diff --git a/sat/plugins/plugin_blog_import.py b/sat/plugins/plugin_blog_import.py
index c61b8694..29220aac 100644
--- a/sat/plugins/plugin_blog_import.py
+++ b/sat/plugins/plugin_blog_import.py
@@ -307,7 +307,7 @@ class BlogImportPlugin(object):
                     "%", "_"
                 )  # FIXME: tmp workaround for a bug in prosody http upload
                 __, download_d = yield self._u.upload(
-                    client, tmp_file, filename, options=upload_options
+                    client, tmp_file, filename, extra=upload_options
                 )
                 download_url = yield download_d
             except Exception as e:
diff --git a/sat/plugins/plugin_misc_attach.py b/sat/plugins/plugin_misc_attach.py
index 2c4d8b17..73bd4037 100644
--- a/sat/plugins/plugin_misc_attach.py
+++ b/sat/plugins/plugin_misc_attach.py
@@ -16,15 +16,19 @@
 # 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 pathlib import Path
 from collections import namedtuple
-from twisted.internet import defer
 import mimetypes
-import tempfile
+from pathlib import Path
 import shutil
-from sat.core.i18n import _
+import tempfile
+from typing import Callable, Optional
+
+from twisted.internet import defer
+
 from sat.core import exceptions
 from sat.core.constants import Const as C
+from sat.core.core_types import SatXMPPEntity
+from sat.core.i18n import _
 from sat.core.log import getLogger
 from sat.tools import utils
 from sat.tools import image
@@ -37,6 +41,7 @@ PLUGIN_INFO = {
     C.PI_NAME: "File Attach",
     C.PI_IMPORT_NAME: "ATTACH",
     C.PI_TYPE: C.PLUG_TYPE_MISC,
+    C.PI_MODES: C.PLUG_MODE_BOTH,
     C.PI_DEPENDENCIES: ["UPLOAD"],
     C.PI_MAIN: "AttachPlugin",
     C.PI_HANDLER: "no",
@@ -152,7 +157,12 @@ class AttachPlugin:
 
         return data
 
-    async def uploadFiles(self, client, data, upload_cb=None):
+    async def upload_files(
+        self,
+        client: SatXMPPEntity,
+        data: dict,
+        upload_cb: Optional[Callable] = None
+    ):
         """Upload file, and update attachments
 
         invalid attachments will be removed
@@ -160,7 +170,7 @@ class AttachPlugin:
         @param data(dict): message data
         @param upload_cb(coroutine, Deferred, None): method to use for upload
             if None, upload method from UPLOAD plugin will be used.
-            Otherwise, following kwargs will be use with the cb:
+            Otherwise, following kwargs will be used with the cb:
                 - client
                 - filepath
                 - filename
@@ -179,7 +189,7 @@ class AttachPlugin:
 
         for attachment in attachments:
             try:
-                # we pop path because we don't want it to be stored, as the image can be
+                # we pop path because we don't want it to be stored, as the file can be
                 # only in a temporary location
                 path = Path(attachment.pop("path"))
             except KeyError:
@@ -198,14 +208,18 @@ class AttachPlugin:
             except KeyError:
                 name = attachment["name"] = path.name
 
-            options = {}
+            attachment["size"] = path.stat().st_size
+
+            extra = {
+                "attachment": attachment
+            }
             progress_id = attachment.pop("progress_id", None)
             if progress_id:
-                options["progress_id"] = progress_id
+                extra["progress_id"] = progress_id
             check_certificate = self.host.memory.getParamA(
                 "check_certificate", "Connection", profile_key=client.profile)
             if not check_certificate:
-                options['ignore_tls_errors'] = True
+                extra['ignore_tls_errors'] = True
                 log.warning(
                     _("certificate check disabled for upload, this is dangerous!"))
 
@@ -213,7 +227,7 @@ class AttachPlugin:
                 client=client,
                 filepath=path,
                 filename=name,
-                options=options,
+                extra=extra,
             )
             uploads_d.append(upload_d)
 
@@ -246,9 +260,11 @@ class AttachPlugin:
         return True
 
     async def defaultAttach(self, client, data):
-        await self.uploadFiles(client, data)
+        await self.upload_files(client, data)
         # TODO: handle xhtml-im
-        body_elt = next(data["xml"].elements(C.NS_CLIENT, "body"))
+        body_elt = data["xml"].body
+        if body_elt is None:
+            body_elt = data["xml"].addElement("body")
         attachments = data["extra"][C.MESS_KEY_ATTACHMENTS]
         if attachments:
             body_links = '\n'.join(a['url'] for a in attachments)
diff --git a/sat/plugins/plugin_misc_download.py b/sat/plugins/plugin_misc_download.py
index 7a76e5d2..e30fd923 100644
--- a/sat/plugins/plugin_misc_download.py
+++ b/sat/plugins/plugin_misc_download.py
@@ -16,19 +16,23 @@
 # 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 pathlib import Path
-from urllib.parse import urlparse, unquote
 import hashlib
+from pathlib import Path
+from typing import Any, Dict, Optional, Union, Tuple, Callable
+from urllib.parse import unquote, urlparse
+
 import treq
 from twisted.internet import defer
 from twisted.words.protocols.jabber import error as jabber_error
-from sat.core.i18n import _, D_
-from sat.core.constants import Const as C
-from sat.core.log import getLogger
+
 from sat.core import exceptions
+from sat.core.constants import Const as C
+from sat.core.core_types import SatXMPPEntity
+from sat.core.i18n import D_, _
+from sat.core.log import getLogger
 from sat.tools import xml_tools
-from sat.tools.common import data_format
 from sat.tools import stream
+from sat.tools.common import data_format
 from sat.tools.web import treq_client_no_ssl
 
 log = getLogger(__name__)
@@ -38,6 +42,7 @@ PLUGIN_INFO = {
     C.PI_NAME: "File Download",
     C.PI_IMPORT_NAME: "DOWNLOAD",
     C.PI_TYPE: C.PLUG_TYPE_MISC,
+    C.PI_MODES: C.PLUG_MODE_BOTH,
     C.PI_MAIN: "DownloadPlugin",
     C.PI_HANDLER: "no",
     C.PI_DESCRIPTION: _("""File download management"""),
@@ -53,7 +58,7 @@ class DownloadPlugin(object):
             "fileDownload",
             ".plugin",
             in_sign="ssss",
-            out_sign="a{ss}",
+            out_sign="s",
             method=self._fileDownload,
             async_=True,
         )
@@ -66,18 +71,29 @@ class DownloadPlugin(object):
             async_=True,
         )
         self._download_callbacks = {}
-        self.registerScheme('http', self.downloadHTTP)
-        self.registerScheme('https', self.downloadHTTP)
+        self._scheme_callbacks = {}
+        self.register_scheme('http', self.download_http)
+        self.register_scheme('https', self.download_http)
 
-    def _fileDownload(self, uri, dest_path, options_s, profile):
-        client = self.host.getClient(profile)
-        options = data_format.deserialise(options_s)
-
-        return defer.ensureDeferred(self.fileDownload(
-            client, uri, Path(dest_path), options
+    def _fileDownload(
+            self, attachment_s: str, dest_path: str, extra_s: str, profile: str
+    ) -> defer.Deferred:
+        d = defer.ensureDeferred(self.file_download(
+            self.host.getClient(profile),
+            data_format.deserialise(attachment_s),
+            Path(dest_path),
+            data_format.deserialise(extra_s)
         ))
+        d.addCallback(lambda ret: data_format.serialise(ret))
+        return d
 
-    async def fileDownload(self, client, uri, dest_path, options=None):
+    async def file_download(
+        self,
+        client: SatXMPPEntity,
+        attachment: Dict[str, Any],
+        dest_path: Path,
+        extra: Optional[Dict[str, Any]] = None
+    ) -> Dict[str, Any]:
         """Download a file using best available method
 
         parameters are the same as for [download]
@@ -85,7 +101,7 @@ class DownloadPlugin(object):
             message
         """
         try:
-            progress_id, __ = await self.download(client, uri, dest_path, options)
+            progress_id, __ = await self.download(client, attachment, dest_path, extra)
         except Exception as e:
             if (isinstance(e, jabber_error.StanzaError)
                 and e.condition == 'not-acceptable'):
@@ -102,45 +118,44 @@ class DownloadPlugin(object):
         else:
             return {"progress": progress_id}
 
-    def _fileDownloadComplete(self, uri, dest_path, options_s, profile):
-        client = self.host.getClient(profile)
-        options = data_format.deserialise(options_s)
-
-        d = defer.ensureDeferred(self.fileDownloadComplete(
-            client, uri, dest_path, options
+    def _fileDownloadComplete(
+            self, attachment_s: str, dest_path: str, extra_s: str, profile: str
+    ) -> defer.Deferred:
+        d = defer.ensureDeferred(self.file_download_complete(
+            self.host.getClient(profile),
+            data_format.deserialise(attachment_s),
+            Path(dest_path),
+            data_format.deserialise(extra_s)
         ))
         d.addCallback(lambda path: str(path))
         return d
 
-    async def fileDownloadComplete(self, client, uri, dest_path, options=None):
+    async def file_download_complete(
+        self,
+        client: SatXMPPEntity,
+        attachment: Dict[str, Any],
+        dest_path: Path,
+        extra: Optional[Dict[str, Any]] = None
+    ) -> str:
         """Helper method to fully download a file and return its path
 
         parameters are the same as for [download]
         @return (str): path to the downloaded file
             use empty string to store the file in cache
         """
-        __, download_d = await self.download(client, uri, dest_path, options)
+        __, download_d = await self.download(client, attachment, dest_path, extra)
         dest_path = await download_d
         return dest_path
 
-    async def download(self, client, uri, dest_path, options=None):
-        """Send a file using best available method
-
-        @param uri(str): URI to the file to download
-        @param dest_path(str, Path): where the file must be downloaded
-            if empty string, the file will be stored in local path
-        @param options(dict, None): options depending on scheme handler
-            Some common options:
-                - ignore_tls_errors(bool): True to ignore SSL/TLS certificate verification
-                  used only if HTTPS transport is needed
-        @return (tuple[unicode,D(unicode)]): progress_id and a Deferred which fire
-            download URL when download is finished
-            progress_id can be empty string if the file already exist and is not
-            downloaded again (can happen if cache is used with empty dest_path)
-        """
-        if options is None:
-            options = {}
-
+    async def download_uri(
+        self,
+        client: SatXMPPEntity,
+        uri: str,
+        dest_path: Union[Path, str],
+        extra: Optional[Dict[str, Any]] = None
+    ) -> Tuple[str, defer.Deferred]:
+        if extra is None:
+            extra = {}
         uri_parsed = urlparse(uri, 'http')
         if dest_path:
             dest_path = Path(dest_path)
@@ -171,18 +186,18 @@ class DownloadPlugin(object):
         check_certificate = self.host.memory.getParamA(
             "check_certificate", "Connection", profile_key=client.profile)
         if not check_certificate:
-            options['ignore_tls_errors'] = True
+            extra['ignore_tls_errors'] = True
             log.warning(
                 _("certificate check disabled for download, this is dangerous!"))
 
         try:
-            callback = self._download_callbacks[uri_parsed.scheme]
+            callback = self._scheme_callbacks[uri_parsed.scheme]
         except KeyError:
             raise exceptions.NotFound(f"Can't find any handler for uri {uri}")
         else:
             try:
                 progress_id, download_d = await callback(
-                    client, uri_parsed, dest_path, options)
+                    client, uri_parsed, dest_path, extra)
             except Exception as e:
                 log.warning(_(
                     "Can't download URI {uri}: {reason}").format(
@@ -195,11 +210,96 @@ class DownloadPlugin(object):
             download_d.addCallback(lambda __: dest_path)
             return progress_id, download_d
 
-    def registerScheme(self, scheme, download_cb):
+
+    async def download(
+        self,
+        client: SatXMPPEntity,
+        attachment: Dict[str, Any],
+        dest_path: Union[Path, str],
+        extra: Optional[Dict[str, Any]] = None
+    ) -> Tuple[str, defer.Deferred]:
+        """Download a file from URI using suitable method
+
+        @param uri: URI to the file to download
+        @param dest_path: where the file must be downloaded
+            if empty string, the file will be stored in local path
+        @param extra: options depending on scheme handler
+            Some common options:
+                - ignore_tls_errors(bool): True to ignore SSL/TLS certificate verification
+                  used only if HTTPS transport is needed
+        @return: ``progress_id`` and a Deferred which fire download URL when download is
+            finished.
+            ``progress_id`` can be empty string if the file already exist and is not
+            downloaded again (can happen if cache is used with empty ``dest_path``).
+        """
+        uri = attachment.get("uri")
+        if uri:
+            return await self.download_uri(client, uri, dest_path, extra)
+        else:
+            for source in attachment.get("sources", []):
+                source_type = source.get("type")
+                if not source_type:
+                    log.warning(
+                        "source type is missing for source: {source}\nattachment: "
+                        f"{attachment}"
+                    )
+                    continue
+                try:
+                    cb = self._download_callbacks[source_type]
+                except KeyError:
+                    log.warning(
+                        f"no source handler registered for {source_type!r}"
+                    )
+                else:
+                    try:
+                        return await cb(client, attachment, source, dest_path, extra)
+                    except exceptions.CancelError as e:
+                        # the handler can't or doesn't want to handle this source
+                        log.debug(
+                            f"Following source handling by {cb} has been cancelled ({e}):"
+                            f"{source}"
+                        )
+
+        log.warning(
+            "no source could be handled, we can't download the attachment:\n"
+            f"{attachment}"
+        )
+        raise exceptions.FeatureNotFound("no handler could manage the attachment")
+
+    def register_download_handler(
+        self,
+        source_type: str,
+        callback: Callable[
+            [
+                SatXMPPEntity, Dict[str, Any], Dict[str, Any], Union[str, Path],
+                Dict[str, Any]
+            ],
+            Tuple[str, defer.Deferred]
+        ]
+    ) -> None:
+        """Register a handler to manage a type of attachment source
+
+        @param source_type: ``type`` of source handled
+            This is usually the namespace of the protocol used
+        @param callback: method to call to manage the source.
+            Call arguments are the same as for [download], with an extra ``source`` dict
+            which is used just after ``attachment`` to give a quick reference to the
+            source used.
+            The callabke must return a tuple with:
+                - progress ID
+                - a Deferred which fire whant the file is fully downloaded
+        """
+        if source_type is self._download_callbacks:
+            raise exceptions.ConflictError(
+                f"The is already a callback registered for source type {source_type!r}"
+            )
+        self._download_callbacks[source_type] = callback
+
+    def register_scheme(self, scheme: str, download_cb: Callable) -> None:
         """Register an URI scheme handler
 
-        @param scheme(unicode): URI scheme this callback is handling
-        @param download_cb(callable): callback to download a file
+        @param scheme: URI scheme this callback is handling
+        @param download_cb: callback to download a file
             arguments are:
                 - (SatXMPPClient) client
                 - (urllib.parse.SplitResult) parsed URI
@@ -208,19 +308,19 @@ class DownloadPlugin(object):
             must return a tuple with progress_id and a Deferred which fire when download
             is finished
         """
-        if scheme in self._download_callbacks:
+        if scheme in self._scheme_callbacks:
             raise exceptions.ConflictError(
                 f"A method with scheme {scheme!r} is already registered"
             )
-        self._download_callbacks[scheme] = download_cb
+        self._scheme_callbacks[scheme] = download_cb
 
     def unregister(self, scheme):
         try:
-            del self._download_callbacks[scheme]
+            del self._scheme_callbacks[scheme]
         except KeyError:
             raise exceptions.NotFound(f"No callback registered for scheme {scheme!r}")
 
-    def errbackDownload(self, file_obj, download_d, resp):
+    def errback_download(self, file_obj, download_d, resp):
         """Set file_obj and download deferred appropriatly after a network error
 
         @param file_obj(SatFile): file where the download must be done
@@ -231,7 +331,7 @@ class DownloadPlugin(object):
         file_obj.close(error=msg)
         download_d.errback(exceptions.NetworkError(msg))
 
-    async def downloadHTTP(self, client, uri_parsed, dest_path, options):
+    async def download_http(self, client, uri_parsed, dest_path, options):
         url = uri_parsed.geturl()
 
         if options.get('ignore_tls_errors', False):
@@ -264,5 +364,5 @@ class DownloadPlugin(object):
             d.addBoth(lambda _: file_obj.close())
         else:
             d = defer.Deferred()
-            self.errbackDownload(file_obj, d, resp)
+            self.errback_download(file_obj, d, resp)
         return progress_id, d
diff --git a/sat/plugins/plugin_misc_upload.py b/sat/plugins/plugin_misc_upload.py
index 86b8b4e4..5b82bc7a 100644
--- a/sat/plugins/plugin_misc_upload.py
+++ b/sat/plugins/plugin_misc_upload.py
@@ -18,15 +18,20 @@
 
 import os
 import os.path
+from pathlib import Path
+from typing import Optional, Tuple, Union
+
 from twisted.internet import defer
 from twisted.words.protocols.jabber import jid
 from twisted.words.protocols.jabber import error as jabber_error
-from sat.core.i18n import _, D_
-from sat.core.constants import Const as C
-from sat.tools.common import data_format
-from sat.core.log import getLogger
+
 from sat.core import exceptions
+from sat.core.constants import Const as C
+from sat.core.core_types import SatXMPPEntity
+from sat.core.i18n import D_, _
+from sat.core.log import getLogger
 from sat.tools import xml_tools
+from sat.tools.common import data_format
 
 log = getLogger(__name__)
 
@@ -99,26 +104,32 @@ class UploadPlugin(object):
         else:
             return {"progress": progress_id}
 
-    async def upload(self, client, filepath, filename=None, upload_jid=None,
-                     options=None):
+    async def upload(
+        self,
+        client: SatXMPPEntity,
+        filepath: Union[Path, str],
+        filename: Optional[str] = None,
+        upload_jid: Optional[jid.JID] = None,
+        extra: Optional[dict]=None
+    ) -> Tuple[str, defer.Deferred]:
         """Send a file using best available method
 
-        @param filepath(str): absolute path to the file
-        @param filename(None, unicode): name to use for the upload
+        @param filepath: absolute path to the file
+        @param filename: name to use for the upload
             None to use basename of the path
-        @param upload_jid(jid.JID, None): upload capable entity jid,
+        @param upload_jid: upload capable entity jid,
             or None to use autodetected, if possible
-        @param options(dict): option to use for the upload, may be:
+        @param extra: extra data/options to use for the upload, may be:
             - ignore_tls_errors(bool): True to ignore SSL/TLS certificate verification
                 used only if HTTPS transport is needed
             - progress_id(str): id to use for progression
                 if not specified, one will be generated
         @param profile: %(doc_profile)s
-        @return (tuple[unicode,D(unicode)]): progress_id and a Deferred which fire
-            download URL when upload is finished
+        @return: progress_id and a Deferred which fire download URL when upload is
+            finished
         """
-        if options is None:
-            options = {}
+        if extra is None:
+            extra = {}
         if not os.path.isfile(filepath):
             raise exceptions.DataError("The given path doesn't link to a file")
         for method_name, available_cb, upload_cb, priority in self._upload_callbacks:
@@ -132,7 +143,7 @@ class UploadPlugin(object):
                 "{name} method will be used to upload the file".format(name=method_name)
             )
             progress_id, download_d = await upload_cb(
-                client, filepath, filename, upload_jid, options
+                client, filepath, filename, upload_jid, extra
             )
             return progress_id, download_d
 
diff --git a/sat/plugins/plugin_sec_aesgcm.py b/sat/plugins/plugin_sec_aesgcm.py
index 6b1b5233..76a75b3c 100644
--- a/sat/plugins/plugin_sec_aesgcm.py
+++ b/sat/plugins/plugin_sec_aesgcm.py
@@ -63,13 +63,13 @@ class AESGCM(object):
         log.info(_("AESGCM plugin initialization"))
         self._http_upload = host.plugins['XEP-0363']
         self._attach = host.plugins["ATTACH"]
-        host.plugins["DOWNLOAD"].registerScheme(
+        host.plugins["DOWNLOAD"].register_scheme(
             "aesgcm", self.download
         )
         self._attach.register(
             self.canHandleAttachment, self.attach, encrypted=True)
-        host.trigger.add("XEP-0363_upload_size", self._uploadSizeTrigger)
-        host.trigger.add("XEP-0363_upload", self._uploadTrigger)
+        host.trigger.add("XEP-0363_upload_pre_slot", self._upload_pre_slot)
+        host.trigger.add("XEP-0363_upload", self._upload_trigger)
         host.trigger.add("messageReceived", self._messageReceivedTrigger)
 
     async def download(self, client, uri_parsed, dest_path, options):
@@ -129,7 +129,7 @@ class AESGCM(object):
                 decryptor=decryptor))
         else:
             d = defer.Deferred()
-            self.host.plugins["DOWNLOAD"].errbackDownload(file_obj, d, resp)
+            self.host.plugins["DOWNLOAD"].errback_download(file_obj, d, resp)
         return progress_id, d
 
     async def canHandleAttachment(self, client, data):
@@ -140,13 +140,13 @@ class AESGCM(object):
         else:
             return True
 
-    async def _uploadCb(self, client, filepath, filename, options):
-        options['encryption'] = C.ENC_AES_GCM
-        return await self._http_upload.fileHTTPUpload(
+    async def _upload_cb(self, client, filepath, filename, extra):
+        extra['encryption'] = C.ENC_AES_GCM
+        return await self._http_upload.file_http_upload(
             client=client,
             filepath=filepath,
             filename=filename,
-            options=options
+            extra=extra
         )
 
     async def attach(self, client, data):
@@ -160,14 +160,16 @@ class AESGCM(object):
         if not data['message'] or data['message'] == {'': ''}:
             extra_attachments = attachments[1:]
             del attachments[1:]
-            await self._attach.uploadFiles(client, data, upload_cb=self._uploadCb)
+            await self._attach.upload_files(client, data, upload_cb=self._upload_cb)
         else:
             # we have a message, we must send first attachment separately
             extra_attachments = attachments[:]
             attachments.clear()
             del data["extra"][C.MESS_KEY_ATTACHMENTS]
 
-        body_elt = next(data["xml"].elements(C.NS_CLIENT, "body"))
+        body_elt = data["xml"].body
+        if body_elt is None:
+            body_elt = data["xml"].addElement("body")
 
         for attachment in attachments:
             body_elt.addContent(attachment["url"])
@@ -219,11 +221,11 @@ class AESGCM(object):
             decrypted = decryptor.update(data)
             file_obj.write(decrypted)
 
-    def _uploadSizeTrigger(self, client, options, file_path, size, size_adjust):
-        if options.get('encryption') != C.ENC_AES_GCM:
+    def _upload_pre_slot(self, client, extra, file_metadata):
+        if extra.get('encryption') != C.ENC_AES_GCM:
             return True
         # the tag is appended to the file
-        size_adjust.append(16)
+        file_metadata["size"] += 16
         return True
 
     def _encrypt(self, data, encryptor):
@@ -239,8 +241,8 @@ class AESGCM(object):
                 # as we have already finalized, we can now send EOF
                 return b''
 
-    def _uploadTrigger(self, client, options, sat_file, file_producer, slot):
-        if options.get('encryption') != C.ENC_AES_GCM:
+    def _upload_trigger(self, client, extra, sat_file, file_producer, slot):
+        if extra.get('encryption') != C.ENC_AES_GCM:
             return True
         log.debug("encrypting file with AES-GCM")
         iv = secrets.token_bytes(12)
@@ -255,7 +257,7 @@ class AESGCM(object):
         # so we need to check with final data length to avoid a warning on close()
         sat_file.check_size_with_read = True
 
-        # file_producer get length directly from file, and this cause trouble has
+        # file_producer get length directly from file, and this cause trouble as
         # we have to change the size because of encryption. So we adapt it here,
         # else the producer would stop reading prematurely
         file_producer.length = sat_file.size
diff --git a/sat/plugins/plugin_xep_0363.py b/sat/plugins/plugin_xep_0363.py
index e4c4388e..ff7b6929 100644
--- a/sat/plugins/plugin_xep_0363.py
+++ b/sat/plugins/plugin_xep_0363.py
@@ -16,25 +16,29 @@
 # 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 os.path
-import mimetypes
-from typing import NamedTuple, Callable, Optional
 from dataclasses import dataclass
+import mimetypes
+import os.path
+from pathlib import Path
+from typing import Callable, NamedTuple, Optional, Tuple
 from urllib import parse
-from wokkel import disco, iwokkel
-from zope.interface import implementer
-from twisted.words.protocols.jabber import jid, xmlstream, error
-from twisted.words.xish import domish
+
 from twisted.internet import reactor
 from twisted.internet import defer
 from twisted.web import client as http_client
 from twisted.web import http_headers
-from sat.core.i18n import _
-from sat.core.xmpp import SatXMPPComponent
-from sat.core.constants import Const as C
-from sat.core.log import getLogger
+from twisted.words.protocols.jabber import error, jid, xmlstream
+from twisted.words.xish import domish
+from wokkel import disco, iwokkel
+from zope.interface import implementer
+
 from sat.core import exceptions
-from sat.tools import web as sat_web, utils
+from sat.core.constants import Const as C
+from sat.core.core_types import SatXMPPEntity
+from sat.core.i18n import _
+from sat.core.log import getLogger
+from sat.core.xmpp import SatXMPPComponent
+from sat.tools import utils, web as sat_web
 
 
 log = getLogger(__name__)
@@ -87,7 +91,7 @@ class XEP_0363:
             ".plugin",
             in_sign="sssbs",
             out_sign="",
-            method=self._fileHTTPUpload,
+            method=self._file_http_upload,
         )
         host.bridge.addMethod(
             "fileHTTPUploadGetSlot",
@@ -98,7 +102,7 @@ class XEP_0363:
             async_=True,
         )
         host.plugins["UPLOAD"].register(
-            "HTTP Upload", self.getHTTPUploadEntity, self.fileHTTPUpload
+            "HTTP Upload", self.getHTTPUploadEntity, self.file_http_upload
         )
         # list of callbacks used when a request is done to a component
         self.handlers = []
@@ -151,58 +155,67 @@ class XEP_0363:
 
         return entity
 
-    def _fileHTTPUpload(self, filepath, filename="", upload_jid="",
+    def _file_http_upload(self, filepath, filename="", upload_jid="",
                         ignore_tls_errors=False, profile=C.PROF_KEY_NONE):
         assert os.path.isabs(filepath) and os.path.isfile(filepath)
         client = self.host.getClient(profile)
-        progress_id_d, __ = defer.ensureDeferred(self.fileHTTPUpload(
+        return defer.ensureDeferred(self.file_http_upload(
             client,
             filepath,
             filename or None,
             jid.JID(upload_jid) if upload_jid else None,
             {"ignore_tls_errors": ignore_tls_errors},
         ))
-        return progress_id_d
 
-    async def fileHTTPUpload(
-        self, client, filepath, filename=None, upload_jid=None, options=None):
+    async def file_http_upload(
+        self,
+        client: SatXMPPEntity,
+        filepath: Path,
+        filename: Optional[str] = None,
+        upload_jid: Optional[jid.JID] = None,
+        extra: Optional[dict] = None
+    ) -> Tuple[str, defer.Deferred]:
         """Upload a file through HTTP
 
-        @param filepath(str): absolute path of the file
-        @param filename(None, unicode): name to use for the upload
+        @param filepath: absolute path of the file
+        @param filename: name to use for the upload
             None to use basename of the path
-        @param upload_jid(jid.JID, None): upload capable entity jid,
+        @param upload_jid: upload capable entity jid,
             or None to use autodetected, if possible
-        @param options(dict): options where key can be:
+        @param extra: options where key can be:
             - ignore_tls_errors(bool): if True, SSL certificate will not be checked
+            - attachment(dict): file attachment data
         @param profile: %(doc_profile)s
-        @return (D(tuple[D(unicode), D(unicode)])): progress id and Deferred which fire
-            download URL
+        @return: progress id and Deferred which fire download URL
         """
-        if options is None:
-            options = {}
-        ignore_tls_errors = options.get("ignore_tls_errors", False)
-        filename = filename or os.path.basename(filepath)
-        size = os.path.getsize(filepath)
+        if extra is None:
+            extra = {}
+        ignore_tls_errors = extra.get("ignore_tls_errors", False)
+        file_metadata = {
+            "filename": filename or os.path.basename(filepath),
+            "filepath": filepath,
+            "size": os.path.getsize(filepath),
+        }
 
-        size_adjust = []
-        #: this trigger can be used to modify the requested size, it is notably useful
-        #: with encryption. The size_adjust is a list which can be filled by int to add
-        #: to the initial size
+        #: this trigger can be used to modify the filename or size requested when geting
+        #: the slot, it is notably useful with encryption.
         self.host.trigger.point(
-            "XEP-0363_upload_size", client, options, filepath, size, size_adjust,
-            triggers_no_cancel=True)
-        if size_adjust:
-            size = sum([size, *size_adjust])
+            "XEP-0363_upload_pre_slot", client, extra, file_metadata,
+            triggers_no_cancel=True
+        )
         try:
-            slot = await self.getSlot(client, filename, size, upload_jid=upload_jid)
+            slot = await self.getSlot(
+                client, file_metadata["filename"], file_metadata["size"],
+                upload_jid=upload_jid
+            )
         except Exception as e:
             log.warning(_("Can't get upload slot: {reason}").format(reason=e))
             raise e
         else:
             log.debug(f"Got upload slot: {slot}")
             sat_file = self.host.plugins["FILE"].File(
-                self.host, client, filepath, uid=options.get("progress_id"), size=size,
+                self.host, client, filepath, uid=extra.get("progress_id"),
+                size=file_metadata["size"],
                 auto_end_signals=False
             )
             progress_id = sat_file.uid
@@ -223,7 +236,7 @@ class XEP_0363:
 
 
             await self.host.trigger.asyncPoint(
-                "XEP-0363_upload", client, options, sat_file, file_producer, slot,
+                "XEP-0363_upload", client, extra, sat_file, file_producer, slot,
                 triggers_no_cancel=True)
 
             download_d = agent.request(
@@ -233,8 +246,8 @@ class XEP_0363:
                 file_producer,
             )
             download_d.addCallbacks(
-                self._uploadCb,
-                self._uploadEb,
+                self._upload_cb,
+                self._upload_eb,
                 (sat_file, slot),
                 None,
                 (sat_file,),
@@ -242,7 +255,7 @@ class XEP_0363:
 
             return progress_id, download_d
 
-    def _uploadCb(self, __, sat_file, slot):
+    def _upload_cb(self, __, sat_file, slot):
         """Called once file is successfully uploaded
 
         @param sat_file(SatFile): file used for the upload
@@ -253,7 +266,7 @@ class XEP_0363:
         sat_file.progressFinished({"url": slot.get})
         return slot.get
 
-    def _uploadEb(self, failure_, sat_file):
+    def _upload_eb(self, failure_, sat_file):
         """Called on unsuccessful upload
 
         @param sat_file(SatFile): file used for the upload
diff --git a/sat/plugins/plugin_xep_0446.py b/sat/plugins/plugin_xep_0446.py
index 3d0d5ec5..904341a0 100644
--- a/sat/plugins/plugin_xep_0446.py
+++ b/sat/plugins/plugin_xep_0446.py
@@ -107,19 +107,19 @@ class XEP_0446:
         self,
         file_metadata_elt: domish.Element
     ) -> Dict[str, Any]:
-        """Parse <file-metadata/> element
+        """Parse <file/> element
 
-        @param file_metadata_elt: <file-metadata/> element
+        @param file_metadata_elt: <file/> element
             a parent element can also be used
-        @return: file-metadata data. It's a dict whose keys correspond to
+        @return: file metadata. It's a dict whose keys correspond to
             [get_file_metadata_elt] parameters
-        @raise exceptions.NotFound: no <file-metadata/> element has been found
+        @raise exceptions.NotFound: no <file/> element has been found
         """
 
-        if file_metadata_elt.name != "file-metadata":
+        if file_metadata_elt.name != "file":
             try:
                 file_metadata_elt = next(
-                    file_metadata_elt.elements(NS_FILE_METADATA, "file-metadata")
+                    file_metadata_elt.elements(NS_FILE_METADATA, "file")
                 )
             except StopIteration:
                 raise exceptions.NotFound
@@ -158,7 +158,7 @@ class XEP_0446:
             from sat.tools.xml_tools import pFmtElt
             log.warning("invalid <hash/> element:\n{pFmtElt(file_metadata_elt)}")
         else:
-            data["file_hash"] = (algo, hash_.decode())
+            data["file_hash"] = (algo, hash_)
 
         # TODO: thumbnails
 
diff --git a/sat/plugins/plugin_xep_0447.py b/sat/plugins/plugin_xep_0447.py
index 4e84aae8..bcdfd7c8 100644
--- a/sat/plugins/plugin_xep_0447.py
+++ b/sat/plugins/plugin_xep_0447.py
@@ -15,14 +15,23 @@
 # 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 typing import Optional, Dict, List, Tuple, Union, Any
+from collections import namedtuple
+from functools import partial
+import mimetypes
+from pathlib import Path
+from typing import Any, Callable, Dict, List, Optional, Tuple, Union
 
+import treq
+from twisted.internet import defer
 from twisted.words.xish import domish
 
+from sat.core import exceptions
 from sat.core.constants import Const as C
+from sat.core.core_types import SatXMPPEntity
 from sat.core.i18n import _
 from sat.core.log import getLogger
-from sat.core import exceptions
+from sat.tools import stream
+from sat.tools.web import treq_client_no_ssl
 
 log = getLogger(__name__)
 
@@ -33,23 +42,130 @@ PLUGIN_INFO = {
     C.PI_TYPE: "XEP",
     C.PI_MODES: C.PLUG_MODE_BOTH,
     C.PI_PROTOCOLS: ["XEP-0447"],
-    C.PI_DEPENDENCIES: ["XEP-0103", "XEP-0446"],
+    C.PI_DEPENDENCIES: ["XEP-0103", "XEP-0334", "XEP-0446", "ATTACH", "DOWNLOAD"],
+    C.PI_RECOMMENDATIONS: ["XEP-0363"],
     C.PI_MAIN: "XEP_0447",
     C.PI_HANDLER: "no",
     C.PI_DESCRIPTION: _("""Implementation of XEP-0447 (Stateless File Sharing)"""),
 }
 
 NS_SFS = "urn:xmpp:sfs:0"
+SourceHandler = namedtuple("SourceHandler", ["callback", "encrypted"])
 
 
 class XEP_0447:
     namespace = NS_SFS
 
     def __init__(self, host):
+        self.host = host
         log.info(_("XEP-0447 (Stateless File Sharing) plugin initialization"))
         host.registerNamespace("sfs", NS_SFS)
+        self._sources_handlers = {}
         self._u = host.plugins["XEP-0103"]
+        self._hints = host.plugins["XEP-0334"]
         self._m = host.plugins["XEP-0446"]
+        self._http_upload = host.plugins.get("XEP-0363")
+        self._attach = host.plugins["ATTACH"]
+        self._attach.register(
+            self.can_handle_attachment, self.attach, priority=1000
+        )
+        self.register_source_handler(
+            self._u.namespace, "url-data", self._u.parse_url_data_elt
+        )
+        host.plugins["DOWNLOAD"].register_download_handler(self._u.namespace, self.download)
+        host.trigger.add("messageReceived", self._message_received_trigger)
+
+    def register_source_handler(
+        self, namespace: str, element_name: str,
+        callback: Callable[[domish.Element], Dict[str, Any]],
+        encrypted: bool = False
+    ) -> None:
+        """Register a handler for file source
+
+        @param namespace: namespace of the element supported
+        @param element_name: name of the element supported
+        @param callback: method to call to parse the element
+            get the matching element as argument, must return the parsed data
+        @param encrypted: if True, the source is encrypted (the transmitting channel
+            should then be end2end encrypted to avoir leaking decrypting data to servers).
+        """
+        key = (namespace, element_name)
+        if key in self._sources_handlers:
+            raise exceptions.ConflictError(
+                f"There is already a resource handler for namespace {namespace!r} and "
+                f"name {element_name!r}"
+            )
+        self._sources_handlers[key] = SourceHandler(callback, encrypted)
+
+    async def download(
+        self,
+        client: SatXMPPEntity,
+        attachment: Dict[str, Any],
+        source: Dict[str, Any],
+        dest_path: Union[Path, str],
+        extra: Optional[Dict[str, Any]] = None
+    ) -> Tuple[str, defer.Deferred]:
+        # TODO: handle url-data headers
+        if extra is None:
+            extra = {}
+        try:
+            download_url = source["url"]
+        except KeyError:
+            raise ValueError(f"{source} has missing URL")
+
+        if extra.get('ignore_tls_errors', False):
+            log.warning(
+                "TLS certificate check disabled, this is highly insecure"
+            )
+            treq_client = treq_client_no_ssl
+        else:
+            treq_client = treq
+
+        try:
+            file_size = int(attachment["size"])
+        except (KeyError, ValueError):
+            head_data = await treq_client.head(download_url)
+            file_size = int(head_data.headers.getRawHeaders('content-length')[0])
+
+        file_obj = stream.SatFile(
+            self.host,
+            client,
+            dest_path,
+            mode="wb",
+            size = file_size,
+        )
+
+        progress_id = file_obj.uid
+
+        resp = await treq_client.get(download_url, unbuffered=True)
+        if resp.code == 200:
+            d = treq.collect(resp, file_obj.write)
+            d.addCallback(lambda __: file_obj.close())
+        else:
+            d = defer.Deferred()
+            self.host.plugins["DOWNLOAD"].errback_download(file_obj, d, resp)
+        return progress_id, d
+
+    async def can_handle_attachment(self, client, data):
+        if self._http_upload is None:
+            return False
+        try:
+            await self._http_upload.getHTTPUploadEntity(client)
+        except exceptions.NotFound:
+            return False
+        else:
+            return True
+
+    def get_sources_elt(
+        self,
+        children: Optional[List[domish.Element]] = None
+    ) -> domish.Element:
+        """Generate <sources> element"""
+        sources_elt = domish.Element((NS_SFS, "sources"))
+        if children:
+            for child in children:
+                sources_elt.addChild(child)
+        return sources_elt
 
     def get_file_sharing_elt(
         self,
@@ -75,6 +191,8 @@ class XEP_0447:
         file_sharing_elt = domish.Element((NS_SFS, "file-sharing"))
         if disposition is not None:
             file_sharing_elt["disposition"] = disposition
+        if media_type is None and name:
+            media_type = mimetypes.guess_type(name, strict=False)[0]
         file_sharing_elt.addChild(
             self._m.get_file_metadata_elt(
                 name=name,
@@ -89,7 +207,8 @@ class XEP_0447:
                 thumbnail=thumbnail,
             )
         )
-        sources_elt = file_sharing_elt.addElement("sources")
+        sources_elt = self.get_sources_elt()
+        file_sharing_elt.addChild(sources_elt)
         for source_data in sources:
             if "url" in source_data:
                 sources_elt.addChild(
@@ -102,6 +221,42 @@ class XEP_0447:
 
         return file_sharing_elt
 
+    def parse_sources_elt(
+        self,
+        sources_elt: domish.Element
+    ) -> List[Dict[str, Any]]:
+        """Parse <sources/> element
+
+        @param sources_elt: <sources/> element, or a direct parent element
+        @return: list of found sources data
+        @raise: exceptions.NotFound: Can't find <sources/> element
+        """
+        if sources_elt.name != "sources" or sources_elt.uri != NS_SFS:
+            try:
+                sources_elt = next(sources_elt.elements(NS_SFS, "sources"))
+            except StopIteration:
+                raise exceptions.NotFound(
+                    f"<sources/> element is missing: {sources_elt.toXml()}")
+        sources = []
+        for elt in sources_elt.elements():
+            if not elt.uri:
+                log.warning("ignoring source element {elt.toXml()}")
+                continue
+            key = (elt.uri, elt.name)
+            try:
+                source_handler = self._sources_handlers[key]
+            except KeyError:
+                log.warning(f"unmanaged file sharing element: {elt.toXml}")
+                continue
+            else:
+                source_data = source_handler.callback(elt)
+                if source_handler.encrypted:
+                    source_data[C.MESS_KEY_ENCRYPTED] = True
+                if "type" not in source_data:
+                    source_data["type"] = elt.uri
+                sources.append(source_data)
+        return sources
+
     def parse_file_sharing_elt(
         self,
         file_sharing_elt: domish.Element
@@ -126,17 +281,95 @@ class XEP_0447:
         disposition = file_sharing_elt.getAttribute("disposition")
         if disposition is not None:
             data["disposition"] = disposition
-        sources = data["sources"] = []
         try:
-            sources_elt = next(file_sharing_elt.elements(NS_SFS, "sources"))
-        except StopIteration:
-            raise ValueError(f"<sources/> element is missing: {file_sharing_elt.toXml()}")
-        for elt in sources_elt.elements():
-            if elt.name == "url-data" and elt.uri == self._u.namespace:
-                source_data = self._u.parse_url_data_elt(elt)
-            else:
-                log.warning(f"unmanaged file sharing element: {elt.toXml}")
-                continue
-            sources.append(source_data)
+            data["sources"] = self.parse_sources_elt(file_sharing_elt)
+        except exceptions.NotFound as e:
+            raise ValueError(str(e))
 
         return data
+
+    def _add_file_sharing_attachments(
+            self,
+            client: SatXMPPEntity,
+            message_elt: domish.Element,
+            data: Dict[str, Any]
+    ) -> Dict[str, Any]:
+        """Check <message> for a shared file, and add it as an attachment"""
+        # XXX: XEP-0447 doesn't support several attachments in a single message, thus only
+        #   one attachment can be added
+        try:
+            attachment = self.parse_file_sharing_elt(message_elt)
+        except exceptions.NotFound:
+            return data
+
+        if any(
+                s.get(C.MESS_KEY_ENCRYPTED, False)
+                for s in attachment["sources"]
+        ) and client.encryption.isEncrypted(data):
+            # we don't add the encrypted flag if the message itself is not encrypted,
+            # because the decryption key is part of the link, so sending it over
+            # unencrypted channel is like having no encryption at all.
+            attachment[C.MESS_KEY_ENCRYPTED] = True
+
+        attachments = data['extra'].setdefault(C.MESS_KEY_ATTACHMENTS, [])
+        attachments.append(attachment)
+
+        return data
+
+    async def attach(self, client, data):
+        # XXX: for now, XEP-0447 only allow to send one file per <message/>, thus we need
+        #   to send each file in a separate message
+        attachments = data["extra"][C.MESS_KEY_ATTACHMENTS]
+        if not data['message'] or data['message'] == {'': ''}:
+            extra_attachments = attachments[1:]
+            del attachments[1:]
+        else:
+            # we have a message, we must send first attachment separately
+            extra_attachments = attachments[:]
+            attachments.clear()
+            del data["extra"][C.MESS_KEY_ATTACHMENTS]
+
+        if attachments:
+            if len(attachments) > 1:
+                raise exceptions.InternalError(
+                    "There should not be more that one attachment at this point"
+                )
+            await self._attach.upload_files(client, data)
+            self._hints.addHintElements(data["xml"], [self._hints.HINT_STORE])
+            for attachment in attachments:
+                try:
+                    file_hash = (attachment["hash_algo"], attachment["hash"])
+                except KeyError:
+                    file_hash = None
+                file_sharing_elt = self.get_file_sharing_elt(
+                    [{"url": attachment["url"]}],
+                    name=attachment["name"],
+                    size=attachment["size"],
+                    file_hash=file_hash
+                )
+                data["xml"].addChild(file_sharing_elt)
+
+        for attachment in extra_attachments:
+            # we send all remaining attachment in a separate message
+            await client.sendMessage(
+                to_jid=data['to'],
+                message={'': ''},
+                subject=data['subject'],
+                mess_type=data['type'],
+                extra={C.MESS_KEY_ATTACHMENTS: [attachment]},
+            )
+
+        if ((not data['extra']
+             and (not data['message'] or data['message'] == {'': ''})
+             and not data['subject'])):
+            # nothing left to send, we can cancel the message
+            raise exceptions.CancelError("Cancelled by XEP_0447 attachment handling")
+
+    def _message_received_trigger(self, client, message_elt, post_treat):
+        # we use a post_treat callback instead of "message_parse" trigger because we need
+        # to check if the "encrypted" flag is set to decide if we add the same flag to the
+        # attachment
+        post_treat.addCallback(
+            partial(self._add_file_sharing_attachments, client, message_elt)
+        )
+        return True