from django.http import HttpResponse
from django.utils import six
from .loader import get_template, select_template
class ContentNotRenderedError(Exception):
pass
[docs]class SimpleTemplateResponse(HttpResponse):
rendering_attrs = ['template_name', 'context_data', '_post_render_callbacks']
[docs] def __init__(self, template, context=None, content_type=None, status=None,
charset=None, using=None):
# It would seem obvious to call these next two members 'template' and
# 'context', but those names are reserved as part of the test Client
# API. To avoid the name collision, we use different names.
self.template_name = template
self.context_data = context
self.using = using
self._post_render_callbacks = []
# _request stores the current request object in subclasses that know
# about requests, like TemplateResponse. It's defined in the base class
# to minimize code duplication.
# It's called self._request because self.request gets overwritten by
# django.test.client.Client. Unlike template_name and context_data,
# _request should not be considered part of the public API.
self._request = None
# content argument doesn't make sense here because it will be replaced
# with rendered template so we always pass empty string in order to
# prevent errors and provide shorter signature.
super(SimpleTemplateResponse, self).__init__('', content_type, status, charset=charset)
# _is_rendered tracks whether the template and context has been baked
# into a final response.
# Super __init__ doesn't know any better than to set self.content to
# the empty string we just gave it, which wrongly sets _is_rendered
# True, so we initialize it to False after the call to super __init__.
self._is_rendered = False
def __getstate__(self):
"""
Raise an exception if trying to pickle an unrendered response. Pickle
only rendered data, not the data used to construct the response.
"""
obj_dict = self.__dict__.copy()
if not self._is_rendered:
raise ContentNotRenderedError('The response content must be '
'rendered before it can be pickled.')
for attr in self.rendering_attrs:
if attr in obj_dict:
del obj_dict[attr]
return obj_dict
[docs] def resolve_template(self, template):
"Accepts a template object, path-to-template or list of paths"
if isinstance(template, (list, tuple)):
return select_template(template, using=self.using)
elif isinstance(template, six.string_types):
return get_template(template, using=self.using)
else:
return template
@property
def rendered_content(self):
"""Returns the freshly rendered content for the template and context
described by the TemplateResponse.
This *does not* set the final content of the response. To set the
response content, you must either call render(), or set the
content explicitly using the value of this property.
"""
template = self.resolve_template(self.template_name)
context = self.resolve_context(self.context_data)
content = template.render(context, self._request)
return content
[docs] def add_post_render_callback(self, callback):
"""Adds a new post-rendering callback.
If the response has already been rendered,
invoke the callback immediately.
"""
if self._is_rendered:
callback(self)
else:
self._post_render_callbacks.append(callback)
[docs] 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
@property
def is_rendered(self):
return self._is_rendered
def __iter__(self):
if not self._is_rendered:
raise ContentNotRenderedError(
'The response content must be rendered before it can be iterated over.'
)
return super(SimpleTemplateResponse, self).__iter__()
@property
def content(self):
if not self._is_rendered:
raise ContentNotRenderedError(
'The response content must be rendered before it can be accessed.'
)
return super(SimpleTemplateResponse, self).content
@content.setter
def content(self, value):
"""Sets the content for the response
"""
HttpResponse.content.fset(self, value)
self._is_rendered = True
[docs]class TemplateResponse(SimpleTemplateResponse):
rendering_attrs = SimpleTemplateResponse.rendering_attrs + ['_request']
[docs] def __init__(self, request, template, context=None, content_type=None,
status=None, charset=None, using=None):
super(TemplateResponse, self).__init__(
template, context, content_type, status, charset, using)
self._request = request
Jun 14, 2020