ext.py 文件源码

def setup(self):
        # we clear this out for various reasons.  The most important one is
        # that a real flaskext could be in there which would disable our
        # fake package.  Secondly we want to make sure that the flaskext
        # import hook does not break on reloading.
        for entry, value in list(sys.modules.items()):
            if (entry.startswith('flask.ext.') or
                entry.startswith('flask_') or
                entry.startswith('flaskext.') or
                entry == 'flaskext') and value is not None:
                sys.modules.pop(entry, None)
        from flask import ext
        reload_module(ext)

        # reloading must not add more hooks
        import_hooks = 0
        for item in sys.meta_path:
            cls = type(item)
            if cls.__module__ == 'flask.exthook' and \
               cls.__name__ == 'ExtensionImporter':
                import_hooks += 1
        self.assert_equal(import_hooks, 1)