Question

我正在进行Udacity的网络开发课程，而我在第2课第35课中遇到了问题。这是我的代码。

import webapp2

form="""
<form method="post">
    What is your birthdate?
    <br>
    <label> Month
        <input type="text" name="month">
    </label>
    <label> Day
        <input type="text" name="day">
    </label>
    <label> Year
        <input type="text" name="year">
    </label>
    <br>
    <br>
    <input type="submit">
</form>
"""

class MainPage(webapp2.RequestHandler):
    months = ['January','February','March','April','May','June','July',
          'August','September','October','November','December']
    months_abbvs = dict((m[:3].lower(), m) for m in months)


    def valid_month(month):
        if month:
            short_month = month[:3].lower()
            if short_month in months:
                return months_abbvs.get(short_month)

    def valid_day(day):
        if day and day.isdigit():
            day = int(day)
            if day > 0 and day <= 31:
                return day

    def valid_year(year):
        if year and year.isdigit():
            year = int(year)
            if year >= 1900 and year <= 2020:
                return year

    def get(self):
        self.response.write(form)

    def post(self):
        user_month = valid_month(self.request.get('month'))
        user_day = valid_day(self.request.get('day'))
        user_year = valid_year(self.request.get('year'))

        if not (user_month and user_day and user_day):
            self.response.out.write(form)
        else:
            self.response.write("Thanks! That's a totally calid day!")

app = webapp2.WSGIApplication([
        ('/', MainPage)], debug=True)

我通过谷歌应用引擎运行它。当我在浏览器中单击表单上的提交时，我得到：

This page isn’t working

localhost is currently unable to handle this request.
HTTP ERROR 500

当我查看运行服务器的cmd提示时，我收到错误：

INFO     2017-11-01 22:09:22,153 module.py:821] default: "GET / HTTP/1.1" 
200 382
ERROR    2017-11-02 02:09:46,470 webapp2.py:1528] global name 
'valid_month' is not defined
Traceback (most recent call last):
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1511, in 
__call__
rv = self.handle_exception(request, response, e)
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1505, in 
__call__
rv = self.router.dispatch(request, response)
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1253, in 
default_dispatcher
return route.handler_adapter(request, response)
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1077, in 
__call__
return handler.dispatch()
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 547, in 
dispatch
return self.handle_exception(e, self.app.debug)
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 545, in 
dispatch
return method(*args, **kwargs)
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\python-docs-
samples\appengine\standard\hello_world\main.py", line 50, in post
user_month = valid_month(self.request.get('month'))
NameError: global name 'valid_month' is not defined
ERROR    2017-11-02 02:09:46,470 wsgi.py:279]
Traceback (most recent call last):
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\google\appengine\runtime\wsgi.py", line 
267, in Handle
INFO     2017-11-01 22:09:46,477 module.py:821] default: "POST / 
HTTP/1.1" 500 -
result = handler(dict(self._environ), self._StartResponse)
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1519, in 
__call__
response = self._internal_error(e)
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1511, in 
__call__
rv = self.handle_exception(request, response, e)
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1505, in 
__call__
rv = self.router.dispatch(request, response)
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1253, in 
default_dispatcher
return route.handler_adapter(request, response)
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 1077, in 
__call__
return handler.dispatch()
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 547, in 
dispatch
return self.handle_exception(e, self.app.debug)
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\google-cloud-
sdk\platform\google_appengine\lib\webapp2-2.3\webapp2.py", line 545, in 
dispatch
return method(*args, **kwargs)
File "C:\Users\mmelv\AppData\Local\Google\Cloud SDK\python-docs-
samples\appengine\standard\hello_world\main.py", line 50, in post
user_month = valid_month(self.request.get('month'))
NameError: global name 'valid_month' is not defined

据我所知，问题在于 user_month = valid_month（self.request.get（＆＃39; month））虽然我已尝试将缩进从空格更改为制表符并返回空格，重写整个代码，然后重新启动服务器，但都无济于事。有人帮帮我...

Answer 1

当从它们所属的类中调用成员函数时，需要在self.前面加上它们。此外，您的所有成员函数（例如valid_month()，valid_day()和valid_year()都必须self作为其实际参数的第一个值。此外，对months和months_abbvs等静态类变量的任何引用也必须以self.开头。

此外，valid_month()，valid_day()和valid_year()的返回值可能存在逻辑错误。每个都返回一个字符串，但post()中的条件是评估这三个是否True。此外，valid_months()中的条件可能是为了检查short_month是否在months_abbvs而不是months。

尝试使用以下内容替换当前的post()函数：

def post(self):

    user_month = self.valid_month(self.request.get("month"))
    user_day   = self.valid_day(self.request.get("day"))
    user_year  = self.valid_year(self.request.get("year"))

    if not(user_month and user_day and user_day):

        self.response.out.write(form)

    else:

        self.response.write("Thanks! That's a totally calid day!")

然后更改以下函数标题：

对于valid_month()，请使用以下内容替换现有函数：

def valid_month(self, month):

    if month:

        short_month = month[:3].lower()

        if short_month in self.months_abbvs:

            return True

对于valid_day()，请使用以下内容替换现有函数：

def valid_day(self, day):

    if day and day.isdigit():

        day = int(day)

        if day > 0 and day <= 31:

            return True

对于valid_year()，请使用以下内容替换现有函数：

def valid_year(self, year):

    if year and year.isdigit():

        year = int(year)

        if year >= 1900 and year <= 2020:

            return True

NameError：全局名称＆＃39; valid_month＆＃34;没有定义

1 个答案: