Resolving Django Formset Issues with Dynamic Forms
Based on your code and the issues you're experiencing, I can identify solutions for both the CSRF verification failure and the form deletion problem.
CSRF Verification Failed Issue
The CSRF verification failure is likely occurring because:
- Your AJAX request is missing the CSRF token or it's not being properly included
- There's an issue with the syntax in your JavaScript where the CSRF token retrieval is cut off
Here's how to fix it:
// Add this at the beginning of your script
function getCookie(name) {
let cookieValue = null;
if (document.cookie && document.cookie !== '') {
const cookies = document.cookie.split(';');
for (let i = 0; i < cookies.length; i++) {
const cookie = cookies[i].trim();
if (cookie.substring(0, name.length + 1) === (name + '=')) {
cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
break;
}
}
}
return cookieValue;
}
// Then in your AJAX call
$.ajax({
url: '{% url "ajax_load_projects" %}',
data: {
client: Number(selectedClientId),
'csrfmiddlewaretoken': getCookie('csrftoken')
},
// rest of your AJAX code
});
Also, ensure that your form submission includes the CSRF token by:
- Making sure the
{% csrf_token %}
is inside your form (which it is in your code)
- Adding this to your JavaScript to include the token in all AJAX requests:
// Add this at the beginning of your script
const csrftoken = getCookie('csrftoken');
$.ajaxSetup({
beforeSend: function(xhr, settings) {
if (!/^(GET|HEAD|OPTIONS|TRACE)$/i.test(settings.type) && !this.crossDomain) {
xhr.setRequestHeader("X-CSRFToken", csrftoken);
}
}
});
Form Deletion Issue
The issue with forms becoming blank when deleting a form is related to how you're handling form indices. When you delete a form, you need to renumber all subsequent forms to maintain proper order. Your current removeForm
function has a syntax error (an extra closing bracket) and doesn't properly renumber the forms.
Here's an improved version:
function removeForm(formNum) {
let form = document.getElementById(`form-${formNum}`);
form.remove();
// Update the TOTAL_FORMS count
let totalForms = document.querySelector("#id_form-TOTAL_FORMS");
let currentCount = parseInt(totalForms.value);
totalForms.value = currentCount - 1;
// Renumber all forms after the deleted one
let formsContainer = document.querySelector("#user-forms");
let forms = formsContainer.querySelectorAll(".user-form");
for (let i = 0; i < forms.length; i++) {
let currentForm = forms[i];
let currentId = currentForm.id;
let currentIndex = parseInt(currentId.split('-')[1]);
if (currentIndex > formNum) {
// Update form ID
let newIndex = currentIndex - 1;
currentForm.id = `form-${newIndex}`;
// Update all input fields within the form
currentForm.querySelectorAll('[id^=id_form-]').forEach(function(field) {
let oldId = field.getAttribute('id');
let oldName = field.getAttribute('name');
field.setAttribute('id', oldId.replace(/\d+/, newIndex));
field.setAttribute('name', oldName.replace(/\d+/, newIndex));
});
}
}
}
Additional Recommendations
-
Fix the syntax error in your current code:
There's an extra });
at the end of your removeForm
function that's causing issues.
-
Use the Django formset's built-in management form properly:
Django formsets include a management form that handles form counts. Make sure you're not manipulating it incorrectly.
-
Consider using Django's formset factory with can_delete=True
:
This allows Django to handle deletion logic for you:
# In your views.py
from django.forms import formset_factory
YourFormSet = formset_factory(YourForm, extra=1, can_delete=True, max_num=10)
- Set a reasonable
max_num
value:
Django 1.4.4 and later enforce a maximum number of forms (1000 by default) to prevent memory exhaustion attacks. Make sure you're setting an appropriate limit for your use case.
By implementing these changes, you should be able to resolve both the CSRF verification failure and the form deletion issues in your Django formset implementation.