Metadata-Version: 1.1
Name: persisting-theory
Version: 0.2.1
Summary: Registries that can autodiscover values accross your project apps
Home-page: http://code.eliotberriot.com/eliotberriot/persisting-theory
Author: Eliot Berriot
Author-email: contact@eliotberriot.com
License: BSD
Description: Introduction
        ============
        
        Persisting-theory is a small python utility designed to automate data discovering and access inside a list of packages. Use case: you are building an application that will have pluggable components. You want to allow these components to register data so it can be accessed by any other component of your app.
        
        If you ever used Django framework, you may remember this::
        
            from django.contrib import admin
            admin.autodiscover()
        
        Basically, persisting-theory will do the same, except that it let you declare what you want to autodiscover.
        
        Okay, I'm bad at explaining things, and english is not my mother tongue. Let's build a simple example.
        
        Quickstart
        ==========
        
        Install
        *******
        
        Install the package from `PyPi <https://pypi.python.org/pypi/persisting-theory/>`_. via pip (or any other tool)::
        
            pip install persisting-theory
        
        Persisting-theory does not require any dependency but a python installation (it has been tested on python 2.7 and python 3.2).
        
        Setup
        *****
        
        A basic setup::
        
            # registries.py
        
            from persiting_theory import Registry
        
            class CallbacksRegistry(Registry):
                """
                    Allow your apps to register callbacks
                """
                # the package where the registry will try to find callbacks in each app
                look_into = "callbacks_registry"
        
            callbacks_registry = CallbacksRegistry()
        
        
            # app1/callbacks_registry.py
        
            from registries import callbacks_registry
        
            @callbacks_registry.register
            def dog():
                print("Wouf")
        
        
            # app2/callbacks_registry.py
        
            from registries import callbacks_registry
        
            @callbacks_registry.register
            def cat():
                print("Meow")
        
        
            # dosomething.py
        
            from registries import callbacks_registry
            
            APPS = (
                'app1',
                'app2',
            )
            
            # Trigger autodiscovering process
            callbacks_registry.autodiscover(APPS)
        
            for callback in callbacks_registry.values():
                callback()
        
                # Wouf
                # Meow
        
        API
        ===
        
        ``Registry`` inherits from python built-in `collections.OrderedDict`, which means you can use regular dict methods to access registered data::
        
            callbacks_registry.get("dog")()  #  will print Wouf
            assert callbacks_registry.get("chicken", None) is None
        
        Registry.register()
        *******************
        
        You can use this function as a decorator for registering functions and classes::
        
            from persisting_theory import Registry
        
            class AwesomeRegistry(Registry):
                pass
        
            r = AwesomeRegistry()
        
            # register a class
            @r.register
            class AwesomeClass:
                pass
        
            # register a function
            @r.register
            def awesome_function():
                pass
        
            # By default, the key in the registry for a given value is obtained from the function or class name, if possible
        
            assert r.get("AwesomeClass") == AwesomeClass
            assert r.get("awesome_function") == awesome_function
        
            # You can override this behaviour:
        
            @r.register(name="Chuck")
            class AwesomeClass:
                pass
        
            @r.register(name="Norris")
            def awesome_function():
                pass
        
            assert r.get("Chuck") == AwesomeClass
            assert r.get("Norris") == awesome_function
        
        
            # You can also use the register method as is
        
            awesome_var = "Chuck Norris"
            r.register(awesome_var, name="Who am I ?")
        
            assert r.get("Who am I ?") == awesome_var
        
            # I f you are not registering a function or a class, you MUST provide a name argument
        
        Registry.validate()
        *******************
        
        By default, a registry will accept any registered value. Sometimes, it's not what you want, so you can restrict what kind of data your registry accepts::
        
            from persisting_theory import Registry
        
            class StartsWithAwesomeRegistry(Registry):
        
                def validate(self, data):
                    if isinstance(data, str):
                        return data.startswith("awesome")
                    return False
        
            r = StartsWithAwesomeRegistry()
        
            # will pass registration
            r.register("awesome day", name="awesome_day")
        
            # will fail and raise ValueError
            r.register("not so awesome day", name="not_so_awesome_day")
        
        Registry.prepare_data()
        ***********************
        
        If you want to manipulate your data before registering it, override this method. In this example, we prefix every registered string with 'hello'::
        
            from persisting_theory import Registry
        
            class HelloRegistry(Registry):
        
                def prepare_data(self, data):
                    return 'hello ' + data 
        
            r = HelloRegistry()
        
            class Greeting:
                def __init__(self, first_name):
                    self.first_name = first_name
        
        
            r.register(Greeting('World'), name="world")
            r.register(Greeting('Eliot'), name="eliot")
        
            assert r.register.get('world') == "hello World"
            assert r.register.get('eliot') == "hello Eliot"
        
        
        Registry.prepare_name()
        ***********************
        
        In a similar way, you can manipulate the name of registered data. This can help if you want to avoid repetitions. Let's improve our previous example::
        
            from persisting_theory import Registry
        
            class HelloRegistry(Registry):
        
                def prepare_data(self, data):
                    return 'hello ' + data 
        
                def prepare_name(self, data, name=None):
                    return self.data.first_name.lower()
        
            r = HelloRegistry()
        
            class Greeting:
                def __init__(self, first_name):
                    self.first_name = first_name
        
        
            r.register(Greeting('World'))
            r.register(Greeting('Eliot'))
        
            assert r.register.get('world') == "hello World"
            assert r.register.get('eliot') == "hello Eliot"
        
        Going meta
        **********
        
        If you have multiple registries, or want to allow your apps to declare their own registries, this is for you::
        
            # registries.py
        
            from persisting_theory import meta_registry, Registry
        
            class RegistryA(Registry):
                look_into = "a"
            
            class RegistryB(Registry):
                look_into = "b"
        
            registry_a = RegistryA()
            meta_registry.register(registry_a, name="registry_a")
        
            registry_b = RegistryB()
            meta_registry.register(registry_b, name="registry_b")
        
        
            # dosomethingelse.py
        
            from persisting_theory import meta_registry
        
            # will import registries declared in `registries` packages, and trigger autodiscover() on each of them
            meta_registry.autodiscover(apps=("app1", "app2"))
        
        
        What the hell is that name ?
        ============================
        
        It's an anagram for "python registries". 
        
        Contribute
        ==========
        
        Contributions, bug reports, and "thank you" are welcomed. Feel free to contact me at <contact@eliotberriot.com>.
        
        License
        =======
        
        The project is licensed under BSD licence.
Platform: UNKNOWN
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: BSD License
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3.4
