Best way to code multiple decisions in Python

Question

I have the following practical problem (related to Django/Python).

I'm trying to get the following in the most efficient piece of Python code ->

There are 2 items to be checked:

Is the user logged in? if not show a login page, else check if the request is a post request.

Is the request a post request? If not show a form, else handle the form

def upload(request):
if request.user.is_authenticated:
    if request.method == 'POST':
        form = forms.DocumentForm()
        return HttpResponse('Handle POST and LoggedIn Prefix Form Validation')
    else:
        return HttpResponse('POST but not logged in')
        return render(request, 'upload.html', {'form': form}
else:
    return HttpResponse('Not Logged In Need to Make Error Landing Page')

Two if-else statements are very efficient. Is there any specific reason you're unhappy with the performance of the code? — Jonas, May 31 '18 at 07:32
@Jonas I was/am not sure about the last Else statement. But reading your comment the current code will do the job? — BartD, May 31 '18 at 07:45
Yes, current code will be about as efficient as you're going to get. — Jonas, May 31 '18 at 07:47

score 0 · Accepted Answer · answered May 31 '18 at 07:45

i think this is quite pythonic...

def upload(request):
    if not request.user.is_authenticated:
        #return early
        return HttpResponse('Not Logged In Need to Make Error Landing Page')

    # this will only be reached if user authenticated
    if request.method == 'POST':
        form = forms.DocumentForm()
        return HttpResponse('Handle POST and LoggedIn Prefix Form Validation')
    else:
        pass # handle GET

If you need to check the authentication in multiple functions, consider using a decorator instead

@authenticated_users_only(request)
def upload(request):   
    if request.method == 'POST':
        form = forms.DocumentForm()
        return HttpResponse('Handle POST and LoggedIn Prefix Form Validation')
    else:
        pass # handle GET

If you don't know how to write a decorator yet - read this

score 0 · Answer 2 · answered May 31 '18 at 07:49

0

Avoid else when possible and use early return:

def upload(request):
    if request.user.is_authenticated:
        if request.method != 'POST':
            return HttpResponse('Not Logged In Need to Make Error Landing Page')
        form = forms.DocumentForm()
        return HttpResponse('Handle POST and LoggedIn Prefix Form Validation')

    if request.method == 'POST':
        return HttpResponse('POST but not logged in')

answered May 31 '18 at 07:49

Juan Diego Godoy Robles

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Thanks for the helpful hint here. Read some about early return and it obviously clarifies a lot. – BartD May 31 '18 at 07:55

Best way to code multiple decisions in Python

2 Answers2