Advance Guide¶

StateField¶

StateField is a model field defined in django-river, which prepares everything for you. Whenever you put this field into a model object, the model converts into a workflow model. The model have some workflow specialized properties, methods and relations.

Arguments¶

Arguments	Description
state_model	You can change your state model. State model in `django-river` is used as default. It is recomended to use default one.

The Model Injections¶

django-river injects some properties, relations and methods into your model class. This means, ther is gonna be special workflow properties, relations and methods in your model objects. Assume that your model class is Ticket; When you have a ticket object, you can access the injections like ticket.any_injection_below or ticket.any_injection_below.all() or ticket.any_injection_below().

Properties:¶

Name	Return Type	Description
`on_initial_state:`	`boolean`	Defines your model object is on initial states or not.
`on_final_state:`	`boolean`	Defines your model object is on final states or not.
`on_initial_proceedings:`	`Proceeding Queryset`	Returns initial proceeding objects.
`on_final_proceedings:`	`Proceeding Queryset`	Returns final proceeding objects.
`next_proceedings:`	`Proceeding Queryset`	Returns next proceedings objects according to the current state.

Methods:¶

Name	Return Type	Parameters	Description
`proceed:`	`boolean`	``user``(must): User is gonna proceed, ``next_state``(not always)	Defines your model object is on initial states or not.

Relations:¶

Name	Type	Description
`proceedings:`	`GenericRelation`	To Proceeding model.
`proceeding_tract:`	`ForeignKey`	To Proceeding Track model

Signals¶

pre_transition: it is fired before any transition occured.

Args	Description
workflow_object	Your object on transition
field	Field which you registered object for
source_state	Transition source state object
destination_state	Transition destination state object
proceeder	Proceeding object

post_transition: it is fired before any transition occured.

Args	Description
workflow_object	Your object on transition
field	Field which you registered object for
source_state	Transition source state object
destination_state	Transition destination state object
proceeder	Proceeding object

pre_proceeded: it is fired before any is proceeded. Transition does not have to be occured.

Args	Description
workflow_object	Your object proceeded
field	Field which you registered object for
proceeder	Proceeding object
track	Proceeding track object

post_proceeded: it is fired before any is proceeded. Transition does not have to be occured.

Args	Description
workflow_object	Your object proceeded
field	Field which you registered object for
proceeder	Proceeding object
track	Proceeding track object

pre_final: it is fired before any workflow is completed.

Args	Description
workflow_object	Your object on final
field	Field which you registered object for

post_final: it is fired before any workflow is completed.

Args	Description
workflow_object	Your object on final
field	Field which you registered object for

Handlers¶

Handlers are different from django-river. These are for spesific object, spesific source_state, spesific destination_state etc. It is fired when the condition is matched.

PreCompletedHandler¶

Before an object is on final state, if the condition is match; means object is suitable, it is fired;

from river.handlers.completed import PreCompletedHandler

def handler(my_object,field,*args,**kwargs):
        do_something_with(object,field)

PreCompletedHandler.register(handler,my_object,'my_state_field')

register method parameter**

Args	Description
workflow_object	Your object	Required
field	Field which you registered object for	Required

PostCompletedHandler¶

After an object is on final state, if the condition is match; means object is suitable, it is fired;

from river.handlers.completed import PostCompletedHandler

def handler(my_object,field,*args,**kwargs):
    do_something_with(object,field)

PostCompletedHandler.register(handler,my_object,'my_state_field')

`register` method parameter

Args	Description
workflow_object	Your object	Required
field	Field which you registered object for	Required

PreTransitionHandler¶

Before any transition occurred, if the condition is match; means object, source_state,destination state are suitable, it is fired;

from river.handlers.transition import PreTransitionHandler

def handler(my_object,field,*args,**kwargs):
    do_something_with(object,field)

PreTransitionHandler.register(handler,my_object,'my_state_field')

`register` method parameter

Args	Description
workflow_object	Your object proceeded	Required
field	Field which you registered object for	Required
source_state	Source state of the tranition	Optional
desination_satte	Destinatio state of the tranition	Optional

PostTransitionHandler¶

After any transition occurred, if the condition is match; means object, source_state,destination state are suitable, it is fired;

from river.handlers.transition import PostTransitionHandler

def handler(my_object,field,*args,**kwargs):
    do_something_with(object,field)

PostTransitionHandler.register(handler,my_object,'my_state_field')

`register` method parameter

Args	Description
workflow_object	Your object proceeded	Required
field	Field which you registered object for	Required
source_state	Source state of the tranition	Optional
desination_satte	Destinatio state of the tranition	Optional

Handler Backends¶

Handlers can be persisted into different sources. This functionality is added for multiprocessing. Now, backends supports multiprocessing can be implemented.

Backend	Multiprocessing	Path
`MemoryHandlerBackend`	No	`river.handlers.backends.memory.MemoryHandlerBackend`
`DatabaseHandlerBackend`	Yes	`river.handlers.backends.database.DatabaseHandlerBackend`

Default backend is MemoryHandlerBackend which does not supports multiprocessing. It can be updated in settings file;

RIVER_HANDLER_BACKEND = {
    'backend':'river.handlers.backends.database.DatabaseHandlerBackend'
}