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

        # GET ACTION PULL or PUSH

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

        action = self.__get_action(environ)

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

        # CHECK ANONYMOUS PERMISSION

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

        if action in ['pull', 'push']:

            anonymous_user = self.__get_user('default')

            username = anonymous_user.username

            if anonymous_user.active:

                # ONLY check permissions if the user is activated

                anonymous_perm = self._check_permission(action, anonymous_user,

                                                        repo_name, ip_addr)

            else:

                anonymous_perm = False

            if not anonymous_user.active or not anonymous_perm:

                if not anonymous_user.active:

                    log.debug('Anonymous access is disabled, running '

                              'authentication')

                if not anonymous_perm:

                    log.debug('Not enough credentials to access this '

                              'repository as anonymous user')

                username = None

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

                # DEFAULT PERM FAILED OR ANONYMOUS ACCESS IS DISABLED SO WE

                # NEED TO AUTHENTICATE AND ASK FOR AUTH USER PERMISSIONS

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

                # try to auth based on environ, container auth methods

                log.debug('Running PRE-AUTH for container based authentication')

                pre_auth = auth_modules.authenticate('', '', environ)

                if pre_auth and pre_auth.get('username'):

                    username = pre_auth['username']

                log.debug('PRE-AUTH got %s as username' % username)

                # If not authenticated by the container, running basic auth

                if not username:

                    self.authenticate.realm = \

                        safe_str(self.config['realm'])

                    result = self.authenticate(environ)

                    if isinstance(result, str):

                        AUTH_TYPE.update(environ, 'basic')

                        REMOTE_USER.update(environ, result)

                        username = result

                    else:

                        return result.wsgi_application(environ, start_response)

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

                # CHECK PERMISSIONS FOR THIS REQUEST USING GIVEN USERNAME

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

                try:

                    user = self.__get_user(username)

                    if user is None or not user.active:

                        return HTTPForbidden()(environ, start_response)

                    username = user.username

                except Exception:

                    log.error(traceback.format_exc())

                    return HTTPInternalServerError()(environ, start_response)

                #check permissions for this repository

                perm = self._check_permission(action, user, repo_name, ip_addr)

                if not perm:

                    return HTTPForbidden()(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': 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

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

        str_repo_name = safe_str(repo_name)

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

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

        # CHECK LOCKING only if it's not ANONYMOUS USER

        if username != User.DEFAULT_USER:

            log.debug('Checking locking on repository')

            (make_lock,

             locked,

             locked_by) = self._check_locking_state(

                            environ=environ, action=action,

                            repo=repo_name, user_id=user.user_id

                       )

            # 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(username), ip_addr))

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

            return app(environ, start_response)

        except RepoError, e:

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

                return HTTPNotFound()(environ, start_response)

        except HTTPLockedRC, e:

            _code = CONFIG.get('lock_ret_code')

            log.debug('Repository LOCKED ret code %s!' % (_code))

            return e(environ, start_response)

        except Exception:

            log.error(traceback.format_exc())

            return HTTPInternalServerError()(environ, start_response)

        finally:

            # invalidate cache on push

            if action == 'push':

                self._invalidate_cache(repo_name)

    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

        """

        return hgweb_mod.hgweb(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_user(self, username):

        return User.get_by_username(username)

    def __get_action(self, environ):

        """

        Maps mercurial request commands into a clone,pull or push command.

        This should always return a valid command string

        :param environ:

        """

        mapping = {'changegroup': 'pull',

                   'changegroupsubset': 'pull',

                   'stream_out': 'pull',

                   'listkeys': 'pull',

                   'unbundle': 'push',

                   'pushkey': 'push', }

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

            if qry.startswith('cmd'):

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

                if cmd in mapping:

                    return mapping[cmd]

                return 'pull'

        raise Exception('Unable to detect pull/push action !!'

                        'Are you using non standard command or client ?')

    def __inject_extras(self, repo_path, baseui, extras={}):

        """

        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, False)

        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)