django中ajax post请求期间的HttpResponse错误

Question

Friends, I am trying to handle form submission using ajax in django. I've been getting this error which says,

The view auths.change_profile.change_username didn't return an HttpResponse object. It returned None instead.

Here's my change_profile.py

def change_username(request):
    if request.is_ajax() and request.method == 'GET':
        return render(request,"auths/edits/edit_username.html",{})
    elif request.method == 'POST' and request.is_ajax():
        username = request.POST['username']
        user = User.objects.get(username=request.user.username)
        user.username = username
        user.save()
        if user.save():
            data = "Username successfully updated"
        else:
            data = "Something went wrong!"
        return HttpResponse(json.dumps({'data':data}), content_type="application/json")

and my ajax.js is as follows

$(document).ready(
    $('#username_form').submit(function(){
    $.ajax({
        type:"POST",
        url:'/change_username/',
        data:{
                'csrfmiddlewaretoken':$('input[name=csrfmiddlewaretoken]').val()
        },
        success:function(data){
            $('#username').html(data);
        }
    });
});
);

Where am I going wrong?

Answer 1

Remove this

if request.is_ajax():
    return render(request,"auths/edits/edit_username.html",{})

You don't need it, as technically your Ajax request will also be of POST or GET type. So all you need is:

if request.method == 'POST':
    username = request.POST['username']
    user = User.objects.get(username=request.user.username)
    user.username = username
    user.save()
    if user.save():
        data = "Username successfully updated"
    else:
        data = "Something went wrong!"
    return HttpResponse(json.dumps({'data':data}))
else:
    json.dumps({"nothing to see": "this isn't happening"})

Answer 2

Try doing this:

from django.http import JsonResponse

def change_username(request):
    if request.is_ajax() and request.method == 'GET':
        return render(request, "auths/edits/edit_username.html", {})
    elif request.is_ajax() and request.method == 'POST':
        username = request.POST['username']
        user = User.objects.get(username=request.user.username)
        user.username = username
        user.save()
        if user.save():
            data = "Username successfully updated"
        else:
            data = "Something went wrong!"
        return JsonResponse({'data': data})

Post Django 1.7, using JsonResponse is the recommended format. Pre 1.7 was the method you originally used.

Let me know if that works.

Edit (attempt 2):

from django.http import JsonResponse
from django.shortcuts import get_object_or_404
from django.views.decorators.http import require_http_methods


@require_http_methods(['POST'])
def change_username(request):
    if not request.is_ajax():
        return render(request, "auths/edits/edit_username.html", {})
    else:
        new_username = request.POST.get('username')
        user = get_object_or_404(User, id=request.user.id)
        initial_username = user.username
        user.username = new_username
        user.save()

        data = {}

        if user.username == new_username:
            data['data'] = "Username successfully updated!"
        else:
            data['data'] = "Something went wrong!"

        return JsonResponse(data)