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66 lines
2.5 KiB
ReStructuredText
66 lines
2.5 KiB
ReStructuredText
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Declarative catalogs
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--------------------
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``di.DeclarativeCatalog`` is a catalog of providers that could be defined in
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declarative manner. It should cover most of the cases when list of providers
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that would be included in catalog is deterministic (catalog will not change
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its structure in runtime).
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Definition of declarative catalogs
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Declarative catalogs have to extend base declarative catalog class -
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``di.DeclarativeCatalog``.
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Providers have to be defined like catalog's class attributes. Every provider in
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catalog has name. This name should follow ``some_provider`` convention,
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that is standard naming convention for attribute names in Python.
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.. note::
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It might be useful to add such ``""":type: di.Provider -> Object1"""``
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docstrings just on the next line after provider's definition. It will
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help code analyzing tools and IDE's to understand that variable above
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contains some callable object, that returns particular instance as a
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result of its call.
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Here is an simple example of declarative catalog with several factories:
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.. image:: /images/catalogs/declarative.png
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:width: 85%
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:align: center
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.. literalinclude:: ../../examples/catalogs/declarative.py
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:language: python
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Declarative catalogs API
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~~~~~~~~~~~~~~~~~~~~~~~~
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``di.DeclarativeCatalog`` has several features that could be useful for some
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kind of operations on catalog's providers:
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- ``di.DeclarativeCatalog.providers`` is read-only attribute that contains
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``dict`` of all catalog providers, including providers that are inherited
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from parent catalogs, where key is the name of provider and value is
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provider itself.
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- ``di.DeclarativeCatalog.cls_providers`` is read-only attribute contains
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``dict`` of current catalog providers, where key is the name of provider
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and value is provider itself.
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- ``di.DeclarativeCatalog.inherited_providers`` is read-only attribute
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contains ``dict`` of all providers that are inherited from parent catalogs,
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where key is the name of provider and value is provider itself.
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- ``di.DeclarativeCatalog.filter(provider_type=di.Provider)`` is a class
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method that could be used for filtering catalog providers by provider types
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(for example, for getting all ``di.Factory`` providers).
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``di.DeclarativeCatalog.filter()`` method use
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``di.DeclarativeCatalog.providers``.
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Example:
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.. image:: /images/catalogs/declarative_api.png
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:width: 100%
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:align: center
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.. literalinclude:: ../../examples/catalogs/declarative_api.py
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:language: python
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