The surf.session Module

class surf.session.Session(default_store=None, mapping=None, auto_persist=False, auto_load=False)

Bases: object

The Session will manage the rest of the components in SuRF, it also acts as the type factory for surf, the resources will walk the graph in a lazy manner based on the session that they are bound to (the last created session).

Create a new session object that handles the creation of types and instances, also the session binds itself to the Resource objects to allow the Resources to access the data store and perform lazy loading of results.

Note

The session object behaves like a dict when it comes to managing the registered stores.

auto_load

Toggle auto_load (no need to explicitly call load, resources are loaded from the store automatically on creation) on or off. Accepts boolean values.

auto_persist

Toggle auto_persistence (no need to explicitly call commit, resources are persisted to the store each time a modification occurs) on or off. Accepts boolean values.

close()

Close the session.

Note

It is good practice to close the session when it’s no longer needed. Remember: upon closing the session all resources will lose the ability to reference the session thus the store and the mapping.

commit()

Commits all changes. In essence the method updates all the dirty registered resources.

default_store

The default store of the session.

See default_store_key to see how the default store is selected.

default_store_key

The default store key of the session.

If it is set explicitly on session creation it is returned, else the first store key is returned. If no stores are in the session None is returned.

get_class(uri, store=None, classes=None)

See surf.session.Session.map_type(). The uri parameter can be any of the following:

• a URIRef
• a Resource

• a string of the form

  • a URI
  • a Resource class name eg: SiocPost
  • a namespace_symbol type string eg: sioc_post

get_resource(subject, concept=None, store=None, graph=None, block_auto_load=False, context=None, classes=None)

Same as map_type but set the resource from the graph.

keys()

The keys that are assigned to the managed stores.

load_resource(uri, subject, store=None, data=None, file=None, location=None, format=None, classes=None)

Create an instance of the class specified by uri, while subject is the subject of the new resource instance.

The other parameters: data, file, location and format are identical in role to the parameters in surf.resource.Resource.load_from_source().

The classes parameter represents the list of base classes of this resource, and is passed further to surf.session.Session.map_type()

The internal properties are set according to the ones specified by the source.

map_instance(concept, subject, store=None, classes=None, block_auto_load=False, context=None)

Create an instance of the class specified by uri and classes to be inherited, see map_type for more information.

map_type(uri, store=None, classes=None)

Create and return a class based on the uri given.

Also will add the classes to the inheritance list.