Python Django + SQLite REST APIs

In this post we will see how to create CRUD APIs using Python Django as backend and SQLite for database.

Lets install the necessary modules needed for our Django project.

First lets install the Django module.

>> pip install django

To create rest APIs we need to install Django rest framework.

>> pip install djangorestframework

By default, the Django project comes with a security that blocks requests coming from different domains. To disable this, lets install Django CORS headers module.

>> pip install django-cors-headers

Now lets create the Django project.

Open the command prompt in the desired folder and type the command.

>> django-admin start project <name of the project>

Lets take a look at some of the important files in the project.

 

>> __init__.py file is just and empty file that indicates that the given folder is a python project or a python module.

>>  asgi.py is the entry point for the asgi compatible webservers.

>> wsgi.py is the entry point for the wsgi compatible web servers.

>> urls.py file contains all the url declarations needed for this project.

>> settings.py file contains all the settings or the configurations needed for the project.

>> manage.py is a command line utility that helps interact with the Django project.

 

Lets simply run the project and see how it looks in the browser using below command.

>> python manage.py runserver

The app is now running in the port 8000.

Lets copy  the url and open in the browser.

What you see on the screen is the default template that comes with every Django project.

 

 

Now lets create an app in our Django project.

Quick difference between projects and apps.

The folder structure that you currently see on the screen is called the project.

A project may have multiple apps.

For example, you can have one app which acts like a blog, or may be another app which acts like a survey form.

Currently this project does not have any app.

Lets create one app to implement our api methods.

To create an app, we need to type this command.

>> python manage.py startapp <the name of the app>

Next let us register the app and the required modules in settings.py file.

In the installed apps section, lets add Rest framework, cors header, and the newly created app.

We need to add the cors headers in middle ware section as well.

We will also add instruction to enable all domains to access the APIs.

This is not recommended in production. Instead, just add only those domains that needs to be whitelisted.

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'rest_framework',
    'corsheaders',
    'EmployeeApp.apps.EmployeeappConfig'
]

CORS_ORIGIN_ALLOW_ALL = True

MIDDLEWARE = [
    'corsheaders.middleware.CorsMiddleware',
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

 

Lets create the models needed for our app.

We need two models.

One to store department details and another one to store employee details.

The departments model will have two fields. One to store an autoincremented Department ID, and another one to store Department Name.

Employee model will have five fields.

Employee ID, Employee name, Department, Date of joining, and photo file name which stores the uploaded profile picture file name.

Models.py complete code:

from django.db import models

# Create your models here.

class Departments(models.Model):
    DepartmentId = models.AutoField(primary_key=True)
    DepartmentName = models.CharField(max_length=500)

class Employees(models.Model):
    EmployeeId = models.AutoField(primary_key=True)
    EmployeeName = models.CharField(max_length=500)
    Department = models.CharField(max_length=500)
    DateOfJoining = models.DateField()
    PhotoFileName = models.CharField(max_length=500)

We will be using the default SQLite database that comes with our Django project.

We can see that it is already registered in the database section of settings.py file.

Lets write the command to make migrations file for our models.

>> python manage.py makemigrations <app name>

After executing this, we can see a migration file which tells us what changes to the database will be done.

Once it looks fine, we can execute the command to push these changes to the database.

>> python manage.py migrate <app name>

Lets create serializers for our models.

Serializers basically help to convert the complex types or model instances into native python data types that can then be easily rendered into json or xml or other content types.

They also help in deserialization which is nothing but converting the passed data back to complex types.

 serializers.py complete code:

from rest_framework import serializers
from EmployeeApp.models import Departments,Employees

class DepartmentSerializer(serializers.ModelSerializer):
    class Meta:
        model=Departments 
        fields=('DepartmentId','DepartmentName')

class EmployeeSerializer(serializers.ModelSerializer):
    class Meta:
        model=Employees 
        fields=('EmployeeId','EmployeeName','Department','DateOfJoining','PhotoFileName')

Lets now start writing the API methods.

views.py code.

from django.shortcuts import render
from django.views.decorators.csrf import csrf_exempt
from rest_framework.parsers import JSONParser
from django.http.response import JsonResponse

from EmployeeApp.models import Departments,Employees
from EmployeeApp.serializers import DepartmentSerializer,EmployeeSerializer

from django.core.files.storage import default_storage

# Create your views here.

@csrf_exempt
def departmentApi(request,id=0):
    if request.method=='GET':
        departments = Departments.objects.all()
        departments_serializer=DepartmentSerializer(departments,many=True)
        return JsonResponse(departments_serializer.data,safe=False)
    elif request.method=='POST':
        department_data=JSONParser().parse(request)
        departments_serializer=DepartmentSerializer(data=department_data)
        if departments_serializer.is_valid():
            departments_serializer.save()
            return JsonResponse("Added Successfully",safe=False)
        return JsonResponse("Failed to Add",safe=False)
    elif request.method=='PUT':
        department_data=JSONParser().parse(request)
        department=Departments.objects.get(DepartmentId=department_data['DepartmentId'])
        departments_serializer=DepartmentSerializer(department,data=department_data)
        if departments_serializer.is_valid():
            departments_serializer.save()
            return JsonResponse("Updated Successfully",safe=False)
        return JsonResponse("Failed to Update")
    elif request.method=='DELETE':
        department=Departments.objects.get(DepartmentId=id)
        department.delete()
        return JsonResponse("Deleted Successfully",safe=False)

@csrf_exempt
def employeeApi(request,id=0):
    if request.method=='GET':
        employees = Employees.objects.all()
        employees_serializer=EmployeeSerializer(employees,many=True)
        return JsonResponse(employees_serializer.data,safe=False)
    elif request.method=='POST':
        employee_data=JSONParser().parse(request)
        employees_serializer=EmployeeSerializer(data=employee_data)
        if employees_serializer.is_valid():
            employees_serializer.save()
            return JsonResponse("Added Successfully",safe=False)
        return JsonResponse("Failed to Add",safe=False)
    elif request.method=='PUT':
        employee_data=JSONParser().parse(request)
        employee=Employees.objects.get(EmployeeId=employee_data['EmployeeId'])
        employees_serializer=EmployeeSerializer(employee,data=employee_data)
        if employees_serializer.is_valid():
            employees_serializer.save()
            return JsonResponse("Updated Successfully",safe=False)
        return JsonResponse("Failed to Update")
    elif request.method=='DELETE':
        employee=Employees.objects.get(EmployeeId=id)
        employee.delete()
        return JsonResponse("Deleted Successfully",safe=False)

@csrf_exempt
def SaveFile(request):
    file=request.FILES['file']
    file_name=default_storage.save(file.name,file)
    return JsonResponse(file_name,safe=False)

For Save File API, create a folder with name 'Photos':

settings.py complete code:

"""
Django settings for DjangoAPI project.

Generated by 'django-admin startproject' using Django 3.2.4.

For more information on this file, see
https://docs.djangoproject.com/en/3.2/topics/settings/

For the full list of settings and their values, see
https://docs.djangoproject.com/en/3.2/ref/settings/
"""

from pathlib import Path
import os

BASE_DIR=Path(__file__).resolve(strict=True).parent.parent
MEDIA_URL='/Photos/'
MEDIA_ROOT=os.path.join(BASE_DIR,"Photos")


# Build paths inside the project like this: BASE_DIR / 'subdir'.
BASE_DIR = Path(__file__).resolve().parent.parent


# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/3.2/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = 'django-insecure-@oxx-o(4f=mxha%-tlv97)x9m7x_fw=(@*k=*29q%r7c8*)%-&'

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True

ALLOWED_HOSTS = []


# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'rest_framework',
    'corsheaders',
    'EmployeeApp.apps.EmployeeappConfig'
]

CORS_ORIGIN_ALLOW_ALL = True

MIDDLEWARE = [
    'corsheaders.middleware.CorsMiddleware',
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'DjangoAPI.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

WSGI_APPLICATION = 'DjangoAPI.wsgi.application'


# Database
# https://docs.djangoproject.com/en/3.2/ref/settings/#databases

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': BASE_DIR / 'db.sqlite3',
    }
}


# Password validation
# https://docs.djangoproject.com/en/3.2/ref/settings/#auth-password-validators

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]


# Internationalization
# https://docs.djangoproject.com/en/3.2/topics/i18n/

LANGUAGE_CODE = 'en-us'

TIME_ZONE = 'UTC'

USE_I18N = True

USE_L10N = True

USE_TZ = True


# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/3.2/howto/static-files/

STATIC_URL = '/static/'

# Default primary key field type
# https://docs.djangoproject.com/en/3.2/ref/settings/#default-auto-field

DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

EmployeeApp's urls.py:

from django.conf.urls import url
from EmployeeApp import views

from django.conf.urls.static import static
from django.conf import settings

urlpatterns=[
    url(r'^department$',views.departmentApi),
    url(r'^department/([0-9]+)$',views.departmentApi),

    url(r'^employee$',views.employeeApi),
    url(r'^employee/([0-9]+)$',views.employeeApi),

    url(r'^employee/savefile',views.SaveFile)
]+static(settings.MEDIA_URL,document_root=settings.MEDIA_ROOT)

Main urls.py:

"""DjangoAPI URL Configuration

The `urlpatterns` list routes URLs to views. For more information please see:
    https://docs.djangoproject.com/en/3.2/topics/http/urls/
Examples:
Function views
    1. Add an import:  from my_app import views
    2. Add a URL to urlpatterns:  path('', views.home, name='home')
Class-based views
    1. Add an import:  from other_app.views import Home
    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
Including another URLconf
    1. Import the include() function: from django.urls import include, path
    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
"""
from django.contrib import admin
from django.urls import path

from django.conf.urls import url,include

urlpatterns = [
    path('admin/', admin.site.urls),
    url(r'^',include('EmployeeApp.urls'))
]

Github Link: https://github.com/ArtOfEngineer/PythonDjango-SQLite-VueJS