[FIX] fastapi: Compatibility with latest Odoo

From odoo/odoo@cb1d057, the orignal werkzeug request is wrapped in a dedicated class to keep under control the attributes developers use. This change add code to make the fastapi addon working with version including this last change and prior version

refs OCA#414

fastapi/fastapi_dispatcher.py

@@ -48,8 +48,19 @@ def _make_response(self, status_mapping, headers_tuple, content):
         self.headers = dict(headers_tuple)
 
     def _get_environ(self):
-        environ = self.request.httprequest.environ
-        environ["wsgi.input"] = self.request.httprequest._get_stream_for_parsing()
+        try:
+            # normal case after
+            # https://github.com/odoo/odoo/commit/cb1d057dcab28cb0b0487244ba99231ee292502e
+            httprequest = self.request.httprequest._HTTPRequest__wrapped
+        except AttributeError:
+            # fallback for older odoo versions
+            # The try except is the most efficient way to handle this
+            # as we expect that most of the time the attribute will be there
+            # and this code will no more be executed if it runs on an up to
+            # date odoo version. (EAFP: Easier to Ask for Forgiveness than Permission)
+            httprequest = self.request.httprequest
+        environ = httprequest.environ
+        environ["wsgi.input"] = httprequest._get_stream_for_parsing()
         return environ
 
     @contextmanager