[hooks/syncschema] only call "ALTER TABLE" once when changing a size constraint
Until now we would:
- remove the old size constraint from the in-memory schema
- call update_rdef_column which removes the size restriction from the
column's type
- add the new constraint object
- call update_rdef_column which adds the size restriction back
This breaks on SQL Server when the column is involved in an index (e.g.
as part of a multi-column unique constraint), because in the
intermediate stage the column's type is "nvarchar(max)", which is not
indexable.
Of course we must still detect the case where a size constraint is
really dropped and update the db schema accordingly.
Closes #5557633.
"""twisted server for CubicWeb web instances
:organization: Logilab
:copyright: 2001-2011 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
"""
__docformat__ = "restructuredtext en"
class HTTPResponse(object):
"""An object representing an HTTP Response to be sent to the client.
"""
def __init__(self, twisted_request, code=None, headers=None, stream=None):
self._headers_out = headers
self._twreq = twisted_request
self._stream = stream
self._code = code
self._init_headers()
self._finalize()
def _init_headers(self):
if self._headers_out is None:
return
# initialize headers
for k, values in self._headers_out.getAllRawHeaders():
self._twreq.responseHeaders.setRawHeaders(k, values)
# add content-length if not present
if (self._headers_out.getHeader('content-length') is None
and self._stream is not None):
self._twreq.setHeader('content-length', len(self._stream))
def _finalize(self):
# we must set code before writing anything, else it's too late
if self._code is not None:
self._twreq.setResponseCode(self._code)
if self._stream is not None:
self._twreq.write(str(self._stream))
self._twreq.finish()
def __repr__(self):
return "<%s.%s code=%d>" % (self.__module__, self.__class__.__name__, self._code)