EditingMiddleware (quickly open views and templates in your text editor!)

import os.path
from django.conf import settings
from django.template import Template, Context
from django.test.signals import template_rendered
from django.test.utils import instrumented_test_render
from django.utils.encoding import force_unicode


TEMPLATE = """
<div id="debug" style="background:#85BE40 url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAASCAIAAAAVNSPrAAAAOElEQVQIHWMwSnZi2PGkjunWi5NM/xkYmBj+/2f6/x9IA9n/gGwGIPs/SOwfkGaA0iA+TP4fWD0AipEie4hB/+0AAAAASUVORK5CYII%3D) repeat-x;position:absolute;top:3px;left:3px;padding:5px;-moz-border-radius:5px;text-align:left;">
 <ul>
  <li>
   <a href="{{ view_link }}">{{ view_name }}</a>
   <a style="position:absolute;right:7px;" onclick="document.getElementById('debug').style.display='none';">x</a><br />
  </li>
  {% for t in templates %}
    <li {% if forloop.first %}style="border-top:1px solid white;margin-top:3px;padding-top:3px;"{% endif %}>
     <a href="{{ t.0 }}">{{ t.1 }}</a>
    </li>
  {% endfor %}
 </ul>
<div>
</body>
"""


# Monkeypatch instrumented test renderer from django.test.utils - we could use
# django.test.utils.setup_test_environment for this but that would also set up
# e-mail interception, which we don't want
if Template.render != instrumented_test_render:
    Template.original_render = Template.render
    Template.render = instrumented_test_render
# MONSTER monkey-patch
old_template_init = Template.__init__
def new_template_init(self, template_string, origin=None, name='<Unknown Template>'):
    old_template_init(self, template_string, origin, name)
    self.origin = origin
Template.__init__ = new_template_init


class EditingMiddleware(object):
    link_format = "edit://%s?%s"

    def process_request(self, request):
        self.templates = []
        template_rendered.connect(self.store_template)

    def process_view(self, request, view_func, view_args, view_kwargs):
        self.view_func = view_func
        self.view_args = view_args
        self.view_kwargs = view_kwargs

    def process_response(self, request, response):
        if not self.should_process_response(request, response):
            return response

        view_func = getattr(self, "view_func", None)
        if view_func is None:     
            return response
        
        debug_content = self.get_template().render(self.get_context())
        content = response.content
        response.content = force_unicode(content).replace('</body>', debug_content)
        return response
        
    def get_template(self):
        return Template(TEMPLATE)

    def should_process_response(self, request, response):
        return 'text/html' in response['Content-Type']

    def store_template(self, **kwargs):
        template = kwargs.get("template")
        if template is not None:
            self.templates.append(template)
        
    def get_context(self):
        templates = [
            (self.build_link(os.path.join(settings.TEMPLATE_DIRS[0], t.name)), t.name)
            for t in self.templates
        ]
        
        view_link = self.build_link(self.view_func.func_code.co_filename, 
            self.view_func.func_code.co_firstlineno)
        view_name = "%s.%s" % (self.view_func.__module__, self.view_func.func_name)
        
        return Context({
            "view_link": view_link,
            "view_name": view_name,
            "templates": templates})
    
    def build_link(self, filename, lineno=0):
        return self.link_format % (filename, lineno)
    
        

class TextMateEditingMiddleware(EditingMiddleware):
    link_format = "txmt://open/?url=file://%s&line=%s"