The `AppObject` class

~~~~~~~~~~~~~~~~~~~~~

In general:

* we do not inherit directly from this class but from a more specific

  class such as `AnyEntity`, `EntityView`, `AnyRsetView`,

  `Action`...

* to be recordable, a subclass has to define its own register (attribute

  `__registry__`) and its identifier (attribute `id`). Usually we do not have

  to take care of the register, only the identifier `id`.

We can find a certain number of attributes and methods defined in this class

and common to all the application objects.

At the recording, the following attributes are dynamically added to

the *subclasses*:

* `vreg`, the `vregistry` of the application

* `schema`, the application schema

* `config`, the application configuration

We also find on instances, the following attributes:

* `req`, `Request` instance

* `rset`, the *result set* associated to the object if necessary

* `cursor`, rql cursor on the session

:URL handling:

  * `build_url(method=None, **kwargs)`, returns an absolute URL based on

    the given arguments. The *controller* supposed to handle the response,

    can be specified through the special parameter `method` (the connection

    is theoretically done automatically :).

  * `datadir_url()`, returns the directory of the application data

    (contains static files such as images, css, js...)

  * `base_url()`, shortcut to `req.base_url()`

  * `url_quote(value)`, version *unicode safe* of the function `urllib.quote`

:Data manipulation:

  * `etype_rset(etype, size=1)`, shortcut to `vreg.etype_rset()`

  * `eid_rset(eid, rql=None, descr=True)`, returns a *result set* object for

    the given eid

  * `entity(row, col=0)`, returns the entity corresponding to the data position

    in the *result set* associated to the object

  * `complete_entity(row, col=0, skip_bytes=True)`, is equivalent to `entity` but

    also call the method `complete()` on the entity before returning it

:Data formatting:

  * `format_date(date, date_format=None, time=False)` returns a string for a

    mx date time according to application's configuration

  * `format_time(time)` returns a string for a mx date time according to

    application's configuration

:And more...:

  * `external_resource(rid, default=_MARKER)`, access to a value defined in the

    configuration file `external_resource`

  * `tal_render(template, variables)`, renders a precompiled page template with

    variables in the given dictionary as context

.. note::

  When we inherit from `AppObject` (even not directly), you *always* have to use

  **super()** to get the methods and attributes of the superclasses, and not

  use the class identifier.

  For example, instead of writting: ::

      class Truc(PrimaryView):

          def f(self, arg1):

              PrimaryView.f(self, arg1)

  You'd better write: ::

      class Truc(PrimaryView):

          def f(self, arg1):

              super(Truc, self).f(arg1)