core.prototypes.instanced_module

Module Contents

Classes

InstancedModule

InstancedModule is a base class for modules, which can be passed as instance to the viur-core.
class core.prototypes.instanced_module.InstancedModule(*args, **kwargs)

InstancedModule is a base class for modules, which can be passed as instance to the viur-core.

Normally, the viur-core expects classes from modules and instantiates them during setup. However, there are cases where you want to pass already instantiated classes, i.e. module instances, to the core. For example, to integrate plugins. This is where this base class comes into play. If it is included as an ADDITIONAL base class to the module class, the viur-core accepts an instance of this class. The class itself is then no longer instantiated in the core.

In order to preserve the well-known ViUR module concept, this class overwrites the __init__ method so that it behaves like a classic object constructor. The __call__ method then takes on the role of the conventional __init__ module. However, as each render requires its own module instance, as the render itself is then referenced to this instance via the “render” attribute, several instances are required. Therefore, a copy of the module instance is created using the internal method _viur_clone. This can be changed if necessary. A shadow-copy is created here by default.

Here an example:

from viur.core.prototypes import List
from viur.core.prototypes.instanced_module import InstancedModule


class MyModule(InstancedModule, List):
    def __init__(self, configuration):
        self.configuration = configuration


my_module = MyModule(
    configuration=...
)

As you can see, the configuration parameter is set from outside and not in the class. This may seem a bit strange here, but now imagine that the class definition MyModule is not within the same file but in an imported pip package. Then this instantiation is much easier than using a subclass.

Overwrite the Module.__init__ and do nothing

Can be overwritten as needed, e.g. to assign instance attributes.

__call__(moduleName, modulePath, *args, **kwargs)

Do the instance initialisation

Take the role of Module.__init__ (and call it).

Parameters:

  • moduleName (str) –

  • modulePath (str) –

Return type:

InstancedModule

_viur_clone()

Creates a copy for non-standard renderers.

Since viur keeps one instance per render. Can be overwritten if desired.