GET/POST Operation in Django Framework

CURD Operation in Django

Creating a Django application that handles POST requests from a form containing a dropdown list involves several steps:

1. Define the Model (if applicable):

If the dropdown choices are dynamic and come from a database, define a Django model to represent these choices.

Python

# myapp/models.py
from django.db import models

class Category(models.Model):
    name = models.CharField(max_length=100)

    def __str__(self):
        return self.name

2. Create the Form:

Define a Django Form or ModelForm to handle the dropdown field and other form elements.

Python

# myapp/forms.py
from django import forms
from .models import Category # If using a model for dropdown choices

class MyForm(forms.Form):
    # For static choices
    FRUIT_CHOICES = [
        ('apple', 'Apple'),
        ('banana', 'Banana'),
        ('orange', 'Orange'),
    ]
    selected_fruit = forms.ChoiceField(choices=FRUIT_CHOICES, label="Select a Fruit")

    # For dynamic choices from a model
    selected_category = forms.ModelChoiceField(queryset=Category.objects.all(), label="Select a Category")

3. Define the View:

The view handles both GET and POST requests.

Python

# myapp/views.py
from django.shortcuts import render
from .forms import MyForm

def my_view(request):
    if request.method == 'POST':
        form = MyForm(request.POST)
        if form.is_valid():
            # Process the submitted data
            selected_fruit = form.cleaned_data['selected_fruit']
            selected_category = form.cleaned_data['selected_category'] # If using ModelChoiceField
            # Perform actions based on selected values
            return render(request, 'myapp/success.html', {'fruit': selected_fruit, 'category': selected_category})
    else:
        form = MyForm()
    return render(request, 'myapp/my_template.html', {'form': form})

4. Create the Template:

The HTML template displays the form with the dropdown and handles form submission.

Code

<!-- myapp/my_template.html -->
<form method="post">
    {% csrf_token %}
    {{ form.as_p }}
    <button type="submit">Submit</button>
</form>

5. Configure URLs:

Map the view to a URL in your urls.py.

Python

# myproject/urls.py or myapp/urls.py
from django.urls import path
from . import views

urlpatterns = [
    path('my-form/', views.my_view, name='my_form'),
]

Explanation:

• GET Request:
• When the page is initially loaded (a GET request), an empty MyForm instance is created and passed to the template for rendering.
• POST Request:
• When the form is submitted (a POST request), a MyForm instance is created with the request.POST data.
• Form Validation: 
•   form.is_valid() checks if the submitted data meets the form's validation rules.
• Accessing Data: 
•   If the form is valid,  form.cleaned_data provides a dictionary of validated form data, including the selected value from the dropdown.
• Processing Data: 
•  The selected value can then be used to perform further actions, such as filtering database queries or displaying specific content.