[ In Django registration, if username already exists do something ]

this is a very basic and quick question in Django.

So in my views, where I am handling the registration, if a user tries to register with a username that already exists I want to just give a message, like a span next to the form, saying, "wrong username".

How do I print that message?

Thank you.

This is my part of code:

def register(request):
 if request.method == 'POST':
  if User.objects.filter(username = request.POST['username']).exists():
   #I want to show next to the username textfield in registration form,
   #a span for example that says "Wrong Username"

Answer 1

As suggested in a comment above, you should do it in form's clean method which would make things easier. But if you must do it in a view, here's an example:

if request.method == 'POST':
    try:
        user_exists = User.objects.get(username=request.POST['username'])
        return HttpResponse("Username already taken")
    except User.DoesNotExist:
        # Username doesn't exist
        # Do other validation ...

Then show the response in a span using jQuery, or something else.

Answer 2

To get HTTPResponse message, you have to use ajax instead form submit.

Here i am assuming you are using following like html page code.

<input type="text" name="username" id="username"/>  <p id="error"></p>

<input type="button" value="Register" id="register">

Now, You have to make an ajax call on button's click event like:

(i assume that you have knowledge of ajax call.)

$("#register").on('click', function(){

var username=$("#username").val();

    $.ajax({
    .
    .
    .
    success: fuinction(data){
        if(data=="error occured"){
           $("error").append("wrong username");
    }
    }

    })

    });

and views.py code is like this:

def register(request):
 if request.method == 'POST':
  if User.objects.filter(username = request.POST['username']).exists():
    return HTTPResponse("error occured")