Making of Django REST Project

Use the Django CRUD Project for initial files and settings.
Create another app "fscohort_api" + add to settings.py INSTALLED_APPS + create fscohort_api > urls.py file + include fscohort_api to main urls.py
Import JsonResponse from django.http in fscohort_api > views
Create a func named home_api in views and add a dictionary structured static data in. We will soon change it to dynamic.
Import home_api to urls and define a path
Run server + check the path http://localhost:8000/api/home-api/ see the json file
Open "Postman" use the same url + GET. Make sure you see the same json file
Import student from models to fscohort_api > views. Two methods for displaying data in database (as objecs) in json form:

def student_list_api(request):
    if request.method == "GET":
        students = Student.objects.all()
        student_count = Student.objects.count()

        student_list = []
        for student in students:
            student_list.append({
                'first_name': student.first_name,
                'last_name': student.last_name,
                'number': student.number
            })

    data = {
        "students": student_list,
        "count": student_count
    }
    return JsonResponse(data)

Use serializer. from django.views.decorators.csrf import csrf_exempt

def student_list_api(request):
    if request.method == "GET":
        students = Student.objects.all()
        student_count = Student.objects.count()
        student_data = serialize("python", students)

        data = {
            "students": student_data,
            "count": student_count
        }

    return JsonResponse(data)

Now we want to do the opposite. We want the transform the json data sent from backend to dictionary form in order to save to database. import json. This is for converting json to dict.

@csrf_exempt
def student_create_api(request):
    if request.method == "POST":
        post_body = json.loads(request.body)
        print(type(post_body))  # <class 'dict'>
        name = post_body.get("first_name")
        last_name = post_body.get("last_name")
        number = post_body.get("number")

        student_data = {
            "first_name": name,
            "last_name": last_name,
            "number": number
        }

        student_obj = Student.objects.create(**student_data)
        data = {
            "message": f"Student {student_obj.first_name} created successfully"
        }
        return JsonResponse(data, status=201)

Since we do not have a frontend at the moment, we use POSTMAN to send json data. (POST-Body-raw).

{
    "first_name": "Eric",
    "last_name": "Emerson",
    "number": 5
}

To get rid of csrf error add from django.views.decorators.csrf import csrf_exempt and also add @csrf_exempt before function. We could have not used name, last_name and number variables and student_data as well + student_obj = Student.objects.create(**post_data) instead, because the data in body is exactly the same as we have in db. But otherwise we have to define the data structure.

Install rest_framework python3 -m pip install djangorestframework and add rest_framework to INSTALLED_APPS in settings.py
Django REST helps us automatically serialize data, so that we do not have to write long line of codes.
Create serializers.py under fscohort_api, import Student model and create a class as below

from rest_framework import serializers
from fscohort.models import Student


class StudentSerializer(serializers.ModelSerializer):
    class Meta:
        model = Student
        fields = ["first_name", "last_name", "number"]

Note that this is very similar to a form.

Now go to views and comment out all functions except home_api. Import the following

from rest_framework.response import Response
from rest_framework.decorators import api_view
from .serializers import StudentSerializer
from rest_framework import status

Add this function:

@api_view(["GET", "POST"])
def student_list_create_api(request):
    if request.method == "GET":
        students = Student.objects.all()
        serializer = StudentSerializer(students, many=True)
        # many=True because we get many objects
        return Response(serializer.data) #.data is default
    elif request.method == "POST":
        serializer = StudentSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            data = {
                "message": "Student created successfully"
            }
            return Response(data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

Remove the commented out imported functions in urls and import student_list_create_api + add the path
Check if you see djangos fantasic page on http://localhost:8000/api/list-create-api/
Check also from POSTMAN with the same url both with GET and POST. If you get "Unsupported media type" error with POST, go to Headers and add Content-Type under KEY column and application/json under VALUE column. Then try again.
Up to here we were getting into the logic. There are other ways to get the same functional results : Class Based Views, Generic Views and Mixin Views. These can replace each other.

SemihDurmus/Django_REST

Making of Django REST Project