Full Stack Build Part 1 - Building and Deploying an API

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What you will learn

• Creating an API
• Setting Cors Headers
• Testing an API
• Deploying an API

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Setup

• Open up terminal in your django folder

• activate your virtual environment source ./djangoenv/bin/activate

• generate a new django project django-admin startproject todoproject

• cd into the todoproject folder

• test your dev server python manage.py runserver

Creating the API

• create a new app django-admin startapp todos

DjangoRestFramework

When creating an API previously we did without any external help and making basic crud routes ended being a bit tedious...

• write all crud functions individually

• we had to convert our data to json then back to a dictionary to send back as json

• the shape of the data isn't we would traditionally would expect

• we had to turn off CSRF security and other security features to make work

DjangoRestFramework fixes all the above and creates a nice abstraction for creating REST API's with django. Let's do it!

DJANGO REST FRAMEWORK DOCUMENTATION

• install djangorestframework pip install djangorestframework

• install djangorestframework and the todos app in settings.py

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'todos.apps.TodosConfig',
    'rest_framework'
]

Creating our Model

todos/models.py

from django.db import models

class Todo(models.Model):
    subject = models.CharField(max_length=100)
    details = models.CharField(max_length=100)

Make and Run Migrations

• python manage.py makemigrations
• python manage.py migrate

Making Our Serializer

Serializing objects into json strings and then turning them back into python dictionaries can be a tedious process. With djangorestframework, we can build a serializer for our model that handles all this for us along with arranging the data in a more traditional form.

• create a serializers.py in our todos app

from .models import Todo
from django.contrib.auth.models import User, Group
from rest_framework import serializers

# Our TodoSerializer
class TodoSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        # The model it will serialize
        model = Todo
        # the fields that should be included in the serialized output
        fields = ['id', 'subject', 'details']

Creating Our Viewset

djangorestframework has classes for building out views called ViewSets. With these we can wire up all our CRUD routes pretty easily.

in todos/views.py

from .models import Todo
from rest_framework import viewsets
from rest_framework import permissions
from .serializers import TodoSerializer


class TodoViewSet(viewsets.ModelViewSet):
    ## The Main Query for the index route
    queryset = Todo.objects.all()
    # The serializer class for serializing output
    serializer_class = TodoSerializer
    # optional permission class set permission level
    permission_classes = [permissions.AllowAny] #Coule be [permissions.IsAuthenticated]

Setting Up Our Router

To make sure all of the ViewSets methods connects to the rights urls, djangorestframework provides with a router to wire it all up. Let's head over to our urls.py.

from django.contrib import admin
from django.urls import path, include
from rest_framework import routers
from todos.views import TodoViewSet

# create a new router
router = routers.DefaultRouter()
# register our viewsets
router.register(r'todos', TodoViewSet) #register "/todos" routes


urlpatterns = [
    # add all of our router urls
    path('', include(router.urls)),
    path('admin/', admin.site.urls),
]

Testing the API

• fire up postman

• create 3-4 todos with post requests to /todos/

• get the full list with a get request to /todos/

• see one todo with a get request to /todos/<id>

• edit a todo with a put request to /todos/<id>

• delete a todo with delete request to /todos/<id>

Deploying the API

Now it's time to deploy the API, so first we have setup to do...

• install the libraries we need... pip install django-heroku gunicorn django-cors-headers

  • gunicorn: web server to run in production

  • django-heroku: configures our app for heroku deployment

  • django-cors-headers: will be used to handle cors

    If you have any issues with installing psychopg2 (django-heroku dep), it is either cause you don't have x-code installed on mac or on linux you need to install "libpq-dev", on ubuntu based systems the command would be sudo apt-get install libpq-dev

setting up django-heroku

In settings.py

• at the top import django-heroku import django_heroku

• at the bottom add django_heroku.settings(locals())

setting up django-cors-headers

In settings.py

• install the django-cors-headers app

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

• add the cors middleware

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

• after the middleware section add this line to allow all origins

CORS_ALLOW_ALL_ORIGINS = True ## <---- will allow all origins, read cors docs to limit

Additional Setup

• create a file called Procfile in the root of your project (where manage.py is)

web: gunicorn todoproject.wsgi

• add a runtime.txt in the project root with your python version

python-3.9.0

• generate a list of dependencies in requirements.txt with the command pip freeze > requirements.txt make sure to redo this anytime you add new dependencies

Getting it to heroku

• create a git repo in the root, commit, then push up to github.com repo

• create a new heroku project, connect your git repo to it, deploy

• run python manage.py migrate from the heroku dashboard or the heroku cli

• test you newly deployed api in postman.

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Resources to Learn More

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