Begin experiment with a centralized API callback registry.

The API registry generalizes the node handler system from the xep_0030
plugin so that other plugins can use it.

1 files changed, 191 insertions, 0 deletions

diff --git a/sleekxmpp/api.py b/sleekxmpp/api.py
new file mode 100644
index 00000000..9d8ec201
--- /dev/null
+++ b/sleekxmpp/api.py
@@ -0,0 +1,191 @@
+from sleekxmpp.xmlstream import JID
+
+
+class APIWrapper(object):
+
+    def __init__(self, api, name):
+        self.api = api
+        self.name = name
+
+    def __getattr__(self, attr):
+        """Curry API management commands with the API name."""
+        if attr == 'name':
+            return self.name
+        elif attr == 'settings':
+            return self.api.settings[self.name]
+        elif attr == 'register':
+            def curried_handler(handler, op, jid=None, node=None):
+                register = getattr(self.api, attr)
+                return register(handler, self.name, op, jid, node)
+            return curried_handler
+        elif attr == 'register_default':
+            def curried_handler(handler, op, jid=None, node=None):
+                return getattr(self.api, attr)(handler, self.name, op)
+            return curried_handler
+        elif attr in ('run', 'restore_default', 'unregister'):
+            def curried_handler(*args, **kwargs):
+                return getattr(self.api, attr)(self.name, *args, **kwargs)
+            return curried_handler
+        return None
+
+    def __getitem__(self, attr):
+        def curried_handler(jid=None, node=None, ifrom=None, args=None):
+            return self.api.run(self.name, attr, jid, node, ifrom, args)
+        return curried_handler
+
+
+class APIRegistry(object):
+
+    def __init__(self, xmpp):
+        self._handlers = {}
+        self._handler_defaults = {}
+        self.xmpp = xmpp
+        self.settings = {} 
+
+    def _setup(self, ctype, op):
+        """Initialize the API callback dictionaries.
+
+        :param string ctype: The name of the API to initialize.
+        :param string op: The API operation to initialize.
+        """
+        if ctype not in self.settings:
+            self.settings[ctype] = {}
+        if ctype not in self._handler_defaults:
+            self._handler_defaults[ctype] = {}
+        if ctype not in self._handlers:
+            self._handlers[ctype] = {}
+        if op not in self._handlers[ctype]:
+            self._handlers[ctype][op] = {'global': None,
+                                         'jid': {},
+                                         'node': {}}
+
+    def wrap(self, ctype):
+        """Return a wrapper object that targets a specific API."""
+        return APIWrapper(self, ctype)
+
+    def purge(self, ctype):
+        """Remove all information for a given API."""
+        del self.settings[ctype]
+        del self._handler_defaults[ctype]
+        del self._handlers[ctype]
+
+    def run(self, ctype, op, jid=None, node=None, ifrom=None, args=None):
+        """Execute an API callback, based on specificity.
+
+        The API callback that is executed is chosen based on the combination
+        of the provided JID and node:
+
+        JID   | node  | Handler
+        ==============================
+        Given | Given | Node handler
+        Given | None  | JID handler
+        None  | None  | Global handler
+
+        A node handler is responsible for servicing a single node at a single
+        JID, while a JID handler may respond for any node at a given JID, and
+        the global handler will answer to any JID+node combination.
+
+        Handlers should check that the JID ``ifrom`` is authorized to perform
+        the desired action.
+
+        :param string ctype: The name of the API to use.
+        :param string op: The API operation to perform.
+        :param JID jid: Optionally provide specific JID.
+        :param string node: Optionally provide specific node.
+        :param JID ifrom: Optionally provide the requesting JID.
+        :param tuple args: Optional positional arguments to the handler.
+        """
+        self._setup(ctype, op)
+
+        if jid in (None, ''):
+            jid = self.xmpp.boundjid
+        if jid and not isinstance(jid, JID):
+            jid = JID(jid)
+
+        if node is None:
+            node = ''
+
+        if self.xmpp.is_component:
+            if self.settings[ctype].get('component_bare', False):
+                jid = jid.bare
+            else:
+                jid = jid.full
+        else:
+            if self.settings[ctype].get('client_bare', True):
+                jid = jid.bare
+            else:
+                jid = jid.full
+
+        handler = self._handlers[ctype][op]['node'].get((jid, node), None)
+        if handler is None:
+            handler = self._handlers[ctype][op]['jid'].get(jid, None)
+        if handler is None:
+            handler = self._handlers[ctype][op].get('global', None)
+
+        if handler:
+            try:
+                return handler(jid, node, ifrom, args)
+            except TypeError:
+                # To preserve backward compatibility, drop the ifrom
+                # parameter for existing handlers that don't understand it.
+                return handler(jid, node, args)
+
+    def register(self, handler, ctype, op, jid=None, node=None, default=False):
+        """Register an API callback, with JID+node specificity.
+
+        The API callback can later be executed based on the
+        specificity of the provided JID+node combination. 
+        
+        See :meth:`~ApiRegistry.run` for more details.
+
+        :param string ctype: The name of the API to use.
+        :param string op: The API operation to perform.
+        :param JID jid: Optionally provide specific JID.
+        :param string node: Optionally provide specific node.
+        """
+        self._setup(ctype, op)
+        if jid is None and node is None:
+            if handler is None:
+                handler = self._handler_defaults[op]
+            self._handlers[ctype][op]['global'] = handler
+        elif jid is not None and node is None:
+            self._handlers[ctype][op]['jid'][jid] = handler
+        else:
+            self._handlers[ctype][op]['node'][(jid, node)] = handler
+
+    def register_default(self, handler, ctype, op):
+        """Register a default, global handler for an operation.
+
+        :param func handler: The default, global handler for the operation.
+        :param string ctype: The name of the API to modify.
+        :param string op: The API operation to use.
+        """
+        self._setup(ctype, op)
+        self._handler_defaults[ctype][op] = handler
+
+    def unregister(self, ctype, op, jid=None, node=None):
+        """Remove an API callback.
+
+        The API callback chosen for removal is based on the
+        specificity of the provided JID+node combination.
+
+        See :meth:`~ApiRegistry.run` for more details.
+
+        :param string ctype: The name of the API to use.
+        :param string op: The API operation to perform.
+        :param JID jid: Optionally provide specific JID.
+        :param string node: Optionally provide specific node.
+        """
+        self._setup(ctype, op)
+        self.register(None, ctype, op, jid, node)
+
+    def restore_default(self, ctype, op, jid=None, node=None):
+        """Reset an API callback to use a default handler.
+
+        :param string ctype: The name of the API to use.
+        :param string op: The API operation to perform.
+        :param JID jid: Optionally provide specific JID.
+        :param string node: Optionally provide specific node.
+        """
+        self.unregister(ctype, op, jid, node)
+        self.register(self._handler_defaults[ctype][op], ctype, op, jid, node)