FileTransporter错误UnboundLocalError:在assignmen之前引用了局部变量“classname”

Question

我正在使用fileconvayor表单https://github.com/wimleers/fileconveyor

但是当我运行脚本时，我得到了以下错误。在

Traceback (most recent call last):
File "arbitrator.py", line 1185, in <module>
run_file_conveyor()
File "arbitrator.py", line 1168, in run_file_conveyor
arbitrator = Arbitrator(os.path.join(FILE_CONVEYOR_PATH, "config.xml"), rest
art)
File "arbitrator.py", line 142, in __init__
transporter_class = self._import_transporter(transporter_name)
File "arbitrator.py", line 1162, in _import_transporter
self.logger.error("The Transporter module '%s' was found, but its Transporte
r class '%s' could not be found."  % (module_name, classname))
UnboundLocalError: local variable 'classname' referenced before assignment
[root@af-server fileconveyor]#

这是来自仲裁员.py142号线

^{pr2}$

以及1162行的代码

transporter_class = None
    module = None
    alternatives = [transporter]
    default_prefix = 'transporters.transporter_' # Not  'fileconveyor.transporters.transporter_'!
    if not transporter.startswith(default_prefix):
        alternatives.append('%s%s' % (default_prefix, transporter))
    for module_name in alternatives:
        try:
            module = __import__(module_name, globals(), locals(), ["TRANSPORTER_CLASS"], -1)
        except ImportError:
            pass
    if not module:
        msg = "The transporter module '%s' could not be found." % transporter
        if len(alternatives) > 1:
            msg = '%s Tried (%s)' % (msg, ', '.join(alternatives))
        self.logger.error(msg)
    else:
        try:
            classname = module.TRANSPORTER_CLASS
            module = __import__(module_name, globals(), locals(), [classname])
            transporter_class = getattr(module, classname)
        except AttributeError:
            self.logger.error("The Transporter module '%s' was found, but its Transporter class '%s' could not be found."  % (module_name, classname))
    return transporter_class

这是文件中的全部代码

http://pastebin.com/ctsLrckq

Answer 1

这条线：

classname = module.TRANSPORTER_CLASS

引发AttributeError异常，因为module没有TRANSPORTER_CLASS属性。这会导致解释器在定义self.logger.error(...)变量之前跳到self.logger.error(...)行。当记录器行尝试使用未定义的变量时，格式化日志字符串失败。为了修复它，您可以将记录器线路替换为以下线路：

^{pr2}$

请注意，__import__可以引发ImportError，这是不捕获的。我想这段代码的作者是想抓住它。在

Answer 2

当我按照指南安装FileTransporter时，也遇到了同样的错误安装.txt. 似乎有一些未解决的依赖关系。尝试用以下方法解决：

pip install django-cumulus==1.0.10

Answer 3

例外情况是捕捉到一个比您想象的早两行的错误：它出现在classname = module.TRANSPORTER_CLASS中。无论module是什么，它没有TRANSPORTER\u类attribute, so an exception is raised andclassname`从未定义。如果你没有吞下实际的错误消息，那就很清楚了。在

但我必须说，这个代码没有什么意义。在那个else子句中，您已经有了module，那么为什么要在下面的行中重新导入它？在