try:
    from mod_python import apache, util
except ImportError:
    from dummy import apache, util
import py

__version__ = '0.1 unreleased'

class handler_decorator(object):
    """base class for handler decorators"""
    def __call__(self, handler):
        def wrapper(request):
            return self.handler(handler, request)
        return wrapper

class preparesite(handler_decorator):
    """sets some vars on request"""
    def handler(self, orghandler, request):
        request.form = util.FieldStorage(request)
        request.headers_out['X-Application'] = 'mod_deco v%s' % __version__
        return orghandler(request)

class responsewriter(handler_decorator):
    def handler(self, orghandler, request):
        try:
            ret = orghandler(request)
        except:
            exc, e, tb = py.std.sys.exc_info()
            self.handle_error(request, exc, e, tb)
        else:
            if type(ret) == int:
                # we assume the response has already been written... 
                return ret
            if isinstance(ret, unicode):
                import re
                charset = 'UTF-8'
                match = re.match('charset=.*?;', request.content_type)
                if match:
                    charset = match.group(1)
                ret = ret.encode(charset)
            elif not isinstance(ret, str):
                ret = str(ret)
            request.headers_out['Content-Length'] = str(len(ret))
            request.write(ret)
        return apache.OK

    def handle_error(self, request, exc, e, tb):
        request.content_type = 'text/plain'
        request.status = apache.HTTP_INTERNAL_SERVER_ERROR
        request.write('\n'.join([
            'An exception occurred while handling your request:\n',
            '%s - %s' % (exc, e),
        ] + py.std.traceback.format_tb(tb)))
        apache.log_error('%s - %s' % (exc, e), apache.APLOG_ERR)
        del tb