plone.server uses interfaces to abstract and define various things including content. Interfaces are useful when defining api contracts, using inheritance, defining schema/behaviors and being able to define which content your services are used for.

In the services example, you’ll notice the use of context=ISite for the service decorator configuration. In that case, it’s to tell plone.server that the service is only defined for a site object.

Common interfaces

Interfaces you will be interested in defining services for are:

  • plone.server.interface.IDatabase: A database contains the site objects
  • plone.server.interface.ISite: Site content object
  • plone.server.interface.IResource: Base interface for all content
  • plone.server.interface.IContainer: Base interface for content that can contain other content
  • plone.server.interface.IRegistry: Registry object interface
  • plone.server.interface.IDefaultLayer: Layers are an interface applied to the request object. IDefaultLayer is the base default layer applied to the request object.