try:

            str_repo_name = environ['REPO_NAME'] = self.__get_repository(environ)

            assert isinstance(str_repo_name, str), str_repo_name

            repo_name = safe_unicode(str_repo_name)

            assert safe_str(repo_name) == str_repo_name, (str_repo_name, repo_name)

            log.debug('Extracted repo name is %s', repo_name)

        except Exception as e:

            log.error('error extracting repo_name: %r', e)

            return HTTPInternalServerError()(environ, start_response)

        # quick check if that dir exists...

        if not is_valid_repo(repo_name, self.basepath, 'hg'):

            return HTTPNotFound()(environ, start_response)

        #======================================================================

        # GET ACTION PULL or PUSH

        #======================================================================

        try:

            action = self.__get_action(environ)

        except HTTPBadRequest as e:

            return e(environ, start_response)

        #======================================================================

        # CHECK PERMISSIONS

        #======================================================================

        user, response_app = self._authorize(environ, start_response, action, repo_name, ip_addr)

        if response_app is not None:

            return response_app(environ, start_response)

        # extras are injected into mercurial UI object and later available

        # in hg hooks executed by kallithea

        from kallithea import CONFIG

        server_url = get_server_url(environ)

        extras = {

            'ip': ip_addr,

            'username': user.username,

            'action': action,

            'repository': repo_name,

            'scm': 'hg',

            'config': CONFIG['__file__'],

            'server_url': server_url,

            'make_lock': None,

            'locked_by': [None, None]

        }

        #======================================================================

        # MERCURIAL REQUEST HANDLING

        #======================================================================

        repo_path = os.path.join(safe_str(self.basepath), str_repo_name)

        log.debug('Repository path is %s', repo_path)

        # A Mercurial HTTP server will see listkeys operations (bookmarks,

        # phases and obsolescence marker) in a different request - we don't

        # want to check locking on those

        if environ['QUERY_STRING'] == 'cmd=listkeys':

            pass

        # CHECK LOCKING only if it's not ANONYMOUS USER

        elif not user.is_default_user:

            log.debug('Checking locking on repository')

            make_lock, locked, locked_by = check_locking_state(action, repo_name, user)

            # store the make_lock for later evaluation in hooks

            extras.update({'make_lock': make_lock,

                           'locked_by': locked_by})

        fix_PATH()

        log.debug('HOOKS extras is %s', extras)

        baseui = make_ui('db')

        self.__inject_extras(repo_path, baseui, extras)

        try:

            log.info('%s action on Mercurial repo "%s" by "%s" from %s',

                     action, str_repo_name, safe_str(user.username), ip_addr)

            app = self.__make_app(repo_path, baseui, extras)

            result = app(environ, start_response)

            if action == 'push':

                result = WSGIResultCloseCallback(result,

                    lambda: self._invalidate_cache(repo_name))

            return result

        except RepoError as e:

            if str(e).find('not found') != -1:

                return HTTPNotFound()(environ, start_response)

        except HTTPLockedRC as e:

            # Before Mercurial 3.6, lock exceptions were caught here

            log.debug('Locked, response %s: %s', e.code, e.title)

            return e(environ, start_response)

        except Exception:

            log.error(traceback.format_exc())

            return HTTPInternalServerError()(environ, start_response)

    def __make_app(self, repo_name, baseui, extras):

        """

        Make an wsgi application using hgweb, and inject generated baseui

        instance, additionally inject some extras into ui object

        """

        class HgWebWrapper(hgweb_mod.hgweb):

            # Work-around for Mercurial 3.6+ causing lock exceptions to be

            # thrown late

                try:

                except HTTPLockedRC as e:

                    log.debug('Locked, response %s: %s', e.code, e.title)

                    req.respond(e.status, 'text/plain')

                    return ''

        return HgWebWrapper(repo_name, name=repo_name, baseui=baseui)

    def __get_repository(self, environ):

        """

        Gets repository name out of PATH_INFO header

        :param environ: environ where PATH_INFO is stored

        """

        try:

            environ['PATH_INFO'] = self._get_by_id(environ['PATH_INFO'])

            repo_name = '/'.join(environ['PATH_INFO'].split('/')[1:])

            if repo_name.endswith('/'):

                repo_name = repo_name.rstrip('/')

        except Exception:

            log.error(traceback.format_exc())

            raise

        return repo_name

    def __get_action(self, environ):

        """

        Maps mercurial request commands into a pull or push command.

        Raises HTTPBadRequest if the request environment doesn't look like a hg client.

        """

        mapping = {'unbundle': 'push',

                   'pushkey': 'push'}

        for qry in environ['QUERY_STRING'].split('&'):

            if qry.startswith('cmd'):

                cmd = qry.split('=')[-1]

                return mapping.get(cmd, 'pull')

        # Note: the client doesn't get the helpful error message

        raise HTTPBadRequest('Unable to detect pull/push action! Are you using non standard command or client?')

    def __inject_extras(self, repo_path, baseui, extras=None):

        """

        Injects some extra params into baseui instance

        also overwrites global settings with those takes from local hgrc file

        :param baseui: baseui instance

        :param extras: dict with extra params to put into baseui

        """

        hgrc = os.path.join(repo_path, '.hg', 'hgrc')

        repoui = make_ui('file', hgrc)

        if repoui:

            # overwrite our ui instance with the section from hgrc file

            for section in ui_sections:

                for k, v in repoui.configitems(section):

                    baseui.setconfig(section, k, v)

        _set_extras(extras or {})