[FIX][P3] core: correctly handle binary files (base64 encoded) at rpc level

odoo/service/server.py

@@ -961,7 +961,10 @@ def start(preload=None, stop=False):
     """ Start the odoo http server and cron processor.
     """
     global server
+
     load_server_wide_modules()
+    odoo.service.wsgi_server._patch_xmlrpc_marshaller()
+
     if odoo.evented:
         server = GeventServer(odoo.service.wsgi_server.application)
     elif config['workers']:

odoo/service/wsgi_server.py

@@ -88,6 +88,17 @@ def xmlrpc_handle_exception_string(e):
 
     return xmlrpclib.dumps(fault, allow_none=None, encoding=None)
 
+def _patch_xmlrpc_marshaller():
+    # By default, in xmlrpc, bytes are converted to xmlrpclib.Binary object.
+    # Historically, odoo is sending binary as base64 string.
+    # In python 3, base64.b64{de,en}code() methods now works on bytes.
+    # Convert them to str to have a consistent behavior between python 2 and python 3.
+    # TODO? Create a `/xmlrpc/3` route prefix that respect the standard and uses xmlrpclib.Binary.
+    def dump_bytes(marshaller, value, write):
+        marshaller.dump_unicode(odoo.tools.ustr(value), write)
+
+    xmlrpclib.Marshaller.dispatch[bytes] = dump_bytes
+
 def wsgi_xmlrpc(environ, start_response):
     """ Two routes are available for XML-RPC