Query fragments also by book id.
[wolnelektury.git] / 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)