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# 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.
import copy
import json
from django import forms
from django import http
from django import shortcuts
from django.utils import http as utils_http
from django.views import generic
from horizon import exceptions
from horizon.forms import views as hz_views
from horizon.forms.views import ADD_TO_FIELD_HEADER
from horizon import messages
class WorkflowView(hz_views.ModalBackdropMixin, generic.TemplateView):
"""A generic view which handles the intricacies of workflow processing.
.. attribute:: workflow_class
The :class:`~horizon.workflows.Workflow` class which this view handles.
Required.
.. attribute:: template_name
The template to use when rendering this view via standard HTTP
requests. Required.
.. attribute:: ajax_template_name
The template to use when rendering the workflow for AJAX requests.
In general the default common template should be used. Defaults to
``"horizon/common/_workflow.html"``.
.. attribute:: context_object_name
The key which should be used for the workflow object in the template
context. Defaults to ``"workflow"``.
"""
workflow_class = None
template_name = 'horizon/common/_workflow_base.html'
context_object_name = "workflow"
ajax_template_name = 'horizon/common/_workflow.html'
step_errors = {}
def __init__(self):
super().__init__()
if not self.workflow_class:
raise AttributeError("You must set the workflow_class attribute "
"on %s." % self.__class__.__name__)
def get_initial(self):
"""Returns initial data for the workflow.
Defaults to using the GET parameters
to allow pre-seeding of the workflow context values.
"""
return copy.copy(self.request.GET)
def get_workflow(self):
"""Returns the instantiated workflow class."""
extra_context = self.get_initial()
entry_point = self.request.GET.get("step", None)
workflow = self.workflow_class(self.request,
context_seed=extra_context,
entry_point=entry_point)
return workflow
def get_context_data(self, **kwargs):
"""Returns the template context, including the workflow class.
This method should be overridden in subclasses to provide additional
context data to the template.
"""
context = super().get_context_data(**kwargs)
workflow = self.get_workflow()
workflow.verify_integrity()
context[self.context_object_name] = workflow
redirect_to = self.request.GET.get(workflow.redirect_param_name)
# Make sure the requested redirect is safe
if (redirect_to and
not utils_http.url_has_allowed_host_and_scheme(
url=redirect_to,
allowed_hosts=[self.request.get_host()])):
redirect_to = None
context['REDIRECT_URL'] = redirect_to
context['layout'] = self.get_layout()
# For consistency with Workflow class
context['modal'] = 'modal' in context['layout']
if ADD_TO_FIELD_HEADER in self.request.META:
context['add_to_field'] = self.request.META[ADD_TO_FIELD_HEADER]
return context
def get_layout(self):
"""Returns classes for the workflow element in template.
The returned classes are determied based on
the workflow characteristics.
"""
if self.request.is_ajax():
layout = ['modal', ]
else:
layout = ['static_page', ]
if self.workflow_class.wizard:
layout += ['wizard', ]
return layout
def get_template_names(self):
"""Returns the template name to use for this request."""
if self.request.is_ajax():
template = self.ajax_template_name
else:
template = self.template_name
return template
def get_object_id(self, obj):
return getattr(obj, "id", None)
def get_object_display(self, obj):
return getattr(obj, "name", None)
def add_error_to_step(self, error_msg, step):
self.step_errors[step] = error_msg
def set_workflow_step_errors(self, context):
workflow = context['workflow']
for step in self.step_errors:
error_msg = self.step_errors[step]
workflow.add_error_to_step(error_msg, step)
def get(self, request, *args, **kwargs):
"""Handler for HTTP GET requests."""
try:
context = self.get_context_data(**kwargs)
except exceptions.NotAvailable:
exceptions.handle(request)
self.set_workflow_step_errors(context)
return self.render_to_response(context)
def validate_steps(self, request, workflow, start, end):
"""Validates the workflow steps from ``start`` to ``end``, inclusive.
Returns a dict describing the validation state of the workflow.
"""
errors = {}
for step in workflow.steps[start:end + 1]:
if not step.action.is_valid():
errors[step.slug] = dict(
(field, [str(error) for error in errors])
for (field, errors) in step.action.errors.items())
return {
'has_errors': bool(errors),
'workflow_slug': workflow.slug,
'errors': errors,
}
def post(self, request, *args, **kwargs):
"""Handler for HTTP POST requests."""
context = self.get_context_data(**kwargs)
workflow = context[self.context_object_name]
try:
# Check for the VALIDATE_STEP* headers, if they are present
# and valid integers, return validation results as JSON,
# otherwise proceed normally.
validate_step_start = int(self.request.META.get(
'HTTP_X_HORIZON_VALIDATE_STEP_START', ''))
validate_step_end = int(self.request.META.get(
'HTTP_X_HORIZON_VALIDATE_STEP_END', ''))
except ValueError:
# No VALIDATE_STEP* headers, or invalid values. Just proceed
# with normal workflow handling for POSTs.
pass
else:
# There are valid VALIDATE_STEP* headers, so only do validation
# for the specified steps and return results.
data = self.validate_steps(request, workflow,
validate_step_start,
validate_step_end)
return http.HttpResponse(json.dumps(data),
content_type="application/json")
if not workflow.is_valid():
return self.render_to_response(context)
try:
success = workflow.finalize()
except forms.ValidationError:
return self.render_to_response(context)
except Exception:
success = False
exceptions.handle(request)
if success:
msg = workflow.format_status_message(workflow.success_message)
messages.success(request, msg)
else:
msg = workflow.format_status_message(workflow.failure_message)
messages.error(request, msg)
if "HTTP_X_HORIZON_ADD_TO_FIELD" in self.request.META:
field_id = self.request.META["HTTP_X_HORIZON_ADD_TO_FIELD"]
response = http.HttpResponse(content_type="text/plain")
if workflow.object:
data = [self.get_object_id(workflow.object),
self.get_object_display(workflow.object)]
response.content = json.dumps(data)
response["X-Horizon-Add-To-Field"] = field_id
return response
next_url = self.request.POST.get(workflow.redirect_param_name)
return shortcuts.redirect(next_url or workflow.get_success_url())
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