[IMP] http: LazyResponse rendering w/ concurrent access protection

QWeb's LazyResponse mechanism allows controllers to be inherited
and to alter the rendering context (qwebcontext) *after* calling
super().

However it caused the final rendering to occur outside the protection
of the @service.model.check decorator that handles concurrent access
errors. In rare cases the lazy rendering can be interrupted by
a concurrent access error, for example when bootstrapping the
the cache of asset bundles (as it INSERTs a bunch of attachments).

By forcing the flatten()ing of the lazy response earlier, right
after calling the route's endpoint(), it occurs within the
protection of the @service.model.check, and benefits from the
automatic retry.

flatten() was modified to avoid rendering twice the template
The flatten() in get_response() is still necessary for addons
code that directly calls get_response().

Moved QWebException into openerp.exceptions next to the other
exceptions classes - since it now has more global semantics.

~
The whole request dispatching code could really do with a
complete redesign/simplification.

1 files changed, 12 insertions, 1 deletions

diff --git a/openerp/exceptions.py b/openerp/exceptions.py
index 209f2a4cff2..8d0bb779d3e 100644
--- a/openerp/exceptions.py
+++ b/openerp/exceptions.py
@@ -10,8 +10,9 @@ treated as a 'Server error'.
 If you consider introducing new exceptions, check out the test_exceptions addon.
 """
 
-from inspect import currentframe
 import logging
+from inspect import currentframe
+from lxml import etree
 from tools.func import frame_codeinfo
 
 _logger = logging.getLogger(__name__)
@@ -90,3 +91,13 @@ class DeferredException(Exception):
     def __init__(self, msg, tb):
         self.message = msg
         self.traceback = tb
+
+class QWebException(Exception):
+    def __init__(self, message, **kw):
+        super(QWebException, self).__init__(message)
+        self.qweb = dict(kw)
+
+    def pretty_xml(self):
+        if 'node' not in self.qweb:
+            return ''
+        return etree.tostring(self.qweb['node'], pretty_print=True)