plugin schema: PubSub node schema, first draft

node schema is a new SàT Pubsub experimental feature allowing to attach a schema to a node.

src/plugins/plugin_exp_pubsub_schema.py

@@ -0,0 +1,141 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+
+# SAT plugin for Pubsub Schemas
+# Copyright (C) 2009-2017 Jérôme Poisson (goffi@goffi.org)
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from sat.core.i18n import _
+from sat.core import exceptions
+from sat.core.constants import Const as C
+from twisted.words.protocols.jabber import jid
+from twisted.words.protocols.jabber.xmlstream import XMPPHandler
+from sat.core.log import getLogger
+log = getLogger(__name__)
+from wokkel import disco, iwokkel
+from wokkel import data_form
+from wokkel import generic
+from zope.interface import implements
+
+NS_SCHEMA = 'https://salut-a-toi/protocol/schema:0'
+NS_SCHEMA_FORM = 'https://salut-a-toi/protocol/schema#schema:0'
+
+PLUGIN_INFO = {
+    C.PI_NAME: "PubSub Schema",
+    C.PI_IMPORT_NAME: "PUBSUB_SCHEMA",
+    C.PI_TYPE: "EXP",
+    C.PI_PROTOCOLS: [],
+    C.PI_DEPENDENCIES: ["XEP-0060"],
+    C.PI_MAIN: "PubsubSchema",
+    C.PI_HANDLER: "yes",
+    C.PI_DESCRIPTION: _("""Handle Pubsub data schemas""")
+}
+
+
+class PubsubSchema(object):
+
+    def __init__(self, host):
+        log.info(_(u"PubSub Schema initialization"))
+        self.host = host
+        host.bridge.addMethod("psSchemaGet", ".plugin",
+                              in_sign='sss', out_sign='s',
+                              method=self._getSchema,
+                              async=True
+                              )
+        host.bridge.addMethod("psSchemaSet", ".plugin",
+                              in_sign='ssss', out_sign='',
+                              method=self._setSchema,
+                              async=True
+                              )
+
+    def getHandler(self, client):
+        return SchemaHandler()
+
+    def _getSchemaBridgeCb(self, schema_elt):
+        if schema_elt is None:
+            return u''
+        return schema_elt.toXml()
+
+    def _getSchema(self, service, nodeIdentifier, profile_key=C.PROF_KEY_NONE):
+        client = self.host.getClient(profile_key)
+        service = None if not service else jid.JID(service)
+        d = self.getSchema(client, service, nodeIdentifier)
+        d.addCallback(self._getSchemaBridgeCb)
+        return d
+
+    def _getSchemaCb(self, iq_elt):
+        try:
+            schema_elt = next(iq_elt.elements(NS_SCHEMA, 'schema'))
+        except StopIteration:
+            raise exceptions.DataError('missing <schema> element')
+        schema_form = data_form.findForm(schema_elt, NS_SCHEMA_FORM)
+        if schema_form is None:
+            # there is not schema on this node
+            return None
+        # we get again the form because we need all elements/namespaces
+        # while schema_form.toElement while only keep XEP-0004 elements
+        x_elt = next(schema_elt.elements(data_form.NS_X_DATA, 'x'))
+        return x_elt
+
+    def getSchema(self, client, service, nodeIdentifier):
+        """retrieve PubSub node schema
+
+        @param service(jid.JID, None): jid of PubSub service
+            None to use our PEP
+        @param nodeIdentifier(unicode): node to get schema from
+        @return (domish.Element, None): schema (<x> element)
+            None if not schema has been set on this node
+        """
+        iq_elt = client.IQ(u'get')
+        if service is not None:
+            iq_elt['to'] = service.full()
+        pubsub_elt = iq_elt.addElement((NS_SCHEMA, 'pubsub'))
+        schema_elt = pubsub_elt.addElement((NS_SCHEMA, 'schema'))
+        schema_elt['node'] = nodeIdentifier
+        d = iq_elt.send()
+        d.addCallback(self._getSchemaCb)
+        return d
+
+    def _setSchema(self, service, nodeIdentifier, schema, profile_key=C.PROF_KEY_NONE):
+        client = self.host.getClient(profile_key)
+        service = None if not service else jid.JID(service)
+        schema = generic.parseXml(schema.encode('utf-8'))
+        return self.setSchema(client, service, nodeIdentifier, schema)
+
+    def setSchema(self, client, service, nodeIdentifier, schema):
+        """set or replace PubSub node schema
+
+        @param schema(domish.Element, None): schema to set
+            None if schema need to be removed
+        """
+        iq_elt = client.IQ()
+        if service is not None:
+            iq_elt['to'] = service.full()
+        pubsub_elt = iq_elt.addElement((NS_SCHEMA, 'pubsub'))
+        schema_elt = pubsub_elt.addElement((NS_SCHEMA, 'schema'))
+        schema_elt['node'] = nodeIdentifier
+        if schema is not None:
+            schema_elt.addChild(schema)
+        return iq_elt.send()
+
+
+class SchemaHandler(XMPPHandler):
+    implements(iwokkel.IDisco)
+
+    def getDiscoInfo(self, requestor, service, nodeIdentifier=''):
+        return [disco.DiscoFeature(NS_SCHEMA)]
+
+    def getDiscoItems(self, requestor, service, nodeIdentifier=''):
+        return []