Show loading gif until the django view performs the data processing and renders the template with this data - django

Question

I have a django project where the page has multiple nav links representing different agents. On clicking any nav link, the urls.py redirects to nav specific view and the view needs to perform some processing to get the data needed to render the template. However as this is syncrhonous rendering it takes a long while to load data (in the order of 15-20s).
Below is my urls.py:
from django.urls import path
from . import views
app_name = 'agent'
urlpatterns = [
path('agent1/', views.agent1, name='agent1'),
path('agent2/', views.agent2, name='agent2'),
path('agent3/', views.agent3, name='agent3'),
path('agent4/', views.agent4, name='agent4'),
]
My views method looks as below:
def agent1(request):
agent_data = Agent1.objects.all()
agent_details = get_agent_details(agent_data)
return render(request, 'manager/data.html', {'agent_data': agent_data, 'agent_details': agent_details})
I am using the {{ agent_data.name }}, {{ agent_data.code }}, {{ agent_data.qty }} and {{ agent_data.price }} along with data from agent_details dictionary in my html to populate a table's rows. How should I change my view method, so that it loads the data via AJAX (javascript) in order to show a loading gif in the meantime and also provide me the data so that I can populate the table. Could someone help me with the Ajax code and the steps as I am new to this technology and not finding any help going through the online tutorials.

Answer 1

So for this to work with ajax, you'll need some javascript in manager/data.html which knows the url to fetch data from.
As an example, I've got an ajax setup which checks a given email address isn't already in use;
(function($) {
$(document).ready(function() {
var validateEmailURL = $section_user_signup.data('ajax-email-url');
function validateEmailUnique() {
var valid = true;
clearError($email);
// Fetch unique status of the provided email
$.ajax({
async: false,
url: validateEmailURL,
method: 'POST',
type: 'POST',
dataType: 'json',
data: {
'email': $email.val(),
'csrftoken': $form.find('input[name="csrfmiddlewaretoken"]').val()
},
success: function (response) {
valid = true;
},
error: function (response) {
setError($email, response["responseJSON"]["error"]);
valid = false;
}
});
return valid;
}
});
})(window.jQuery);
This javascript uses the data attribute of a div for the URL to check;
<div data-ajax-email-url="{% url 'account_ajax_validate_email' %}">
The view which the ajax call goes to looks like this;
def ajax_check_email_unique(request, *args, **kwargs):
"""
Return an JsonResponse to identify if an email is unique.
"""
if not request.is_ajax():
return HttpResponseBadRequest()
if request.is_ajax and request.method == "POST":
email = request.POST.get('email')
if email_address_exists(email):
return JsonResponse(
{
"error":
"Email address already exists. Click "
f"here "
"to login"
},
status=400
)
return JsonResponse(
{"email": email},
status=200
)
# some error occurred
return JsonResponse({"error": ""}, status=400)
The important thing for any view which will be used by javascript is that you return a JsonResponse.
So if I was you, I'd setup a new view for ajax, and that makes your existing one really simple;
def agent1_ajax(request):
agent_data = Agent1.objects.all()
agent_details = get_agent_details(agent_data)
return JsonResponse({
"agent_data": agent_data, "agent_details": agent_details
}, status=200)
def agent1(request):
return render(request, 'manager/data.html', {})
And as far as a loading gif goes, you'd need an element that contains the gif and then you can bind to the ajax event to show/hide;
$(document).ajaxStart(function() {
$("#loading").show();
});
$(document).ajaxStop(function() {
$("#loading").hide();
});