[web] add a digital signature to error form (closes #2522526)
Simple (and quite weak) implementation of a digital signature of the content
to be submited by email in the error report view generated by ErrorView.
The signature is a simple hmac hash computed using a secret key (generated at
repository startup) and the "secret" form content to be included in the
notification email. The controller can then check this content has not been
modified or forged by a malicious user.
# copyright 2003-2010 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb. If not, see <http://www.gnu.org/licenses/>.
""" CW - nevow/twisted client
"""