plugin upload, XEP-0363: code modernisation + preparation for extension:

- use of async/await syntax
- fileUpload's options are now serialised, allowing non string values
- (XEP-0363) Slot is now a dataclass, so it can be modified by other plugins
- (XEP-0363) Moved SSL related code to the new tools.web module
- (XEP-0363) added `XEP-0363_upload_size` and `XEP-0363_upload` trigger points
- a Deferred is not used anymore for `progress_id`, the value is directly returned

sat/tools/web.py

@@ -0,0 +1,67 @@
+#!/usr/bin/env python3
+
+# SàT: an XMPP client
+# Copyright (C) 2009-2019 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 OpenSSL import SSL
+from zope.interface import implementer
+from treq.client import HTTPClient
+from twisted.internet.interfaces import IOpenSSLClientConnectionCreator
+from twisted.internet import reactor, ssl
+from twisted.web import iweb
+from twisted.web import client as http_client
+from sat.core.log import getLogger
+
+
+log = getLogger(__name__)
+
+
+SSLError = SSL.Error
+
+
+@implementer(IOpenSSLClientConnectionCreator)
+class NoCheckConnectionCreator(object):
+    def __init__(self, hostname, ctx):
+        self._ctx = ctx
+
+    def clientConnectionForTLS(self, tlsProtocol):
+        context = self._ctx
+        connection = SSL.Connection(context, None)
+        connection.set_app_data(tlsProtocol)
+        return connection
+
+
+@implementer(iweb.IPolicyForHTTPS)
+class NoCheckContextFactory(ssl.ClientContextFactory):
+    """Context factory which doesn't do TLS certificate check
+
+    /!\\ it's obvisously a security flaw to use this class,
+    and it should be used only with explicit agreement from the end used
+    """
+
+    def creatorForNetloc(self, hostname, port):
+        log.warning(
+            "TLS check disabled for {host} on port {port}".format(
+                host=hostname, port=port
+            )
+        )
+        certificateOptions = ssl.CertificateOptions(trustRoot=None)
+        return NoCheckConnectionCreator(hostname, certificateOptions.getContext())
+
+
+#: following treq doesn't check TLS, obviously it is unsecure and should not be used
+#: without explicit warning
+treq_no_ssl = HTTPClient(http_client.Agent(reactor, NoCheckContextFactory))