Django的TemplateResponse

def my_render_callback(response):
return response

from django.template.response import TemplateResponse
def my_templateresponse(request):
response =  TemplateResponse(request, 'template.html', {})
response.add_post_render_callback(my_render_callback);
return response

we call add_post_render_callback to register a callback function.

in base.py , get_response

if hasattr(response, 'render') and callable(response.render):
for middleware_method in self._template_response_middleware:
response = middleware_method(request, response)
response = response.render()

The response is a TemplateResponse, the subclass of SimpleTemplateResponse

it has a 'render' function

def render(self):
"""Renders (thereby finalizing) the content of the response.

If the content has already been rendered, this is a no-op.

Returns the baked response instance.
"""
retval = self
if not self._is_rendered:
self.content = self.rendered_content
for post_callback in self._post_render_callbacks:
newretval = post_callback(retval)
if newretval is not None:
retval = newretval
return retval

需要注意的是这个callback的返回值, 如果 not None, 它的返回值就是我们最后的response,