--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libervia/backend/plugins/plugin_xep_0231.py	Fri Jun 02 11:49:51 2023 +0200
@@ -0,0 +1,250 @@
+#!/usr/bin/env python3
+
+
+# SAT plugin for Bit of Binary handling (XEP-0231)
+# Copyright (C) 2009-2021 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/>.
+
+import base64
+import time
+from pathlib import Path
+from functools import partial
+from zope.interface import implementer
+from twisted.python import failure
+from twisted.words.protocols.jabber import xmlstream
+from twisted.words.protocols.jabber import jid
+from twisted.words.protocols.jabber import error as jabber_error
+from twisted.internet import defer
+from wokkel import disco, iwokkel
+from libervia.backend.tools import xml_tools
+from libervia.backend.core.i18n import _
+from libervia.backend.core.constants import Const as C
+from libervia.backend.core import exceptions
+from libervia.backend.core.log import getLogger
+
+log = getLogger(__name__)
+
+
+PLUGIN_INFO = {
+    C.PI_NAME: "Bits of Binary",
+    C.PI_IMPORT_NAME: "XEP-0231",
+    C.PI_TYPE: "XEP",
+    C.PI_MODES: C.PLUG_MODE_BOTH,
+    C.PI_PROTOCOLS: ["XEP-0231"],
+    C.PI_MAIN: "XEP_0231",
+    C.PI_HANDLER: "yes",
+    C.PI_DESCRIPTION: _(
+        """Implementation of bits of binary (used for small images/files)"""
+    ),
+}
+
+NS_BOB = "urn:xmpp:bob"
+IQ_BOB_REQUEST = C.IQ_GET + '/data[@xmlns="' + NS_BOB + '"]'
+
+
+class XEP_0231(object):
+    def __init__(self, host):
+        log.info(_("plugin Bits of Binary initialization"))
+        self.host = host
+        host.register_namespace("bob", NS_BOB)
+        host.trigger.add("xhtml_post_treat", self.xhtml_trigger)
+        host.bridge.add_method(
+            "bob_get_file",
+            ".plugin",
+            in_sign="sss",
+            out_sign="s",
+            method=self._get_file,
+            async_=True,
+        )
+
+    def dump_data(self, cache, data_elt, cid):
+        """save file encoded in data_elt to cache
+
+        @param cache(memory.cache.Cache): cache to use to store the data
+        @param data_elt(domish.Element): <data> as in XEP-0231
+        @param cid(unicode): content-id
+        @return(unicode): full path to dumped file
+        """
+        #  FIXME: is it needed to use a separate thread?
+        #        probably not with the little data expected with BoB
+        try:
+            max_age = int(data_elt["max-age"])
+            if max_age < 0:
+                raise ValueError
+        except (KeyError, ValueError):
+            log.warning("invalid max-age found")
+            max_age = None
+
+        with cache.cache_data(
+            PLUGIN_INFO[C.PI_IMPORT_NAME], cid, data_elt.getAttribute("type"), max_age
+        ) as f:
+
+            file_path = Path(f.name)
+            f.write(base64.b64decode(str(data_elt)))
+
+        return file_path
+
+    def get_handler(self, client):
+        return XEP_0231_handler(self)
+
+    def _request_cb(self, iq_elt, cache, cid):
+        for data_elt in iq_elt.elements(NS_BOB, "data"):
+            if data_elt.getAttribute("cid") == cid:
+                file_path = self.dump_data(cache, data_elt, cid)
+                return file_path
+
+        log.warning(
+            "invalid data stanza received, requested cid was not found:\n{iq_elt}\nrequested cid: {cid}".format(
+                iq_elt=iq_elt, cid=cid
+            )
+        )
+        raise failure.Failure(exceptions.DataError("missing data"))
+
+    def _request_eb(self, failure_):
+        """Log the error and continue errback chain"""
+        log.warning("Can't get requested data:\n{reason}".format(reason=failure_))
+        return failure_
+
+    def request_data(self, client, to_jid, cid, cache=None):
+        """Request data if we don't have it in cache
+
+        @param to_jid(jid.JID): jid to request the data to
+        @param cid(unicode): content id
+        @param cache(memory.cache.Cache, None): cache to use
+            client.cache will be used if None
+        @return D(unicode): path to file with data
+        """
+        if cache is None:
+            cache = client.cache
+        iq_elt = client.IQ("get")
+        iq_elt["to"] = to_jid.full()
+        data_elt = iq_elt.addElement((NS_BOB, "data"))
+        data_elt["cid"] = cid
+        d = iq_elt.send()
+        d.addCallback(self._request_cb, cache, cid)
+        d.addErrback(self._request_eb)
+        return d
+
+    def _set_img_elt_src(self, path, img_elt):
+        img_elt["src"] = "file://{}".format(path)
+
+    def xhtml_trigger(self, client, message_elt, body_elt, lang, treat_d):
+        for img_elt in xml_tools.find_all(body_elt, C.NS_XHTML, "img"):
+            source = img_elt.getAttribute("src", "")
+            if source.startswith("cid:"):
+                cid = source[4:]
+                file_path = client.cache.get_file_path(cid)
+                if file_path is not None:
+                    #  image is in cache, we change the url
+                    img_elt["src"] = "file://{}".format(file_path)
+                    continue
+                else:
+                    # image is not in cache, is it given locally?
+                    for data_elt in message_elt.elements(NS_BOB, "data"):
+                        if data_elt.getAttribute("cid") == cid:
+                            file_path = self.dump_data(client.cache, data_elt, cid)
+                            img_elt["src"] = "file://{}".format(file_path)
+                            break
+                    else:
+                        # cid not found locally, we need to request it
+                        # so we use the deferred
+                        d = self.request_data(client, jid.JID(message_elt["from"]), cid)
+                        d.addCallback(partial(self._set_img_elt_src, img_elt=img_elt))
+                        treat_d.addCallback(lambda __: d)
+
+    def on_component_request(self, iq_elt, client):
+        """cache data is retrieve from common cache for components"""
+        # FIXME: this is a security/privacy issue as no access check is done
+        #        but this is mitigated by the fact that the cid must be known.
+        #        An access check should be implemented though.
+
+        iq_elt.handled = True
+        data_elt = next(iq_elt.elements(NS_BOB, "data"))
+        try:
+            cid = data_elt["cid"]
+        except KeyError:
+            error_elt = jabber_error.StanzaError("not-acceptable").toResponse(iq_elt)
+            client.send(error_elt)
+            return
+
+        metadata = self.host.common_cache.get_metadata(cid)
+        if metadata is None:
+            error_elt = jabber_error.StanzaError("item-not-found").toResponse(iq_elt)
+            client.send(error_elt)
+            return
+
+        with open(metadata["path"], 'rb') as f:
+            data = f.read()
+
+        result_elt = xmlstream.toResponse(iq_elt, "result")
+        data_elt = result_elt.addElement(
+            (NS_BOB, "data"), content=base64.b64encode(data).decode())
+        data_elt["cid"] = cid
+        data_elt["type"] = metadata["mime_type"]
+        data_elt["max-age"] = str(int(max(0, metadata["eol"] - time.time())))
+        client.send(result_elt)
+
+    def _get_file(self, peer_jid_s, cid, profile):
+        peer_jid = jid.JID(peer_jid_s)
+        assert cid
+        client = self.host.get_client(profile)
+        d = self.get_file(client, peer_jid, cid)
+        d.addCallback(lambda path: str(path))
+        return d
+
+    def get_file(self, client, peer_jid, cid, parent_elt=None):
+        """Retrieve a file from it's content-id
+
+        @param peer_jid(jid.JID): jid of the entity offering the data
+        @param cid(unicode): content-id of file data
+        @param parent_elt(domish.Element, None): if file is not in cache,
+            data will be looked after in children of this elements.
+            None to ignore
+        @return D(Path): path to cached data
+        """
+        file_path = client.cache.get_file_path(cid)
+        if file_path is not None:
+            #  file is in cache
+            return defer.succeed(file_path)
+        else:
+            # file not in cache, is it given locally?
+            if parent_elt is not None:
+                for data_elt in parent_elt.elements(NS_BOB, "data"):
+                    if data_elt.getAttribute("cid") == cid:
+                        return defer.succeed(self.dump_data(client.cache, data_elt, cid))
+
+            # cid not found locally, we need to request it
+            # so we use the deferred
+            return self.request_data(client, peer_jid, cid)
+
+
+@implementer(iwokkel.IDisco)
+class XEP_0231_handler(xmlstream.XMPPHandler):
+
+    def __init__(self, plugin_parent):
+        self.plugin_parent = plugin_parent
+        self.host = plugin_parent.host
+
+    def connectionInitialized(self):
+        if self.parent.is_component:
+            self.xmlstream.addObserver(
+                IQ_BOB_REQUEST, self.plugin_parent.on_component_request, client=self.parent
+            )
+
+    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
+        return [disco.DiscoFeature(NS_BOB)]
+
+    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
+        return []