%global _empty_manifest_terminate_build 0 Name: python-objproxies Version: 0.9.4 Release: 1 Summary: General purpose proxy and wrapper types License: PSF or ZPL URL: http://github.com/soulrebel/objproxies Source0: https://mirrors.nju.edu.cn/pypi/web/packages/1d/6b/0434d100d411760d4d634e21dc256e259af720887b0c856c5a9b2c97ea30/objproxies-0.9.4.tar.gz BuildArch: noarch %description The ``objproxies`` module provides some useful base classes for creating proxies and wrappers for ordinary Python objects. Proxy objects automatically delegate all attribute access and operations to the proxied object. Wrappers are similar, but can be subclassed to allow additional attributes and operations to be added to the wrapped object. Note that these proxy types are not intended to be tamper-proof; the unproxied form of an object can be readily accessed using a proxy's ``__subject__`` attribute, and some proxy types even allow this attribute to be set (This can be handy for algorithms that lazily create circular structures and thus need to be able to hand out "forward reference" proxies.) Development status ****************** This is Python 3 port of `ProxyTypes `_ wrote by Phillip J. Eby as part of `PEAK `_ for Python 2. The namespace was changed from ``peak.util.proxies`` to ``objproxies``. Other than that it should be a compatible replacement. So far the following was accomplished: * Streamlined files and setup * Ported unittests and doctests * Cleaned up syntax v1.0 TODO +++++++++ * Turn the module in a package, separate functionalities in different modules * Simplify code wherever possible * Get positive feedback from a couple of users Contributions and bug reports are welcome. Testing +++++++ When nose is available all tests can be run using: nosetests3 --with-doctest --doctest-extension=rst . Otherwise standard python will suffice: python -m unittest objproxies_tests.py python -m doctest README.rst Proxy Basics ************ Here's a quick demo of the ``ObjectProxy`` type:: >>> from objproxies import ObjectProxy >>> p = ObjectProxy(42) >>> p 42 >>> isinstance(p, int) True >>> p.__class__ >>> p*2 84 >>> 'X' * p 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX' >>> hex(p) '0x2a' >>> chr(p) '*' >>> p ^ 1 43 >>> p ** 2 1764 As you can see, a proxy is virtually indistinguishable from the object it proxies, except via its ``__subject__`` attribute, and its ``type()``:: >>> p.__subject__ 42 >>> type(p) You can change the ``__subject__`` of an ``ObjectProxy``, and it will then refer to something else:: >>> p.__subject__ = 99 >>> p 99 >>> p-33 66 >>> p.__subject__ = "foo" >>> p 'foo' All operations are delegated to the subject, including ``setattr`` and ``delattr``:: >>> class Dummy: pass >>> d = Dummy() >>> p = ObjectProxy(d) >>> p.foo = "bar" >>> d.foo 'bar' >>> del p.foo >>> hasattr(d,'foo') False Callback Proxies **************** Sometimes, you may want a proxy's subject to be determined dynamically whenever the proxy is used. For this purpose, you can use the ``CallbackProxy`` type, which accepts a callback function and creates a proxy that will invoke the callback in order to get the target. Here's a quick example of a counter that gets incremented each time it's used, from zero to three:: >>> from objproxies import CallbackProxy >>> callback = iter(range(4)).__next__ >>> counter = CallbackProxy(callback) >>> counter 0 >>> counter 1 >>> str(counter) '2' >>> hex(counter) '0x3' >>> counter Traceback (most recent call last): StopIteration As you can see, the callback is automatically invoked on any attempt to use the proxy. This is a somewhat silly example; a better one would be something like a ``thread_id`` proxy that is always equal to the ID # of the thread it's running in. A callback proxy's callback can be obtained or changed via the ``get_callback`` and ``set_callback`` functions:: >>> from objproxies import get_callback, set_callback >>> set_callback(counter, lambda: 42) >>> counter 42 >>> type(get_callback(counter)) Lazy Proxies ************ A ``LazyProxy`` is similar to a ``CallbackProxy``, but its callback is called at most once, and then cached:: >>> from objproxies import LazyProxy >>> def callback(): >>> lazy = LazyProxy(callback) >>> lazy called 42 >>> lazy 42 You can use the ``get_callback`` and ``set_callback`` functions on lazy proxies, but it has no effect if the callback was already called:: >>> set_callback(lazy, lambda: 99) >>> lazy 42 But you can use the ``get_cache`` and ``set_cache`` functions to tamper with the cached value:: >>> from objproxies import get_cache, set_cache >>> get_cache(lazy) 42 >>> set_cache(lazy, 99) >>> lazy 99 Wrappers ******** The ``ObjectWrapper``, ``CallbackWrapper`` and ``LazyWrapper`` classes are similar to their proxy counterparts, except that they are intended to be subclassed in order to add custom extra attributes or methods. Any attribute that exists in a subclass of these classes will be read or written from the wrapper instance, instead of the wrapped object. For example:: >>> from objproxies import ObjectWrapper >>> class NameWrapper(ObjectWrapper): >>> w = NameWrapper(42, "The Ultimate Answer") >>> w 42 >>> print(w) The Ultimate Answer >>> w * 2 84 >>> w.name 'The Ultimate Answer' Notice that any attributes you add must be defined *in the class*. You can't add arbitrary attributes at runtime, because they'll be set on the wrapped object instead of the wrapper:: >>> w.foo = 'bar' Traceback (most recent call last): AttributeError: 'int' object has no attribute 'foo' Note that this means that all instance attributes must be implemented as either slots, properties, or have a default value defined in the class body (like the ``name = None`` shown in the example above. The ``CallbackWrapper`` and ``LazyWrapper`` base classes are basically the same as ``ObjectWrapper``, except that they use a callback or cached lazy callback instead of expecting an object as their subject. ``LazyWrapper`` objects are particularly useful when working with expensive resources, like connections or web browsers, to avoid their creation unless absolutely needed. However resources usually must be released after use by calling a "``close``" method of some sort. In this case the lazy creation could be triggered just when the object is not needed anymore, by the call to ``close`` itself. For this reason when extending ``LazyWrapper`` these methods can be overridden with a ``@lazymethod`` replacement:: >>> from objproxies import LazyWrapper, lazymethod >>> class LazyCloseable(LazyWrapper): >>> import tempfile >>> def openf(): >>> lazyfile = LazyCloseable(openf) >>> lazyfile.tell() 0 >>> lazyfile.close() bye >>> bool(lazyfile) False >>> lazyfile = LazyCloseable(openf) >>> lazyfile.write('wake up') called 7 >>> lazyfile.tell() 7 >>> lazyfile.close() # close for real >>> bool(lazyfile) True Advanced: custom subclasses and mixins ************************************** In addition to all the concrete classes described above, there are also two abstract base classes: ``AbstractProxy`` and ``AbstractWrapper``. If you want to create a mixin type that can be used with any of the concrete types, you should subclass the abstract version and set ``__slots__`` to an empty list:: >>> from objproxies import AbstractWrapper >>> class NamedMixin(AbstractWrapper): Then, when you mix it in with the respective base class, you can add back in any necessary slots, or leave off ``__slots__`` to give the subclass instances a dictionary of their own:: >>> from objproxies import CallbackWrapper, LazyWrapper >>> class NamedObject(NamedMixin, ObjectWrapper): pass >>> class NamedCallback(NamedMixin, CallbackWrapper): pass >>> class NamedLazy(NamedMixin, LazyWrapper): pass >>> print(NamedObject(42, "The Answer")) The Answer >>> n = NamedCallback(callback, "Test") >>> n called 42 >>> n called 42 >>> n = NamedLazy(callback, "Once") >>> n called 42 >>> n 42 Both the ``AbstractProxy`` and ``AbstractWrapper`` base classes work by assuming that ``self.__subject__`` will be the wrapped or proxed object. If you don't want to use any of the standard three ways of defining ``__subject__`` (i.e., as an object, callback, or lazy callback), you will need to subclass ``AbstractProxy`` or ``AbstractWrapper`` and provide your own way of defining ``__subject__``. %package -n python3-objproxies Summary: General purpose proxy and wrapper types Provides: python-objproxies BuildRequires: python3-devel BuildRequires: python3-setuptools BuildRequires: python3-pip %description -n python3-objproxies The ``objproxies`` module provides some useful base classes for creating proxies and wrappers for ordinary Python objects. Proxy objects automatically delegate all attribute access and operations to the proxied object. Wrappers are similar, but can be subclassed to allow additional attributes and operations to be added to the wrapped object. Note that these proxy types are not intended to be tamper-proof; the unproxied form of an object can be readily accessed using a proxy's ``__subject__`` attribute, and some proxy types even allow this attribute to be set (This can be handy for algorithms that lazily create circular structures and thus need to be able to hand out "forward reference" proxies.) Development status ****************** This is Python 3 port of `ProxyTypes `_ wrote by Phillip J. Eby as part of `PEAK `_ for Python 2. The namespace was changed from ``peak.util.proxies`` to ``objproxies``. Other than that it should be a compatible replacement. So far the following was accomplished: * Streamlined files and setup * Ported unittests and doctests * Cleaned up syntax v1.0 TODO +++++++++ * Turn the module in a package, separate functionalities in different modules * Simplify code wherever possible * Get positive feedback from a couple of users Contributions and bug reports are welcome. Testing +++++++ When nose is available all tests can be run using: nosetests3 --with-doctest --doctest-extension=rst . Otherwise standard python will suffice: python -m unittest objproxies_tests.py python -m doctest README.rst Proxy Basics ************ Here's a quick demo of the ``ObjectProxy`` type:: >>> from objproxies import ObjectProxy >>> p = ObjectProxy(42) >>> p 42 >>> isinstance(p, int) True >>> p.__class__ >>> p*2 84 >>> 'X' * p 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX' >>> hex(p) '0x2a' >>> chr(p) '*' >>> p ^ 1 43 >>> p ** 2 1764 As you can see, a proxy is virtually indistinguishable from the object it proxies, except via its ``__subject__`` attribute, and its ``type()``:: >>> p.__subject__ 42 >>> type(p) You can change the ``__subject__`` of an ``ObjectProxy``, and it will then refer to something else:: >>> p.__subject__ = 99 >>> p 99 >>> p-33 66 >>> p.__subject__ = "foo" >>> p 'foo' All operations are delegated to the subject, including ``setattr`` and ``delattr``:: >>> class Dummy: pass >>> d = Dummy() >>> p = ObjectProxy(d) >>> p.foo = "bar" >>> d.foo 'bar' >>> del p.foo >>> hasattr(d,'foo') False Callback Proxies **************** Sometimes, you may want a proxy's subject to be determined dynamically whenever the proxy is used. For this purpose, you can use the ``CallbackProxy`` type, which accepts a callback function and creates a proxy that will invoke the callback in order to get the target. Here's a quick example of a counter that gets incremented each time it's used, from zero to three:: >>> from objproxies import CallbackProxy >>> callback = iter(range(4)).__next__ >>> counter = CallbackProxy(callback) >>> counter 0 >>> counter 1 >>> str(counter) '2' >>> hex(counter) '0x3' >>> counter Traceback (most recent call last): StopIteration As you can see, the callback is automatically invoked on any attempt to use the proxy. This is a somewhat silly example; a better one would be something like a ``thread_id`` proxy that is always equal to the ID # of the thread it's running in. A callback proxy's callback can be obtained or changed via the ``get_callback`` and ``set_callback`` functions:: >>> from objproxies import get_callback, set_callback >>> set_callback(counter, lambda: 42) >>> counter 42 >>> type(get_callback(counter)) Lazy Proxies ************ A ``LazyProxy`` is similar to a ``CallbackProxy``, but its callback is called at most once, and then cached:: >>> from objproxies import LazyProxy >>> def callback(): >>> lazy = LazyProxy(callback) >>> lazy called 42 >>> lazy 42 You can use the ``get_callback`` and ``set_callback`` functions on lazy proxies, but it has no effect if the callback was already called:: >>> set_callback(lazy, lambda: 99) >>> lazy 42 But you can use the ``get_cache`` and ``set_cache`` functions to tamper with the cached value:: >>> from objproxies import get_cache, set_cache >>> get_cache(lazy) 42 >>> set_cache(lazy, 99) >>> lazy 99 Wrappers ******** The ``ObjectWrapper``, ``CallbackWrapper`` and ``LazyWrapper`` classes are similar to their proxy counterparts, except that they are intended to be subclassed in order to add custom extra attributes or methods. Any attribute that exists in a subclass of these classes will be read or written from the wrapper instance, instead of the wrapped object. For example:: >>> from objproxies import ObjectWrapper >>> class NameWrapper(ObjectWrapper): >>> w = NameWrapper(42, "The Ultimate Answer") >>> w 42 >>> print(w) The Ultimate Answer >>> w * 2 84 >>> w.name 'The Ultimate Answer' Notice that any attributes you add must be defined *in the class*. You can't add arbitrary attributes at runtime, because they'll be set on the wrapped object instead of the wrapper:: >>> w.foo = 'bar' Traceback (most recent call last): AttributeError: 'int' object has no attribute 'foo' Note that this means that all instance attributes must be implemented as either slots, properties, or have a default value defined in the class body (like the ``name = None`` shown in the example above. The ``CallbackWrapper`` and ``LazyWrapper`` base classes are basically the same as ``ObjectWrapper``, except that they use a callback or cached lazy callback instead of expecting an object as their subject. ``LazyWrapper`` objects are particularly useful when working with expensive resources, like connections or web browsers, to avoid their creation unless absolutely needed. However resources usually must be released after use by calling a "``close``" method of some sort. In this case the lazy creation could be triggered just when the object is not needed anymore, by the call to ``close`` itself. For this reason when extending ``LazyWrapper`` these methods can be overridden with a ``@lazymethod`` replacement:: >>> from objproxies import LazyWrapper, lazymethod >>> class LazyCloseable(LazyWrapper): >>> import tempfile >>> def openf(): >>> lazyfile = LazyCloseable(openf) >>> lazyfile.tell() 0 >>> lazyfile.close() bye >>> bool(lazyfile) False >>> lazyfile = LazyCloseable(openf) >>> lazyfile.write('wake up') called 7 >>> lazyfile.tell() 7 >>> lazyfile.close() # close for real >>> bool(lazyfile) True Advanced: custom subclasses and mixins ************************************** In addition to all the concrete classes described above, there are also two abstract base classes: ``AbstractProxy`` and ``AbstractWrapper``. If you want to create a mixin type that can be used with any of the concrete types, you should subclass the abstract version and set ``__slots__`` to an empty list:: >>> from objproxies import AbstractWrapper >>> class NamedMixin(AbstractWrapper): Then, when you mix it in with the respective base class, you can add back in any necessary slots, or leave off ``__slots__`` to give the subclass instances a dictionary of their own:: >>> from objproxies import CallbackWrapper, LazyWrapper >>> class NamedObject(NamedMixin, ObjectWrapper): pass >>> class NamedCallback(NamedMixin, CallbackWrapper): pass >>> class NamedLazy(NamedMixin, LazyWrapper): pass >>> print(NamedObject(42, "The Answer")) The Answer >>> n = NamedCallback(callback, "Test") >>> n called 42 >>> n called 42 >>> n = NamedLazy(callback, "Once") >>> n called 42 >>> n 42 Both the ``AbstractProxy`` and ``AbstractWrapper`` base classes work by assuming that ``self.__subject__`` will be the wrapped or proxed object. If you don't want to use any of the standard three ways of defining ``__subject__`` (i.e., as an object, callback, or lazy callback), you will need to subclass ``AbstractProxy`` or ``AbstractWrapper`` and provide your own way of defining ``__subject__``. %package help Summary: Development documents and examples for objproxies Provides: python3-objproxies-doc %description help The ``objproxies`` module provides some useful base classes for creating proxies and wrappers for ordinary Python objects. Proxy objects automatically delegate all attribute access and operations to the proxied object. Wrappers are similar, but can be subclassed to allow additional attributes and operations to be added to the wrapped object. Note that these proxy types are not intended to be tamper-proof; the unproxied form of an object can be readily accessed using a proxy's ``__subject__`` attribute, and some proxy types even allow this attribute to be set (This can be handy for algorithms that lazily create circular structures and thus need to be able to hand out "forward reference" proxies.) Development status ****************** This is Python 3 port of `ProxyTypes `_ wrote by Phillip J. Eby as part of `PEAK `_ for Python 2. The namespace was changed from ``peak.util.proxies`` to ``objproxies``. Other than that it should be a compatible replacement. So far the following was accomplished: * Streamlined files and setup * Ported unittests and doctests * Cleaned up syntax v1.0 TODO +++++++++ * Turn the module in a package, separate functionalities in different modules * Simplify code wherever possible * Get positive feedback from a couple of users Contributions and bug reports are welcome. Testing +++++++ When nose is available all tests can be run using: nosetests3 --with-doctest --doctest-extension=rst . Otherwise standard python will suffice: python -m unittest objproxies_tests.py python -m doctest README.rst Proxy Basics ************ Here's a quick demo of the ``ObjectProxy`` type:: >>> from objproxies import ObjectProxy >>> p = ObjectProxy(42) >>> p 42 >>> isinstance(p, int) True >>> p.__class__ >>> p*2 84 >>> 'X' * p 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX' >>> hex(p) '0x2a' >>> chr(p) '*' >>> p ^ 1 43 >>> p ** 2 1764 As you can see, a proxy is virtually indistinguishable from the object it proxies, except via its ``__subject__`` attribute, and its ``type()``:: >>> p.__subject__ 42 >>> type(p) You can change the ``__subject__`` of an ``ObjectProxy``, and it will then refer to something else:: >>> p.__subject__ = 99 >>> p 99 >>> p-33 66 >>> p.__subject__ = "foo" >>> p 'foo' All operations are delegated to the subject, including ``setattr`` and ``delattr``:: >>> class Dummy: pass >>> d = Dummy() >>> p = ObjectProxy(d) >>> p.foo = "bar" >>> d.foo 'bar' >>> del p.foo >>> hasattr(d,'foo') False Callback Proxies **************** Sometimes, you may want a proxy's subject to be determined dynamically whenever the proxy is used. For this purpose, you can use the ``CallbackProxy`` type, which accepts a callback function and creates a proxy that will invoke the callback in order to get the target. Here's a quick example of a counter that gets incremented each time it's used, from zero to three:: >>> from objproxies import CallbackProxy >>> callback = iter(range(4)).__next__ >>> counter = CallbackProxy(callback) >>> counter 0 >>> counter 1 >>> str(counter) '2' >>> hex(counter) '0x3' >>> counter Traceback (most recent call last): StopIteration As you can see, the callback is automatically invoked on any attempt to use the proxy. This is a somewhat silly example; a better one would be something like a ``thread_id`` proxy that is always equal to the ID # of the thread it's running in. A callback proxy's callback can be obtained or changed via the ``get_callback`` and ``set_callback`` functions:: >>> from objproxies import get_callback, set_callback >>> set_callback(counter, lambda: 42) >>> counter 42 >>> type(get_callback(counter)) Lazy Proxies ************ A ``LazyProxy`` is similar to a ``CallbackProxy``, but its callback is called at most once, and then cached:: >>> from objproxies import LazyProxy >>> def callback(): >>> lazy = LazyProxy(callback) >>> lazy called 42 >>> lazy 42 You can use the ``get_callback`` and ``set_callback`` functions on lazy proxies, but it has no effect if the callback was already called:: >>> set_callback(lazy, lambda: 99) >>> lazy 42 But you can use the ``get_cache`` and ``set_cache`` functions to tamper with the cached value:: >>> from objproxies import get_cache, set_cache >>> get_cache(lazy) 42 >>> set_cache(lazy, 99) >>> lazy 99 Wrappers ******** The ``ObjectWrapper``, ``CallbackWrapper`` and ``LazyWrapper`` classes are similar to their proxy counterparts, except that they are intended to be subclassed in order to add custom extra attributes or methods. Any attribute that exists in a subclass of these classes will be read or written from the wrapper instance, instead of the wrapped object. For example:: >>> from objproxies import ObjectWrapper >>> class NameWrapper(ObjectWrapper): >>> w = NameWrapper(42, "The Ultimate Answer") >>> w 42 >>> print(w) The Ultimate Answer >>> w * 2 84 >>> w.name 'The Ultimate Answer' Notice that any attributes you add must be defined *in the class*. You can't add arbitrary attributes at runtime, because they'll be set on the wrapped object instead of the wrapper:: >>> w.foo = 'bar' Traceback (most recent call last): AttributeError: 'int' object has no attribute 'foo' Note that this means that all instance attributes must be implemented as either slots, properties, or have a default value defined in the class body (like the ``name = None`` shown in the example above. The ``CallbackWrapper`` and ``LazyWrapper`` base classes are basically the same as ``ObjectWrapper``, except that they use a callback or cached lazy callback instead of expecting an object as their subject. ``LazyWrapper`` objects are particularly useful when working with expensive resources, like connections or web browsers, to avoid their creation unless absolutely needed. However resources usually must be released after use by calling a "``close``" method of some sort. In this case the lazy creation could be triggered just when the object is not needed anymore, by the call to ``close`` itself. For this reason when extending ``LazyWrapper`` these methods can be overridden with a ``@lazymethod`` replacement:: >>> from objproxies import LazyWrapper, lazymethod >>> class LazyCloseable(LazyWrapper): >>> import tempfile >>> def openf(): >>> lazyfile = LazyCloseable(openf) >>> lazyfile.tell() 0 >>> lazyfile.close() bye >>> bool(lazyfile) False >>> lazyfile = LazyCloseable(openf) >>> lazyfile.write('wake up') called 7 >>> lazyfile.tell() 7 >>> lazyfile.close() # close for real >>> bool(lazyfile) True Advanced: custom subclasses and mixins ************************************** In addition to all the concrete classes described above, there are also two abstract base classes: ``AbstractProxy`` and ``AbstractWrapper``. If you want to create a mixin type that can be used with any of the concrete types, you should subclass the abstract version and set ``__slots__`` to an empty list:: >>> from objproxies import AbstractWrapper >>> class NamedMixin(AbstractWrapper): Then, when you mix it in with the respective base class, you can add back in any necessary slots, or leave off ``__slots__`` to give the subclass instances a dictionary of their own:: >>> from objproxies import CallbackWrapper, LazyWrapper >>> class NamedObject(NamedMixin, ObjectWrapper): pass >>> class NamedCallback(NamedMixin, CallbackWrapper): pass >>> class NamedLazy(NamedMixin, LazyWrapper): pass >>> print(NamedObject(42, "The Answer")) The Answer >>> n = NamedCallback(callback, "Test") >>> n called 42 >>> n called 42 >>> n = NamedLazy(callback, "Once") >>> n called 42 >>> n 42 Both the ``AbstractProxy`` and ``AbstractWrapper`` base classes work by assuming that ``self.__subject__`` will be the wrapped or proxed object. If you don't want to use any of the standard three ways of defining ``__subject__`` (i.e., as an object, callback, or lazy callback), you will need to subclass ``AbstractProxy`` or ``AbstractWrapper`` and provide your own way of defining ``__subject__``. %prep %autosetup -n objproxies-0.9.4 %build %py3_build %install %py3_install install -d -m755 %{buildroot}/%{_pkgdocdir} if [ -d doc ]; then cp -arf doc %{buildroot}/%{_pkgdocdir}; fi if [ -d docs ]; then cp -arf docs %{buildroot}/%{_pkgdocdir}; fi if [ -d example ]; then cp -arf example %{buildroot}/%{_pkgdocdir}; fi if [ -d examples ]; then cp -arf examples %{buildroot}/%{_pkgdocdir}; fi pushd %{buildroot} if [ -d usr/lib ]; then find usr/lib -type f -printf "/%h/%f\n" >> filelist.lst fi if [ -d usr/lib64 ]; then find usr/lib64 -type f -printf "/%h/%f\n" >> filelist.lst fi if [ -d usr/bin ]; then find usr/bin -type f -printf "/%h/%f\n" >> filelist.lst fi if [ -d usr/sbin ]; then find usr/sbin -type f -printf "/%h/%f\n" >> filelist.lst fi touch doclist.lst if [ -d usr/share/man ]; then find usr/share/man -type f -printf "/%h/%f.gz\n" >> doclist.lst fi popd mv %{buildroot}/filelist.lst . mv %{buildroot}/doclist.lst . %files -n python3-objproxies -f filelist.lst %dir %{python3_sitelib}/* %files help -f doclist.lst %{_docdir}/* %changelog * Wed May 10 2023 Python_Bot - 0.9.4-1 - Package Spec generated