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Django REST API

What is API ?

An API is a set of programming code that enables data transmission between one software product and another.

For example, suppose you wanted to incorporate a map to your business on your website or display a list of your latest tweets. You can’t directly access Google Maps or Twitter — the code that runs those sites sits on Google and Twitter servers. But those platforms provide APIs that let authorized users retrieve data from their sites.

What is REST API ?

Representational State Transfer (REST) is an architectural style that defines a set of constraints to be used for creating web services. REST API is a way of accessing web services in a simple and flexible way without having any processing. Ref :Click Here

What is Django Rest Framework?

The Django REST Framework (DRF) is a package built on top of Django to create web APIs. One of the most remarkable features of Django is its Object Relational Mapper (ORM) which facilitates interaction with the database in a Pythonic way.

However, we can not send Python objects over a network, and hence need a mechanism to translate Django models in other formats like JSON, XML, and vice-versa. This sometimes challenging process, also called serialization, is made super easy with the Django REST Framework.

Getting Started with Django Rest Framework

First, we create the model simple model of Students to represent the student details.

  • Add below Students model in _/myworld/members/model.py_ file 
    from django.db import models

BRANCH_CHOICES = (
    ("BA", "BA"),
    ("B.COM", "B.COM"),
    ("MBA", "MBA"),
    ("CA", "CA"),
)

# Create your models here.
class Students(models.Model):
    first_name = models.CharField(max_length=200)
    last_name = models.CharField(max_length=200)
    address = models.CharField(max_length=200)
    roll_number = models.IntegerField()
    mobile = models.CharField(max_length=10)
    branch = models.CharField(max_length=10, choices=BRANCH_CHOICES)

    def __str__(self):
        return self.first_name + " " + self.last_name
    choices: Click here

We created our model and we will register this model with Django.

  • To visible this into the admin panel, we will add the following line in the _/myworld/members/admin.py_. 
    from django.contrib import admin
from .models import Students

class DjStudentAdmin(admin.ModelAdmin):
    list_display = ("first_name", "last_name", "address", "roll_number", "mobile", "branch")
    list_filter = ("branch",)

# Register your models here.
admin.site.register(Students, DjStudentAdmin)

Our new model is registered. We will need to makemigration to reflect the Student table into the database.

  • Run the following commands inside workshop_web_container.
    • Login to the container 
      docker exec -it workshop_web_container sh
    • Run make Migration 
      python3 manage.py makemigrations  
python3 manage.py migrate

Add entries to Student model

  • Open this like http://0.0.0.0:8000/admin/ and login to admin site if not.
  • Click on Students model.
  • Click on ADD STUDENT on top right corner of the admin page to add new students.
  • Fill all tge field and click save button Note : Add atleast 10 student information.

Create Views

DRF allows us to create both class-based and function-based views for the API. We will create the class-based view. We will use Django's View class. We can define the get(), post() methods so that we can perform the CRUD operations.

  • as_view(): as_view() class method which returns a function that can be called when a request arrives for a URL matching the associated pattern.
  • class-based views : Click here
  • Add below code to _/myworld/members/views.py_. 
    from django.views import View
from .models import Students
from django.http import JsonResponse
from django.views.decorators.csrf import csrf_exempt
from django.utils.decorators import method_decorator


@method_decorator(csrf_exempt, name='dispatch')
class StudentView(View):

def get(self, request, rolno=None, branch=None):
    student_model_list = []
    try:
        if rolno:
            student_model_list = Students.objects.filter(roll_number=rolno)
        elif branch:
            student_model_list = Students.objects.filter(branch=branch)
    except Students.DoesNotExist:
        return JsonResponse({'status': 'failed', "students": None}, status=400)
    students = []
    for student in student_model_list:
        data = {
            "first_name" : student.first_name,
            "last_name": student.last_name,
            "address": student.address,
            "roll_number": student.roll_number,
            "mobile": student.mobile,
            "branch": student.branch
        }
        students.append(data)
    return JsonResponse({'status': 'success', "students": students}, status=200)

def post(self, request):
    if not request.POST.get('first_name') or not request.POST.get('last_name') or not request.POST.get('address') or  not request.POST.get('roll_number') or not request.POST.get('mobile'):
        return JsonResponse({'status': 'failed', "message" : "all fields required"}, status=500)

    Students.objects.create(
        first_name= request.POST.get('first_name'),
        last_name= request.POST.get('last_name'),
        address= request.POST.get('address'),
        roll_number= request.POST.get('roll_number'),
        mobile= request.POST.get('mobile'),
        branch= request.POST.get('branch'))
    return JsonResponse({'status': 'sucess'}, status=200)
    • Here in post() method we create new student object and in get() method we return studnet information in json formate

Setup Endpoints for View

  • Add below code in _/myworld/members/urls.py_. 
    from django.urls import path
from . import views

urlpatterns = [
    path('rest/student/<int:rolno>', views.StudentView.as_view()),
    path('rest/student/', views.StudentView.as_view()),
    path('rest/student/<str:branch>', views.StudentView.as_view()),
]

Trigger API using curl

CURL : CURL, which stands for client URL, is a command line tool that developers use to transfer data to and from a server.

  • GET Request to get student information
    • Syntax 
      curl -X GET http://0.0.0.0:8000/members/rest/student/<roll number>
    • Curl cmd 
      curl -X GET http://0.0.0.0:8000/members/rest/student/1
curl -X GET http://0.0.0.0:8000/members/rest/student/CA
    Note : Try with wrong roll number
  • POST request to add new student
    • Syntax 
      curl -X POST http://0.0.0.0:8000/members/rest/student/ -d "first_name=<str>&last_name=<str>&address=<str>&roll_number=<int>&mobile=<str>&branch=<str>"
    • Curl cmd 
       curl -X POST http://0.0.0.0:8000/members/rest/student/ -d "first_name=shamith&last_name=H&address=mk&roll_number=3&mobile=897654354&branch=CA"
    Note : Please check new student is added after running above command.