plugin XEP-0059: first draft, pubsub and jabber search do not exploit it yet

src/plugins/plugin_xep_0059.py

@@ -0,0 +1,149 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# SAT plugin for Result Set Management (XEP-0059)
+# Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014 Jérôme Poisson (goffi@goffi.org)
+# Copyright (C) 2013, 2014 Adrien Cossa (souliane@mailoo.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.log import getLogger
+log = getLogger(__name__)
+
+from twisted.words.xish import domish
+from wokkel import disco, iwokkel
+try:
+    from twisted.words.protocols.xmlstream import XMPPHandler
+except ImportError:
+    from wokkel.subprotocols import XMPPHandler
+from zope.interface import implements
+
+
+NS_RSM = 'http://jabber.org/protocol/rsm'
+
+PLUGIN_INFO = {
+    "name": "Result Set Management",
+    "import_name": "XEP-0059",
+    "type": "XEP",
+    "protocols": ["XEP-0059"],
+    "main": "XEP_0059",
+    "handler": "no",
+    "description": _("""Implementation of Result Set Management""")
+}
+
+
+class XEP_0059(object):
+
+    def __init__(self, host):
+        log.info(_("Result Set Management plugin initialization"))
+        self.host = host
+
+    def requestPage(self, stanza, limit=10, index=None, after=None, before=None):
+        """Embed a RSM page request in the given stanza.
+
+        @param stanza (domish.Element): any stanza to which RSM applies
+        @param limit (int): the maximum number of items in the page
+        @param index (int): the starting index of the requested page
+        @param after (str, int): the element immediately preceding the page
+        @param before (str, int): the element immediately following the page
+        """
+        main_elt = None
+        try:
+            main_elt = domish.generateElementsNamed(stanza.elements(), name="query").next()
+        except StopIteration:
+            try:
+                main_elt = domish.generateElementsNamed(stanza.elements(), name="pubsub").next()
+            except StopIteration:
+                log.warning("Injection of a RSM element only applies to query or pubsub stanzas")
+                return
+        limit = str(int(limit))
+
+        # in case the service doesn't support RSM, do this at least
+        main_elt.items.attributes['max_items'] = limit
+
+        set_elt = main_elt.addElement('set', NS_RSM)
+        set_elt.addElement('max').addContent(limit)
+        if index:
+            assert(after is None and before is None)
+            set_elt.addElement('index').addContent(str(int(index)))
+        if after:
+            assert(before is None)  # could not specify both at the same time
+            set_elt.addElement('after').addContent(str(after))
+        if before is not None:
+            if before == '':  # request the last page, according to http://xmpp.org/extensions/xep-0059.html#last
+                set_elt.addElement('before')
+            else:
+                set_elt.addElement('before').addContent(str(before))
+
+    def countItems(self, stanza):
+        """Count the items without retrieving any of them.
+
+        @param stanza (domish.Element): any stanza to which RSM applies
+        """
+        self.requestPage(stanza, limit=0)
+
+    def extractMetadata(self, stanza):
+        """Extract the RSM metadata from the given stanza.
+
+        @param stanza (domish.Element, wokkel.pubsub.PubSubRequest):
+           any stanza to which RSM applies. When used by XEP-0060,
+           wokkel's PubSubRequest instance is also accepted.
+        @return: dict containing the page metadata
+        """
+        try:
+            main_elt = domish.generateElementsNamed(stanza.elements(), name="query").next()
+        except StopIteration:
+            try:
+                main_elt = domish.generateElementsNamed(stanza.elements(), name="pubsub").next()
+            except StopIteration:
+                log.warning("Extracting data from a RSM element only applies to query or pubsub stanzas")
+                return {}
+        try:
+            set_elt = domish.generateElementsQNamed(main_elt.elements(), name="set", uri=NS_RSM).next()
+        except StopIteration:
+            log.debug("There's no RSM element in the stanza")
+            return {}
+
+        data = {}
+        elts = set_elt.elements()
+        try:
+            elt = elts.next()
+            if elt.name == "first":
+                data["first"] = "".join(elt.children)
+                data["first_index"] = int(elt.getAttribute("index"))
+            elif elt.name == "last":
+                data["last"] = "".join(elt.children)
+            elif elt.name == "count":
+                data["count"] = int("".join(elt.children))
+        except StopIteration:
+            pass
+        if "count" not in data:
+            log.warning("There's no 'count' element in the RSM element!")
+        return data
+
+
+class XEP_0059_handler(XMPPHandler):
+    implements(iwokkel.IDisco)
+
+    def __init__(self, plugin_parent, profile):
+        self.plugin_parent = plugin_parent
+        self.host = plugin_parent.host
+        self.profile = profile
+
+    def getDiscoInfo(self, requestor, target, nodeIdentifier=''):
+        return [disco.DiscoFeature(NS_RSM)]
+
+    def getDiscoItems(self, requestor, target, nodeIdentifier=''):
+        return []