Writing a custom tag which needs access to the request object_问答_开发者

I'm writing my own custom template tag for Django for a purpose I keep coming across. I need to conditionally insert a form input if the URL is right. Essentially, I need to encapsulate the following template markup into a custom tag definition:

{% if request.path != "/login/" and request.path != "/logout/" %}
<div style="display:none;"><input type="hidden" name="redirect_url" value="{{request.path}}" /></div>
{% endif %}

I've tried doing this by making a custom template tag like so:

from django import template
import re

register = template.Library()

class RedirectUrlNode(template.Node):
    def render(self, context):
        current_path = context.request.path
        if re.match("^log(?:in|out)/?", current_path):
            return ""
        else:
            return "..." # insert div and input elements here

def do_redirect_url(parser, token):
    return RedirectUrlNode()

register.tag("redirect_url", do_redirect_url)

I'm getting the following error:

Environment:


Request Method: GET
Request URL: http://localhost:8000/

Django Version: 1.3
Python Version: 2.7.1
Installed Applications:
['django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.sites',
 'django.contrib.messages',
 'django.contrib.admin',
 'django.contrib.admindocs',
 'django.contrib.staticfiles',
 'myproject.web',
 'reversion',
 'south']
Installed Middleware:
('django.middleware.common.CommonMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware')


Template error:
In template /home/rfkrocktk/Desktop/myproject/src/myproject/web/templates/desktop/foundation.html, error at line 24
   Caught AttributeError while rendering: 'RequestContext' object has no attribute 'request'
   14 :                             <li class="dropdown" data-dropdown="dropdown">


   15 :                                 <a class="dropdown-toggle">{{user.first_name}}</a>


   16 :                                 <ul class="dropdown-menu">


   17 :                                     <li>


   18 :                                         <a href="/me/">Preferences</a>


   19 :                                     </li>


   20 :                                     <li class="divider"></li>


   21 :                                     <li>


   22 :                                         <form id="logoutForm" method="post" action="/logout/">


   23 :                                             {% csrf_token %}


   24 :                                              {% redirect_url %} 


   25 :                                             <a href="#" onclick="document.logoutForm.submit()">Log Out</a>


   26 :                                         </form>


   27 :                                     </li>


   28 :                                 </ul>


   29 :                             </li>


   30 :                         </ul>


   31 :                     {% else %}


   32 :                         <form id="loginForm" style="float:right;" action="/login/" method="post">


   33 :                             {% csrf_token %}


   34 :                             {% if request.path != "/login/" and request.path != "/logout/" %}<div style="display:none;"><input type="hidden" name="redirect_url" value="{{request.path}}" /></div>{% endif %}


Traceback:
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/core/handlers/base.py" in get_response
  111.                         response = callback(request, *callback_args, **callback_kwargs)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/views/generic/simple.py" in direct_to_template
  28.     return HttpResponse(t.render(c), mimetype=mimetype)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/base.py" in render
  123.             return self._render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/base.py" in _render
  117.         return self.nodelist.render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/base.py" in render
  744.                 bits.append(self.render_node(node, context))
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/debug.py" in render_node
  73.             result = node.render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/loader_tags.py" in render
  127.         return compiled_parent._render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/base.py" in _render
  117.         return self.nodelist.render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/base.py" in render
  744.                 bits.append(self.render_node(node, context))
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/debug.py" in render_node
  73.             result = node.render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/loader_tags.py" in render
  127.         return compiled_parent._render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/base.py" in _render
  117.         return self.nodelist.render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/base.py" in render
  744.                 bits.append(self.render_node(node, context))
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/debug.py" in render_node
  73.             result = node.render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/loader_tags.py" in render
  64.             result = block.nodelist.render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/base.py" in render
  744.                 bits.append(self.render_node(node, context))
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/debug.py" in render_node
  73.          开发者_JAVA百科   result = node.render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/loader_tags.py" in render
  64.             result = block.nodelist.render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/base.py" in render
  744.                 bits.append(self.render_node(node, context))
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/debug.py" in render_node
  73.             result = node.render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/defaulttags.py" in render
  311.             return self.nodelist_true.render(context)
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/base.py" in render
  744.                 bits.append(self.render_node(node, context))
File "/home/rfkrocktk/Desktop/myproject/eggs/Django-1.3-py2.7.egg/django/template/debug.py" in render_node
  73.             result = node.render(context)
File "/home/rfkrocktk/Desktop/myproject/src/myproject/web/templatetags/form_shortcuts.py" in render
  8.        current_path = context.request.path

Exception Type: TemplateSyntaxError at /
Exception Value: Caught AttributeError while rendering: 'RequestContext' object has no attribute 'request'

The context is a mapping, and you should index it.