zope.app.module 3.5.0

Zope 3 persistent code/module support

Detailed Documentation

The Module Manager

One can simply create a new module manager by instantiating it:

>>> from zope.app.module.manager import ModuleManager
>>> manager = ModuleManager()

If I create the manager without an argument, there is no source code:

>>> manager.source
''

When we add some code

>>> manager.source = """\n
... foo = 1
... def bar(): return foo
... class Blah(object):
...     def __init__(self, id): self.id = id
...     def __repr__(self): return 'Blah(id=%s)' % self.id
... """

we can get the compiled module and use the created objects:

>>> module = manager.getModule()
>>> module.foo
1
>>> module.bar()
1
>>> module.Blah('blah')
Blah(id=blah)

We can also ask for the name of the module:

>>> manager.name
>>> module.__name__

But why is it None? Because we have no registered it yet. Once we register and activate the registration a name will be set:

>>> from zope.app.testing import setup
>>> root = setup.buildSampleFolderTree()
>>> root_sm = setup.createSiteManager(root)

>>> from zope.app.module import interfaces
>>> manager = setup.addUtility(root_sm, 'mymodule',
...                            interfaces.IModuleManager, manager)

>>> manager.name
'mymodule'

>>> manager.getModule().__name__
'mymodule'

Next, let's ensure that the module's persistence works correctly. To do that let's create a database and add the root folder to it:

>>> from ZODB.tests.util import DB
>>> db = DB()
>>> conn = db.open()
>>> conn.root()['Application'] = root

>>> import transaction
>>> transaction.commit()

Let's now reopen the database to test that the module can be seen from a different connection.

>>> conn2 = db.open()
>>> root2 = conn2.root()['Application']
>>> module2 = root2.getSiteManager().queryUtility(
...     interfaces.IModuleManager, 'mymodule').getModule()
>>> module2.foo
1
>>> module2.bar()
1
>>> module2.Blah('blah')
Blah(id=blah)

Module Lookup API

The way the persistent module framework hooks into Python is via module registires that behave pretty much like sys.modules. Zope 3 provides its own module registry that uses the registered utilities to look up modules:

>>> from zope.app.module import ZopeModuleRegistry
>>> ZopeModuleRegistry.findModule('mymodule')

But why did we not get the module back? Because we have not set the site yet:

>>> from zope.app.component import hooks
>>> hooks.setSite(root)

Now it will find the module and we can retrieve a list of all persistent module names:

>>> ZopeModuleRegistry.findModule('mymodule') is module
True
>>> ZopeModuleRegistry.modules()
[u'mymodule']

Additionally, the package provides two API functions that look up a module in the registry and then in sys.modules:

>>> import zope.app.module
>>> zope.app.module.findModule('mymodule') is module
True
>>> zope.app.module.findModule('zope.app.module') is zope.app.module
True

The second function can be used to lookup objects inside any module:

>>> zope.app.module.resolve('mymodule.foo')
1
>>> zope.app.module.resolve('zope.app.module.foo.resolve')

In order to use this framework in real Python code import statements, we need to install the importer hook, which is commonly done with an event subscriber:

>>> import __builtin__
>>> event = object()
>>> zope.app.module.installPersistentModuleImporter(event)
>>> __builtin__.__import__ # doctest: +ELLIPSIS
<bound method ZopePersistentModuleImporter.__import__ of ...>

Now we can simply import the persistent module:

>>> import mymodule
>>> mymodule.Blah('my id')
Blah(id=my id)

Finally, we unregister the hook again:

>>> zope.app.module.uninstallPersistentModuleImporter(event)
>>> __builtin__.__import__
<built-in function __import__>

>>> from zope.app.module.manager import ModuleManager
>>> manager = ModuleManager()
>>> source = """\n

>>> from zope.app.testing import setup
>>> from zope.app.module import interfaces
>>> root = setup.buildSampleFolderTree()
>>> root_sm = setup.createSiteManager(root)
>>> manager = setup.addUtility(root_sm, u'foo',

>>> module = manager.getModule()
>>> module

3.5.0 (2009-02-01)

• Use zope.container instead of zope.app.container.

3.4.0 (2007-10-25)

• Initial release independent of the main Zope tree.