In Django registration, if username already exists do something

Question

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"

The best way to handle this is in the form's clean method - where you can raise a validation error on the specific field — karthikr
– karthikr, Commented Jan 9, 2015 at 16:22
@karthikr Post an example confirming the statement and post is as an answer. — Igor Pejic
– Igor Pejic, Commented Jan 9, 2015 at 16:34

xyres · Accepted Answer · 2015-01-09 16:38:20Z

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.

answered Jan 9, 2015 at 16:38

xyres

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6 Comments

Nicolas Nicolas Over a year ago

thanks for the answer. That's my actual question. How do I transform the HttpResponse to a span? :D thanks

xyres Over a year ago

@NicolasNicolas Are you doing it with AJAX?

Nicolas Nicolas Over a year ago

Ideally I would want just to show a span in the page that is already loaded. Not re-render a page.

xyres Over a year ago

Well, then you need to use AJAX. This has nothing to do with Django. You need to look into jQuery for that.

Nicolas Nicolas Over a year ago

Thanks for your answer again. I am pretty sure that this is relevant to Django. The solution I had in mind was something like, in the template of the page I am, I put a Django if statement, and inside that I put the span that I want to show IF the username already exists. But I just don't know how to connect these. thanks again

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jatinkumar patel · Accepted Answer · 2015-01-09 18:54:46Z

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")

JaceOn Ogskun · Accepted Answer · 2018-10-18 08:04:37Z

I want to modify an answer from above which can be more easier.... i think :) haha:

def register(request): alert = { "username": request.GET.get('username', ''), } if request.method == 'POST': username = request.POST.get('username', '') if User.objects.filter(username = request.POST['username']).exists(): alert['username'] = "Username already exists" return render(request, 'interface/signup.html', alert)

and in your html: lets just say -->

<form method="POST"> {% csrf_token %} <h3>Sign Up</h3> <label class="label">Username:</label><input type="text" name="username" class="form-control" /><br> {% if username %} <div class="alert alert-danger alert-dismissible"> <a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a> {{ username }} </div> <br> {% endif %} </form>

David Jay Brady · Accepted Answer · 2020-07-11 02:19:37Z

def register(request): form = UserCreationForm(request.POST) if form.is_valid(): else: # Form is invalid, this includes the user already existing

I know it's 2 years late but none of the answers had it and django has a built in way of solving it.

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