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Allow a stanza plugin to override a parent's interfaces.

Browse source 
Each interface, say foo, may be overridden in three ways:
    set_foo
    get_foo
    del_foo

To declare an override in a plugin, add the class field
overrides as so:
    overrides = ['set_foo', 'del_foo']

Each override must have a matching set_foo(), etc method
for implementing the new behaviour.

To enable the overrides for a particular parent stanza,
pass the option overrides=True to register_stanza_plugin.

    register_stanza_plugin(Stanza, Plugin, overrides=True)

Example code:

class Test(ElementBase):

    name = 'test'
    namespace = 'testing'
    interfaces = set(('foo', 'bar'))
    sub_interfaces = set(('bar',))

class TestOverride(ElementBase):

    name = 'test-override'
    namespace = 'testing'
    plugin_attrib = 'override'
    interfaces = set(('foo',))
    overrides = ['set_foo']

    def setup(self, xml):
        # Don't include an XML element in the parent stanza
        # since we're adding just an attribute.
        # If adding a regular subelement, no need to do this.
        self.xml = ET.Element('')

    def set_foo(self, value):
        print("overrides!")
        self.parent()._set_attr('foo', 'override-%s' % value)

register_stanza_plugin(Test, TestOverride, overrides=True)

Example usage:
>>> t = TestStanza()
>>> t['foo'] = 'bar'
>>> t['foo']
'override-bar'
This commit is contained in:
Lance Stout 2011-03-24 12:25:17 -04:00
parent 84e2589f22
commit 6d45971411
2 changed files with 167 additions and 32 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

102
sleekxmpp/xmlstream/stanzabase.py
View file

@ -24,24 +24,32 @@ log = logging.getLogger(__name__)
XML_TYPE = type(ET.Element('xml'))
def register_stanza_plugin(stanza, plugin, iterable=False):
def register_stanza_plugin(stanza, plugin, iterable=False, overrides=False):
"""
Associate a stanza object as a plugin for another stanza.
Arguments:
stanza -- The class of the parent stanza.
plugin -- The class of the plugin stanza.
iterable -- Indicates if the plugin stanza
should be included in the parent
stanza's iterable 'substanzas'
interface results.
stanza -- The class of the parent stanza.
plugin -- The class of the plugin stanza.
iterable -- Indicates if the plugin stanza should be
included in the parent stanza's iterable
'substanzas' interface results.
overrides -- Indicates if the plugin should be allowed
to override the interface handlers for
the parent stanza.
"""
tag = "{%s}%s" % (plugin.namespace, plugin.name)
stanza.plugin_attrib_map[plugin.plugin_attrib] = plugin
stanza.plugin_tag_map[tag] = plugin
if iterable:
# Prevent weird memory reference gotchas.
stanza.plugin_iterables = stanza.plugin_iterables.copy()
stanza.plugin_iterables.add(plugin)
if overrides:
# Prevent weird memory reference gotchas.
stanza.plugin_overrides = stanza.plugin_overrides.copy()
for interface in plugin.overrides:
stanza.plugin_overrides[interface] = plugin.plugin_attrib
# To maintain backwards compatibility for now, preserve the camel case name.
@ -130,6 +138,11 @@ class ElementBase(object):
subitem -- A set of stanza classes which are allowed to
be added as substanzas. Deprecated version
of plugin_iterables.
overrides -- A list of interfaces prepended with 'get_',
'set_', or 'del_'. If the stanza is registered
as a plugin with overrides=True, then the
parent's interface handlers will be
overridden by the plugin's matching handler.
types -- A set of generic type attribute values.
tag -- The namespaced name of the stanza's root
element. Example: "{foo_ns}bar"
@ -139,6 +152,10 @@ class ElementBase(object):
associated plugin stanza classes.
plugin_iterables -- A set of stanza classes which are allowed to
be added as substanzas.
plugin_overrides -- A mapping of interfaces prepended with 'get_',
'set_' or 'del_' to plugin attrib names. Allows
a plugin to override the behaviour of a parent
stanza's interface handlers.
plugin_tag_map -- A mapping of plugin stanza tag names with
the associated plugin stanza classes.
is_extension -- When True, allows the stanza to provide one
@ -204,7 +221,9 @@ class ElementBase(object):
interfaces = set(('type', 'to', 'from', 'id', 'payload'))
types = set(('get', 'set', 'error', None, 'unavailable', 'normal', 'chat'))
sub_interfaces = tuple()
overrides = {}
plugin_attrib_map = {}
plugin_overrides = {}
plugin_iterables = set()
plugin_tag_map = {}
subitem = set()
@ -380,12 +399,13 @@ class ElementBase(object):
The search order for interface value retrieval for an interface
named 'foo' is:
1. The list of substanzas.
2. The result of calling get_foo.
3. The result of calling getFoo.
4. The contents of the foo subelement, if foo is a sub interface.
5. The value of the foo attribute of the XML object.
6. The plugin named 'foo'
7. An empty string.
2. The result of calling the get_foo override handler.
3. The result of calling get_foo.
4. The result of calling getFoo.
5. The contents of the foo subelement, if foo is a sub interface.
6. The value of the foo attribute of the XML object.
7. The plugin named 'foo'
8. An empty string.
Arguments:
attrib -- The name of the requested stanza interface.
@ -395,6 +415,16 @@ class ElementBase(object):
elif attrib in self.interfaces:
get_method = "get_%s" % attrib.lower()
get_method2 = "get%s" % attrib.title()
if self.plugin_overrides:
plugin = self.plugin_overrides.get(get_method, None)
if plugin:
if plugin not in self.plugins:
self.init_plugin(plugin)
handler = getattr(self.plugins[plugin], get_method, None)
if handler:
return handler()
if hasattr(self, get_method):
return getattr(self, get_method)()
elif hasattr(self, get_method2):
@ -429,13 +459,14 @@ class ElementBase(object):
The effect of interface value assignment for an interface
named 'foo' will be one of:
1. Delete the interface's contents if the value is None.
2. Call set_foo, if it exists.
3. Call setFoo, if it exists.
4. Set the text of a foo element, if foo is in sub_interfaces.
5. Set the value of a top level XML attribute name foo.
6. Attempt to pass value to a plugin named foo using the plugin's
2. Call the set_foo override handler, if it exists.
3. Call set_foo, if it exists.
4. Call setFoo, if it exists.
5. Set the text of a foo element, if foo is in sub_interfaces.
6. Set the value of a top level XML attribute name foo.
7. Attempt to pass value to a plugin named foo using the plugin's
foo interface.
7. Do nothing.
8. Do nothing.
Arguments:
attrib -- The name of the stanza interface to modify.
@ -445,6 +476,16 @@ class ElementBase(object):
if value is not None:
set_method = "set_%s" % attrib.lower()
set_method2 = "set%s" % attrib.title()
if self.plugin_overrides:
plugin = self.plugin_overrides.get(set_method, None)
if plugin:
if plugin not in self.plugins:
self.init_plugin(plugin)
handler = getattr(self.plugins[plugin], set_method, None)
if handler:
return handler(value)
if hasattr(self, set_method):
getattr(self, set_method)(value,)
elif hasattr(self, set_method2):
@ -480,12 +521,13 @@ class ElementBase(object):
The effect of deleting a stanza interface value named foo will be
one of:
1. Call del_foo, if it exists.
2. Call delFoo, if it exists.
3. Delete foo element, if foo is in sub_interfaces.
4. Delete top level XML attribute named foo.
5. Remove the foo plugin, if it was loaded.
6. Do nothing.
1. Call del_foo override handler, if it exists.
2. Call del_foo, if it exists.
3. Call delFoo, if it exists.
4. Delete foo element, if foo is in sub_interfaces.
5. Delete top level XML attribute named foo.
6. Remove the foo plugin, if it was loaded.
7. Do nothing.
Arguments:
attrib -- The name of the affected stanza interface.
@ -493,6 +535,16 @@ class ElementBase(object):
if attrib in self.interfaces:
del_method = "del_%s" % attrib.lower()
del_method2 = "del%s" % attrib.title()
if self.plugin_overrides:
plugin = self.plugin_overrides.get(del_method, None)
if plugin:
if plugin not in self.plugins:
self.init_plugin(plugin)
handler = getattr(self.plugins[plugin], del_method, None)
if handler:
return handler()
if hasattr(self, del_method):
getattr(self, del_method)()
elif hasattr(self, del_method2):

97
tests/test_stanza_element.py
View file

@ -53,9 +53,8 @@ class TestElementBase(SleekTest):
name = "foo"
namespace = "foo"
interfaces = set(('bar', 'baz'))
subitem = set((TestSubStanza,))
register_stanza_plugin(TestStanza, TestStanzaPlugin)
register_stanza_plugin(TestStanza, TestStanzaPlugin, iterable=True)
stanza = TestStanza()
stanza['bar'] = 'a'
@ -100,8 +99,8 @@ class TestElementBase(SleekTest):
name = "foo"
namespace = "foo"
interfaces = set(('bar', 'baz'))
subitem = set((TestSubStanza,))
register_stanza_plugin(TestStanza, TestSubStanza, iterable=True)
register_stanza_plugin(TestStanza, TestStanzaPlugin)
register_stanza_plugin(TestStanza, TestStanzaPlugin2)
@ -115,7 +114,7 @@ class TestElementBase(SleekTest):
'substanzas': [{'__childtag__': '{foo}subfoo',
'bar': 'c',
'baz': ''}]}
stanza.setStanzaValues(values)
stanza.values = values
self.check(stanza, """
<foo xmlns="foo" bar="a">
@ -143,7 +142,7 @@ class TestElementBase(SleekTest):
plugin_attrib = "foobar"
interfaces = set(('fizz',))
TestStanza.subitem = (TestStanza,)
register_stanza_plugin(TestStanza, TestStanza, iterable=True)
register_stanza_plugin(TestStanza, TestStanzaPlugin)
stanza = TestStanza()
@ -457,7 +456,6 @@ class TestElementBase(SleekTest):
namespace = "foo"
interfaces = set(('bar','baz', 'qux'))
sub_interfaces = set(('qux',))
subitem = (TestSubStanza,)
def setQux(self, value):
self._set_sub_text('qux', text=value)
@ -470,6 +468,7 @@ class TestElementBase(SleekTest):
namespace = "http://test/slash/bar"
interfaces = set(('attrib',))
register_stanza_plugin(TestStanza, TestSubStanza, iterable=True)
register_stanza_plugin(TestStanza, TestStanzaPlugin)
stanza = TestStanza()
@ -590,7 +589,8 @@ class TestElementBase(SleekTest):
name = "foo"
namespace = "foo"
interfaces = set(('bar', 'baz'))
subitem = (TestSubStanza,)
register_stanza_plugin(TestStanza, TestSubStanza, iterable=True)
stanza = TestStanza()
substanza1 = TestSubStanza()
@ -657,4 +657,87 @@ class TestElementBase(SleekTest):
self.failUnless(stanza1 != stanza2,
"Divergent stanza copies incorrectly compared equal.")
def testExtension(self):
"""Testing using is_extension."""
class TestStanza(ElementBase):
name = "foo"
namespace = "foo"
interfaces = set(('bar', 'baz'))
class TestExtension(ElementBase):
name = 'extended'
namespace = 'foo'
plugin_attrib = name
interfaces = set((name,))
is_extension = True
def set_extended(self, value):
self.xml.text = value
def get_extended(self):
return self.xml.text
def del_extended(self):
self.parent().xml.remove(self.xml)
register_stanza_plugin(TestStanza, TestExtension)
stanza = TestStanza()
stanza['extended'] = 'testing'
self.check(stanza, """
<foo xmlns="foo">
<extended>testing</extended>
</foo>
""")
self.failUnless(stanza['extended'] == 'testing',
"Could not retrieve stanza extension value.")
del stanza['extended']
self.check(stanza, """
<foo xmlns="foo" />
""")
def testOverrides(self):
"""Test using interface overrides."""
class TestStanza(ElementBase):
name = "foo"
namespace = "foo"
interfaces = set(('bar', 'baz'))
class TestOverride(ElementBase):
name = 'overrider'
namespace = 'foo'
plugin_attrib = name
interfaces = set(('bar',))
overrides = ['set_bar']
def setup(self, xml):
# Don't create XML for the plugin
self.xml = ET.Element('')
def set_bar(self, value):
if not value.startswith('override-'):
self.parent()._set_attr('bar', 'override-%s' % value)
else:
self.parent()._set_attr('bar', value)
stanza = TestStanza()
stanza['bar'] = 'foo'
self.check(stanza, """
<foo xmlns="foo" bar="foo" />
""")
register_stanza_plugin(TestStanza, TestOverride, overrides=True)
stanza = TestStanza()
stanza['bar'] = 'foo'
self.check(stanza, """
<foo xmlns="foo" bar="override-foo" />
""")
suite = unittest.TestLoader().loadTestsFromTestCase(TestElementBase)