收到 TypeError，“不可索引”在 webapp2.RequestHandler 的 post 方法中执行 if self.request.POST['file'] 时

Question

我正在尝试使用此代码上传文件：

<form id="form1" action="convert" enctype="multipart/form-data" method="post">
    <input type="file" name="file"/>
    <div><input id="submit_button" type="submit" value="Upload"/></div>
</form>

class Convert(RequestHandler):
    @login_required
    def post(self):
        session = Session(writer="cookie", session_expire_time = 3600, set_cookie_expires = True)
        if session['id']:
            file = self.request.POST['file']
            if file and file.type and file.value:

但我不断收到此错误：

if file and file.type and file.value:
  File "C:\Python25\lib\cgi.py", line 633, in __len__
    return len(self.keys())
  File "C:\Python25\lib\cgi.py", line 609, in keys
    raise TypeError, "not indexable"

有趣的是，这曾经有效！这里出了什么问题？请注意，我使用的是 webapp2。

以及 此页面显示：FieldStorage 实例可以像 Python 字典一样进行索引。它允许使用 in 运算符进行成员资格测试，并且还支持标准字典方法 keys() 和内置函数 len()

完整堆栈跟踪：

Traceback (most recent call last):
  File "C:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 3858, in _HandleRequest
    self._Dispatch(dispatcher, self.rfile, outfile, env_dict)
  File "C:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 3792, in _Dispatch
    base_env_dict=env_dict)
  File "C:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 580, in Dispatch
    base_env_dict=base_env_dict)
  File "C:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 2918, in Dispatch
    self._module_dict)
  File "C:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 2822, in ExecuteCGI
    reset_modules = exec_script(handler_path, cgi_path, hook)
  File "C:\Program Files\Google\google_appengine\google\appengine\tools\dev_appserver.py", line 2704, in ExecuteOrImportScript
    script_module.main()
  File "C:\myproject\main.py", line 16, in main
    run_wsgi_app(application)
  File "C:\Program Files\Google\google_appengine\google\appengine\ext\webapp\util.py", line 98, in run_wsgi_app
    run_bare_wsgi_app(add_wsgi_middleware(application))
  File "C:\Program Files\Google\google_appengine\google\appengine\ext\webapp\util.py", line 116, in run_bare_wsgi_app
    result = application(env, _start_response)
  File "C:\myproject\webapp2\__init__.py", line 1053, in __call__
    return self.wsgi_app(environ, start_response)
  File "C:\myproject\webapp2\__init__.py", line 1098, in wsgi_app
    self.handle_exception(request, response, e)
  File "C:\myproject\webapp2\__init__.py", line 1092, in wsgi_app
    self.router.dispatch(self, request, response, match)
  File "C:\myproject\webapp2\__init__.py", line 949, in dispatch
    handler.handle_exception(e, app.debug)
  File "C:\myproject\webapp2\__init__.py", line 942, in dispatch
    getattr(handler, method)(*args)
  File "C:\myproject\py\decorators.py", line 15, in decorated
    return _login_required (self) or func(self, *args, **kwargs)
  File "C:\myproject\py\document.py", line 42, in post
    if file and file.type and file.value:
  File "C:\Python25\lib\cgi.py", line 633, in __len__
    return len(self.keys())
  File "C:\Python25\lib\cgi.py", line 609, in keys
    raise TypeError, "not indexable"
TypeError: not indexable

我修复它的方法是撕掉 if file:并使用 python has_key 方法检查 self.request.POST 是否具有密钥“文件”

Answer 1

我在您的代码片段或堆栈跟踪中没有看到足够的数据来判断错误来自何处。相反，这里有一个完整的工作上传示例：

http ://blog.notdot.net/2009/9/Handling-file-uploads-in-App-Engine