def get_allowed(sender, obj):
workflow = get_workflow_by_instance(obj)
obj_state = getattr(obj, workflow.state_attr_name)
check_result = dict(
(c, c(obj, sender))
for c in workflow.get_checkers_by_state(obj_state))
messages = []
for checker, message in workflow.get_available_messages(obj_state):
if checker(obj, sender, cache=check_result):
spec = workflow.get_message_spec(message)
messages.append({'id': spec.id, 'title': unicode(spec), 'rank': spec.rank})
resources = []
for resource in workflow.get_available_resources(obj_state):
if resource.permission_checker(obj, sender, cache=check_result):
resources.append(
{
'id': resource.id,
'description': resource.description,
'slug': resource.slug,
})
return {'allowed_messages': messages,
'allowed_resources': resources}
def get_message_specs_for_many(sender, objects):
allowed_map = get_allowed_messages_for_many(sender, objects)
for obj in objects:
workflow = get_workflow_by_instance(obj)
allowed_map[obj] = map(workflow.get_message_spec, allowed_map[obj])
return allowed_map
def get_allowed_messages(sender, obj, cache=None):
workflow = get_workflow_by_instance(obj)
if cache is None:
cache = dict((c, c(obj, sender)) for c in
workflow.get_message_checkers_by_state(obj.state))
for checker, message in workflow.get_available_messages(obj.state):
if checker(obj, sender, cache=cache):
yield message
def get_allowed_resources(sender, obj):
workflow = get_workflow_by_instance(obj)
check_result = dict((c, c(obj, sender)) for c in
workflow.get_checkers_by_state(obj.state))
for resource in workflow.get_available_resources(obj.state):
if resource.permission_checker(obj, sender, cache=check_result):
yield resource
def start_workflow(obj, sender, start_message_params=None):
if start_message_params is None:
start_message_params = {}
workflow = get_workflow_by_instance(obj)
if isinstance(workflow.start_workflow, basestring):
start_message_id = workflow.start_workflow
elif callable(workflow.start_workflow):
start_message_id = workflow.start_workflow(obj, sender)
else:
start_message_id = DEFAULT_START_MESSAGE
return dispatch.dispatch(obj, sender, start_message_id,
start_message_params)
def wrapper(obj, sender, edit_fields=None, **kwargs):
handler_result = handler(obj, sender, **kwargs)
workflow = get_workflow_by_instance(obj)
if not edit_fields:
return handler_result
else:
if isinstance(handler_result, STATE_TYPE_CONSTRAINT):
edit_fields['state'] = handler_result
return workflow.make_updater(edit_fields)
else:
assert callable(handler_result)
updater = workflow.make_updater(edit_fields)
return chained_apply((updater, handler_result))
def perform_side_effect(old_obj, new_obj, message, workflow=None, extra_context=None, handler_result=None):
if workflow is None:
workflow = get_workflow_by_instance(new_obj)
old_state = getattr(old_obj, workflow.state_attr_name)
new_state = getattr(new_obj, workflow.state_attr_name)
(transactional_effects, deferrable_effects) = workflow.library.get_effects_for_transition(
old_state, new_state, message.id
)
if not transactional_effects and not deferrable_effects:
logger.info(u"Effect undefined: object id %s, state %s -> %s", new_obj.id, old_state, new_state)
return [], []
if extra_context is None:
extra_context = {}
effect_kwargs = dict(
old_obj=old_obj,
obj=new_obj,
sender=message.sender,
params=message.params,
message_spec=message.spec,
extra_context=extra_context,
handler_result=handler_result,
)
if transactional_effects:
performed = [_perform_side_effect(effect, effect_kwargs) for effect in deferrable_effects]
else:
performed = []
if deferrable_effects:
deferred = (_perform_side_effect(effect, effect_kwargs) for effect in deferrable_effects)
else:
deferred = []
return performed, deferred
def get_action_form_html(obj, sender):
workflow_type = obj.workflow_type
workflow = get_workflow_by_instance(obj)
allowed_context = get_allowed_messages(sender, obj)
t = template_loader.select_template(
('workflows/%s/form_%s.html' % (workflow_type, obj.state),
'workflows/%s/form.html' % workflow_type,
'workflows/form.html'))
allowed_messages = allowed_context['allowed_messages']
if not allowed_messages:
raise NoAvailableMessagesError(obj.id, sender)
if callable(workflow.formcls_factory):
form_cls = workflow.formcls_factory(allowed_messages)
form = form_cls(instance=obj)
else:
# get all form subclasses from message validators, throw away duplicates
bases = tuple(set(ms.validator_cls for ms in allowed_messages
if issubclass(ms.validator_cls, forms.BaseForm)))
if bases:
# join them all in one mixin class
mixin_form_cls = type('WorkflowObjectMixinForm', bases, {})
# instantiate it and put instance as argument (requires ModelForm subclass to be in bases)
if issubclass(mixin_form_cls, forms.ModelForm):
form = mixin_form_cls(instance=obj)
else:
form = mixin_form_cls(initial=obj.__dict__)
else:
form = forms.Form()
dict_context = {'form': form, 'instance': obj}
dict_context.update(allowed_context)
context = Context(dict_context)
return t.render(context)
def is_valid_message(obj, message_id):
workflow = get_workflow_by_instance(obj)
return workflow.is_valid_message(message_id, obj.state)
def get_message_specs(sender, obj):
workflow = get_workflow_by_instance(obj)
return [workflow.get_message_spec(mid)
for mid in get_allowed_messages(sender, obj)]
def workflow(self):
if not self._workflow:
self._workflow = get_workflow_by_instance(self)
return self._workflow
def dispatch_message(obj, message,
extra_context=None,
transactional_side_effect=TRANSACTIONAL_SIDE_EFFECT,
need_lock_object=USE_SELECT_FOR_UPDATE,
defer_side_effect=False,
revision_manager=None):
'''
Gets an object and message and performs all actions specified by
object's workflow.
:param obj:
Object that receives message. Must be an instance of
:py:class:`yawf.base_model.WorkflowAwareModelBase`
:param message:
:py:class:`yawf.messages.Message` instance that incapsulates message sender and parameters
:return:
Tuple of three values:
* new object instance (after state transition)
* transition result (returned by handler object)
* side effects results
'''
logger.debug(u"Backend got message from %s to %s: %s %s",
smart_unicode(message.sender), smart_unicode(obj),
message.id, smart_unicode(message.raw_params))
# can raise WorkflowNotLoadedError
workflow = get_workflow_by_instance(obj)
# validate data and filter out trash
message.clean(workflow, obj)
# dehydrate message params for serializing
message.dehydrate_params(workflow, obj)
# find a transition handler, can raise handler-related errors
handler = get_handler(workflow, message, obj)
# fetch a transition, can raise app-specific handler errors
handler_result = apply(handler, (obj, message.sender), message.params)
# if handler returns None - do nothing
if handler_result is None:
raise MessageIgnored(message)
# if handler returns type appropriate for state (string) - change state
if isinstance(handler_result, STATE_TYPE_CONSTRAINT):
if workflow.is_valid_state(handler_result):
def state_transition(obj):
setattr(obj, workflow.state_attr_name, handler_result)
obj.save()
return obj
else:
raise IllegalStateError(handler_result)
# if handler returns callable, perform it as single transaction
elif callable(handler_result):
state_transition = handler_result
else:
raise WrongHandlerResultError(handler_result)
if defer_side_effect:
transition_ = transactional_transition
transactional_side_effect = False
else:
transition_ = transition
if revision_manager is None:
revision_manager = default_revision_manager
with revision_manager() as m:
new_obj, transition_result, side_effect_result =\
transition_(
workflow, obj, message, state_transition,
extra_context=extra_context,
transactional_side_effect=transactional_side_effect,
need_lock_object=need_lock_object)
if MESSAGE_LOG_ENABLED:
log_record = log_message(
sender=workflow.id,
workflow=workflow,
message=message,
instance=obj,
new_instance=new_obj,
transition_result=transition_result)
m.bind_revision(log_record)
else:
log_record = None
# TODO: send_robust + logging?
message_handled.send(
sender=workflow.id,
workflow=workflow,
message=message,
instance=obj,
new_instance=new_obj,
transition_result=transition_result,
side_effect_result=side_effect_result,
log_record=log_record)
return new_obj, transition_result, side_effect_result
def get_resource(obj, resource_id):
workflow = get_workflow_by_instance(obj)
return workflow.get_resource(obj.state, resource_id)
