deb-horizon/horizon/views.py
Sam Betts 168aa7e162 Document and improve PageTitleMixin readability
This is a follow up patch to https://review.openstack.org/#/c/142802
that adds documentation and also improves code readability in the
PageTitleMixin.

Change-Id: Iac7666252b5ceb9611e0688ef90173edf90475d9
Closes-Bug: 1420744
2015-02-11 16:16:20 +00:00

105 lines
3.8 KiB
Python

# Copyright 2012 Nebula, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
from django import shortcuts
from django import template
from django.utils import encoding
from django.views import generic
import horizon
from horizon import exceptions
class PageTitleMixin(object):
"""A mixin that renders out a page title into a view.
Many views in horizon have a page title that would ordinarily be
defined and passed through in get_context_data function, this often
leads to a lot of duplicated work in each view.
This mixin standardises the process of defining a page title, letting
views simply define a variable that is rendered into the context for
them.
There are cases when page title in a view may also display some context
data, for that purpose the page_title variable supports the django
templating language and will be rendered using the context defined by the
views get_context_data.
"""
page_title = ""
def render_context_with_title(self, context):
"""This function takes in a context dict and uses it to render the
page_title variable, it then appends this title to the context using
the 'page_title' key. If there is already a page_title key defined in
context received then this function will do nothing.
"""
if "page_title" not in context:
con = template.Context(context)
# NOTE(sambetts): Use force_text to ensure lazy translations
# are handled correctly.
temp = template.Template(encoding.force_text(self.page_title))
context["page_title"] = temp.render(con)
return context
def render_to_response(self, context):
"""This is an override of the default render_to_response function that
exists in the django generic views, this is here to inject the
page title into the context before the main template is rendered.
"""
context = self.render_context_with_title(context)
return super(PageTitleMixin, self).render_to_response(context)
class HorizonTemplateView(PageTitleMixin, generic.TemplateView):
pass
class HorizonFormView(PageTitleMixin, generic.FormView):
pass
def user_home(request):
"""Reversible named view to direct a user to the appropriate homepage."""
return shortcuts.redirect(horizon.get_user_home(request.user))
class APIView(HorizonTemplateView):
"""A quick class-based view for putting API data into a template.
Subclasses must define one method, ``get_data``, and a template name
via the ``template_name`` attribute on the class.
Errors within the ``get_data`` function are automatically caught by
the :func:`horizon.exceptions.handle` error handler if not otherwise
caught.
"""
def get_data(self, request, context, *args, **kwargs):
"""This method should handle any necessary API calls, update the
context object, and return the context object at the end.
"""
return context
def get(self, request, *args, **kwargs):
context = self.get_context_data(**kwargs)
try:
context = self.get_data(request, context, *args, **kwargs)
except Exception:
exceptions.handle(request)
return self.render_to_response(context)