Question

I get a problem in a form handler in app engine (Python). Basically when I post the form to the handler I get the following traceback:

INFO 2011-02-07 14:06:59,364 dev_appserver.py:3317] “GET /favicon.ico HTTP/1.1” 404 –
Traceback (most recent call last):

File “/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/wsgiref/handlers.py”, line 92, in run
self.result = application(self.environ, self.start_response)

File “/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/webapp/__init__.py”, line 531, in __call__
handler.handle_exception(e, self.__debug)

File “/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/webapp/__init__.py”, line 394, in handle_exception
self.error(500)
TypeError: ‘bool’ object is not callable

INFO 2011-02-07 14:07:01,986 dev_appserver.py:3317] “POST /newevent HTTP/1.1” 500 -`

On the browser I get the message ‘A server error occurred. Please contact the administrator’. As you can see, the error happens before the POST command, and doesn’t seem to stem from any of my handler code. Here’s the handler class for that form (post_secure is a method called by the post method in the parent class):

class SaveEvent(BaseHandler):
def post_secure(self):
    userinfo = db.GqlQuery("SELECT * FROM User WHERE fbid = :1", self.user['uid'])[0]
    newevent = Event(parent=userinfo)
    self.error = False
    self.template_values = {}

    if (self.request.get('eventname') == ""):
        self.template_values['eventnameerror'] = True
        self.error = True
    else:
        newevent.eventname = self.request.get('eventname')

    if (self.request.get('venuename') == ""):
        self.template_values['venuenameerror'] = True
        self.error = True
    else:
        newevent.venuename = self.request.get('venuename')

    if (re.match("[0-9]+\.[0-9][0-9]", self.request.get('eventprice')) == None):
        self.template_values['eventpriceerror'] = True
        self.error = True
    else:
        newevent.price_pence = int(float(self.request.get('eventprice')) * 100)

    if (re.match("[0-9][0-9]/[0-9][0-9]/[0-9][0-9][0-9][0-9]", self.request.get('eventdate')) == None):
        self.template_values['eventdateerror'] = True
        self.error = True
    else:
        day = re.split("/", self.request.get('eventdate'))[0]
        month = re.split("/", self.request.get('eventdate'))[1]
        year = re.split("/", self.request.get('eventdate'))[2]

    if (re.match("[0-2][0-9]:[0-5][0-9]", self.request.get('eventtime')) == None):
        self.template_values['eventtimeerror'] = True
        self.error = True
    else:
        hours = re.split(":", self.request.get('eventtime'))[0]
        minutes = re.split(":", self.request.get('eventtime'))[1]

    try:
        newevent.date = datetime.datetime(year, month, day, hours, minutes, 0, 0)
    except ValueError:
        self.template_values['eventdatetimeerror'] = True
        self.error = True

    if (newevent.date < datetime.datetime.now()):
        self.template_values['eventdateerror2'] = True
        self.error = True

    if (self.request.get('eventlink') == ""):
        self.template_values['eventlinkerror'] = True
        self.error = True

    if (self.error == True):
        self.template_values['eventname'] = self.request.get('eventname')
        self.template_values['venuename'] = self.request.get('venuename')
        self.template_values['eventprice'] = self.request.get('eventprice')
        self.template_values['eventdate'] = self.request.get('eventdate')
        self.template_values['eventtime'] = self.request.get('eventtime')
        self.template_values['eventlink'] = self.request.get('eventlink')
        self.tpl('addevent.html', self.template_values)

    newevent.put()

    self.template_values = {
        'newevent' : newevent
    }

    self.tpl('eventadded.html', self.template_values)

Answer 1

The RequestHandler class has a method named error

error(code)

A shortcut method for handlers to use to return an error response. Clears the response output stream and sets the HTTP error code to code. Equivalent to calling self.response.clear() and self.response.set_status(code).

Your POST handler above overwrites that method with a boolean value, and then when the framework attempts to call self.error(500) it throws an exception because the value of self.error is no longer a callable.

Use a different member variable name than error to prevent this.