxable/form_on_page.html"
  80
  81     @method_decorator(vary_on_headers('X-Requested-With'))
  82     def __call__(self, request, *args, **kwargs):
  83         """A view displaying a form, or JSON if request is AJAX."""
  84         obj = self.get_object(request, *args, **kwargs)
  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             # 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                 redirect = request.GET.get('next')
  99                 if not request.is_ajax() and redirect:
 100                     return HttpResponseRedirect(urlquote_plus(
 101                             redirect, safe='/?=&'))
 102                 response_data = {'success': True,
 103                     'message': self.success_message, 'redirect': redirect}
 104                 if add_args:
 105                     response_data.update(add_args)
 106             elif request.is_ajax():
 107                 # Form was sent with errors. Send them back.
 108                 if self.form_prefix:
 109                     errors = {}
 110                     for key, value in form.errors.items():
 111                         errors["%s-%s" % (self.form_prefix, key)] = value
 112                 else:
 113                     errors = form.errors
 114                 response_data = {'success': False, 'errors': errors}
 115             else:
 116                 response_data = None
 117             if request.is_ajax():
 118                 return HttpResponse(LazyEncoder(ensure_ascii=False).encode(response_data))
 119         else:
 120             if (self.POST_login and not request.user.is_authenticated()
 121                     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                 "placeholdize": self.placeholdize,
 141                 "submit": self.submit,
 142                 "response_data": response_data,
 143                 "ajax_template": self.template,
 144                 "view_args": args,
 145                 "view_kwargs": kwargs,
 146             }
 147         context.update(self.extra_context(request, obj))
 148         return render_to_response(template, context,
 149             context_instance=RequestContext(request))
 150
 151     def get_object(self, request, *args, **kwargs):
 152         """Override to parse view args and get some associated data."""
 153         return None
 154
 155     def form_args(self, request, obj):
 156         """Override to parse view args and give additional args to the form."""
 157         return (), {}
 158
 159     def extra_context(self, request, obj):
 160         """Override to pass something to template."""
 161         return {}
 162
 163     def context_description(self, request, obj):
 164         """Description to appear in standalone form, but not in AJAX form."""
 165         return ""
 166
 167     def success(self, form, request):
 168         """What to do when the form is valid.
 169
 170         By default, just save the form.
 171
 172         """
 173         return form.save(request)