"""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

"""

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):

        # cw_failed is set on errors such as "connection aborted by client". In

        # such cases, req.finish() was already called and calling it a twice

        # would crash

        if getattr(self._twreq, 'cw_failed', False):

            return

        # 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)