CODEWITHSUNDEEP
djangodjango-models
Deepend
Deepend

Reputation: 4155

How to store incremental counter variables in a `class Counter(models.Model):` and therefore the Database?

I am building/built a small survey application which is meant to direct users to one of 9 surveys. It does this my appending the URL with the name of the survey e.g. /surveyone/, /surveytwo/ etc.

Each path/survey has a maximum amount of times it should be seen, e.g. PathMax = 3 and the total number of competed surveys (all 9 paths) cannot exceed, 20 e.g. TotalMax = 20

When a survey is complete a counter is incremented in the done() method e.g. SurveyWizardOneCounter += 1 and this is checked against the PathMax when assigning a participant their path.

The Problem:

The code below works fine on my local machine, however on the server the counter variables TotalMaxCounter and e.g. SurveyWizardOneCounter never increment past 1. I believe this is because they are getting reset to 0 at the top of the file.

Can anyone tell me how to get past this? Where can/should I store the counter variables so that I can update them and access them without them getting overwritten?

Suspicions:

I believe I should be storing these counter variables in a model/database e.g. class Counter(models.Model): but I am not really sure how to do this or how to access them.

I have never really used/learned database before and have just about managed to set one up (MySQL) to store a Person model with the data from my survey application.

views.py

PathMax = 3 
TotalMax = 20
TotalMaxCounter = 0

SurveyWizardOneCounter = 0
SurveyWizardTwoCounter = 0 
SurveyWizardThreeCounter = 0 
SurveyWizardFourCounter = 0 
SurveyWizardFiveCounter = 0 
SurveyWizardSixCounter = 0 
SurveyWizardSevenCounter = 0 
SurveyWizardEightCounter = 0 
SurveyWizardNineCounter = 0



def begin(request):
    global TotalMaxCounter    
    if TotalMaxCounter < TotalMax:    

        survey_url = random.choice(SURVEY_URLS)
        print 'You are looking at:', survey_url        

        if survey_url == '/surveyone/':     
            if SurveyWizardOneCounter > PathMax:
                SURVEY_URLS.pop(0)

        elif survey_url == '/surveytwo/':
            if SurveyWizardTwoCounter > PathMax:
                SURVEY_URLS.pop(1)

        elif survey_url == '/surveythree/':
            if SurveyWizardThreeCounter > PathMax:
                SURVEY_URLS.pop(2)

        elif survey_url == '/surveyfour/':
            if SurveyWizardFourCounter > PathMax:
                SURVEY_URLS.pop(3)

        elif survey_url == '/surveyfive/':
            if SurveyWizardFiveCounter > PathMax:
                SURVEY_URLS.pop(4)

        elif survey_url == '/surveysix/':
            if SurveyWizardSixCounter > PathMax:
                SURVEY_URLS.pop(5)

        elif survey_url == '/surveyseven/':
            if SurveyWizardSevenCounter > PathMax:
                SURVEY_URLS.pop(6)                

        elif survey_url == '/surveyeight/':
            if SurveyWizardEightCounter > PathMax:
                SURVEY_URLS.pop(7)   

        elif survey_url == '/surveynine/':
            if SurveyWizardNineCounter > PathMax:
                SURVEY_URLS.pop(8)  

        return render(request, 'Begin.html', {'survey_url': survey_url})    
    else:
        return render(request, 'surveyfull.html')






class SurveyWizardOne(SessionWizardView):                             
    def get_context_data(self, form, **kwargs):
        context = super(SurveyWizardOne, self).get_context_data(form, **kwargs)                      
        ...
        ....

        return context 


    def done(self, form_list, **kwargs):
        global SurveyWizardOneCounter
        global TotalMaxCounter 
        SurveyWizardOneCounter += 1   
        TotalMaxCounter += 1

        logger.debug('\n\n SurveyWizardOneCounter = %s', SurveyWizardOneCounter)
        logger.debug('\n\n TotalMaxCounter = %s', TotalMaxCounter)

        for form in form_list:
            form.save()

        return render(self.request, 'Return_to_AMT.html', {
            'form_data': [form.cleaned_data for form in form_list],            
        })

Upvotes: 0

Views: 85

Answers (1)

NeoWang
NeoWang

Reputation: 18513

Do not save anything in a global variable in a web app. Requests are handled in different sessions, very possibly different python interpreter instances, global variable set in one session is not visible in another session.

Counters can be saved in database, as an extra field in the Survey model, and the total count can be calculated by Sum on this field.

Upvotes: 1

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