How to render a piece of data stored in an external model without refreshing the page?

Question

I am trying to display a User's name on top of a box where they enter their Employee # in a form, without having to refresh the page.

For example, they enter their # and then after they click/tab onto the next field, it renders their name on top, which comes from the database, so the user knows they've entered the correct info. This name is stored in a separate model, so I try to retrieve it using the "id/number".

I am not too familiar with AJAX but after reading a few similar questions it seems like an AJAX request would be the most appropriate way to achieve this. I tried to make a function get_employee_name that returns the name of the person based on the way I saw another ajax request worked, but I'm not sure how to implement this so it displays after the # is entered.

models.py

class EmployeeWorkAreaLog(TimeStampedModel, SoftDeleteModel, models.Model):
    employee_number = models.ForeignKey(Salesman, on_delete=models.SET_NULL, help_text="Employee #", null=True, blank=False)
    work_area = models.ForeignKey(WorkArea, on_delete=models.SET_NULL, null=True, blank=False)
    station_number = models.ForeignKey(StationNumber, on_delete=models.SET_NULL, null=True,  blank=True)

    def __str__(self):
        return self.employee_number

This is the model where the name is stored

alldata/models.py

class Salesman(models.Model):
    slsmn_name = models.CharField(max_length=25)
    id = models.IntegerField(db_column='number', primary_key=True)

I was reading I can add to the "attrs" in the widget an 'onchange' part, but I am not too familiar with how to approach this and tying it to the ajax request from forms and not the html.

forms.py

class WarehouseForm(AppsModelForm):
    class Meta:
        model = EmployeeWorkAreaLog
        widgets = {
            'employee_number': ForeignKeyRawIdWidget(EmployeeWorkAreaLog._meta.get_field('employee_number').remote_field, site, attrs={'id':'employee_number_field'}),
        }
        fields = ('employee_number', 'work_area', 'station_number')

views.py

class EnterExitArea(CreateView):
    model = EmployeeWorkAreaLog
    template_name = "operations/enter_exit_area.html"
    form_class = WarehouseForm

    def form_valid(self, form):
        # do submission stuff..


def get_employee_name(request, id):
    employee = get_object_or_404(Salesman, id=id)
    return HttpResponse(employee.slsmn_name)

urls.py

urlpatterns = [
    url(r'enter-exit-area/$', EnterExitArea.as_view(), name='enter_exit_area'),

    path('get-employee-name/<int:id>/', views.get_employee_name, name='ajax_get_employee_name'),
]

The ajax request I tried to create is at the end of this html. I modified a similar request I found, but it does not actually display anything on the screen, not sure if I'm missing an area where the request is actually never being called, as I am not too familiar with how these types of requests work.

enter_exit_area.html

{% extends "base.html" %}

{% block main %}
    <form id="warehouseForm" action="" method="POST" novalidate >
        {% csrf_token %}
        <div>
            <h1 id="url" get-employee-name-url="{% url 'operations:ajax_get_employee_name' %}">{{ employee_name }}</h1>
            <div>
                {{ form.employee_number.help_text }}
                {{ form.employee_number }}
            </div>
            <div>
                {{ form.work_area.help_text }}
                {{ form.work_area }}
            </div>
        </div>

        <div>
            <div>
                <button type="submit" name="enter_area" value="Enter">Enter Area</button>
            </div>
        </div>
    </form>

    <script>
        $("#id_employee_number").change(function () {
            var employee_number = $(this).val();
            var url = '/enter-exit-area/get-employee-name/' + employee_number;

            $.ajax({
            url: url,
            type:'GET',
            data: {
                'id': employee_number
            },
            success: function (data) {
                var employee_name = data['employee_name'];
                $('#employee_name')[0].innerHTML = employee_name;
            },
            error : function (data) {
                var error_message = data['error'];
                $('#employee_name')[0].innerHTML = error_message;
            }
            });
        });
    </script>

{% endblock main %}

What could be causing nothing to render on the page? I assume there needs to be a place where the onchange() goes, but I'm not sure where this would be in since the form fields are it's own thing, without tags.

Answer 1

Since you're defining you endpoint in the urlpatterns[] as follows:

path('get-employee-name/<int:id>/', views.get_employee_name, name='employee_name'),

the associated view should expect id a second parameter following request ; for example:

from django.http import HttpResponse
from django.shortcuts import get_object_or_404


def get_employee_name(request, id):
    employee = get_object_or_404(Salesman, id=id)
    return HttpResponse(employee.slsmn_name)

In the ajax call, I would rather use an absolute url:

var url = '/get-employee-name/' + employee_number;

(please note the leading backslash) otherwise, the visited url would be relative to the current page; If the app's urlpatterns in included in the root one with a suffix, add it as required:

var url = '/the_app/get-employee-name/' + employee_number;

Also, you don't need 'data' in the ajax call parameters, since you're expecting the employee_number from the url.

Finally, I would add:

console.log('data: %o', data)

to the success callback to make sure you're receiving what you expect