Django Rest Framework:

Django Rest Framework(DRF):

Django Rest Framework(DRF) is an application used to build RESTful API based on Django models.

In a RESTful API, endpoints(URLs) define the structure of API and how end user access data from our application using HTTP methods like GET, POST, PUT, DELETE etc..

 

Requirements:

In my case,

Python 3.8

Django 3.0

·        Create a Django project and app

cd ~

django-admin startproject local-librari-api

cd local-library-api

python manage.py startapp catalogapp

Create and activate virtual environment and install rest framework as fallows 

Installation:

·        Installing with pip:

pip install djangorestframework

djangorestframework==3.11.0

·        Go to Django project -> settings.py and add ‘rest_framework’ to INSTALLED_APPS

INSTALLED_APPS = [

    'catalogapp',

    'rest_framework',

]

 

·        And then create models for the app to work in cataogapp/models.py module

from django.db import models





class Genre(models.Model):

    """Model representing a book genre."""

        

class Book(models.Model):

    """Model representing a book (but not a specific copy of a book)."""

    title = models.CharField(max_length=200)



    author = models.ForeignKey('Author', on_delete=models.SET_NULL)



    summary = models.TextField(max_length=1000)

    isbn = models.CharField(max_length=13,)    

    genre = models.ManyToManyField(Genre)

        language = models.ForeignKey('Language', on_delete=models.SET_NULL)



    def __str__(self):

        """String for representing the Model object."""

        return self.title







class BookInstance(models.Model):

    

    

class Author(models.Model):

    """Model representing an author."""



class Language(models.Model):

etc……

·        Now create initial migrations and sync database as fallows..

 

(venv) C:\Users\local-library-api>python manage.py makemigrations

(venv) C:\Users\local-library-api>python manage.py makemigrations

 

Creating serializer class:

-         In order to work with REST API, we need to convert model objects into some other format like JSON.

-         We can do this by importing serializers module from djangorestframework.

-         Now create a file named serializers.py in catalogapp directory … like catalogapp/serializers.py

from rest_framework import serializers

from catalogapp import Book, Authors





class BookSerializer(serializers.Serializer):

    title = CharField(max_length=200)

    author = PrimaryKeyRelatedField(allow_null=True, queryset=Author.objects.all(), required=False)

    summary = CharField(max_length=1000, style={'base_template': 'textarea.html'})

    isbn = CharField(label='ISBN', max_length=13)

    genre = PrimaryKeyRelatedField(allow_empty=False, many=True, queryset=Genre.objects.all())

    language = PrimaryKeyRelatedField(allow_null=True, queryset=Language.objects.all(), required=False)

Working with API is very similar to Django forms

Using ModelSerializer class:

Django provides both Serializer and ModelSerializer classes

ModelSerializer class automatically determines the model fields and implements the create() and update() methods. This is short-cut for creating serializers for models.

Modify the above code in serializers.py module as fallows…

class BookSerializer(serializers.ModelSerializer):

    class Meta:

        model = Book

        fields = [………. Enter field names here ………..]

with serializer instance, you can see the implementation of serializer…just say

print(repr(serializer instance))

Django views using serializer:

Now write some views using serializer class in catalogapp/views.py module

For example to view all the books in the library

from catalogapp.models import Book

from catalogapp.serializers import BookSerializer

from django.http import JsonResponse

from rest_framework.parsers import JSONParser

def book_list_view(request):

    if request.method == 'GET':

        books = Book.objects.all()

        serializer = BookSerializer(books, many=True)

        return JsonResponse(serializer.data, safe=False)

    elif request.method == 'POST':

        data = JSONParser().parse(request)

        serializer = BookSerializer(data=data)

        if serializer.is_valid():

            serializer.save()

            return JsonResponse(serializer.data, status=201)

        return JsonResponse(serializer.errors, status=400)

 

finally we have to map these view in the catalogapp/urls.py module

urlpatterns = [

    

    path('books/', views.book_list_view, name='books'),



]

 

·        Add the fallowing to root urls.py file…. local-library-api/urls.py

 

urlpatterns = [

    

    path('catalogapp/', include('catalogapp.urls')),

]