From 6d45971411f88f134abc28051c678986db8e9df8 Mon Sep 17 00:00:00 2001 From: Lance Stout Date: Thu, 24 Mar 2011 12:25:17 -0400 Subject: Allow a stanza plugin to override a parent's interfaces. 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' --- sleekxmpp/xmlstream/stanzabase.py | 102 ++++++++++++++++++++++++++++---------- 1 file changed, 77 insertions(+), 25 deletions(-) (limited to 'sleekxmpp/xmlstream/stanzabase.py') diff --git a/sleekxmpp/xmlstream/stanzabase.py b/sleekxmpp/xmlstream/stanzabase.py index 860f8d13..b8a7ceaa 100644 --- a/sleekxmpp/xmlstream/stanzabase.py +++ b/sleekxmpp/xmlstream/stanzabase.py @@ -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): -- cgit v1.2.3