sanjay-rb / quickie-flask-restapi-swaggerui-db

Welcome to the Quickie on Flask, REST API, Swagger UI, DB Connection

First Flask App

• Run start_server.bat by passing (app name or module name or project folder) first_flask_app to start the flask server.

> start_server.bat first_flask_app

• Our first_flask_app is a python module which have it's own __init__.py.
• That file is having just few lines of code,

1. import Flask
2. Create Flask App
3. Finally create endpoint using Flask App.

./first_flask_app/__init__.py

# import Flask
from flask import Flask

# Creating flask app instance.
app = Flask(__name__)

# Creatng new endpoint to say "Hello, World!"
@app.route("/")
def hello_world():
    return "Hello, World!"

Let's create simple REST api only using Flask

• We are going to create a CRUD API for simple Link storage app.
• We can store any link in this app.
• Run start_server.bat by passing (app name or module name or project folder) first_flask_app to start the flask server.
• If you see our project folder this time we have routes.py. What is inside that?

./2_simple_rest_api/project/routes.py

from rest_api_basic import app
from flask import jsonify, request
from datetime import datetime

# An empty dictionary to store our links
links = {}

# Read operation in CRUD, ie : R -> CRUD
# Endpoint : http://localhost:5000/link (GET)
# To read & return all links in links dictionary
@app.route('/link', methods=['GET'])
@app.route('/link/', methods=['GET'])
def getAllLink():
    return jsonify(links)

# Create operation in CRUD, ie : C -> CRUD
# Endpoint : http://localhost:5000/link (POST)
# To create or add new link to our links dictionary
@app.route('/link', methods=['POST'])
@app.route('/link/', methods=['POST'])
def addLink():
    data = request.get_json()
    uid = datetime.now().strftime("%Y%M%d%H%M%S%f")
    links[uid] = data
    return jsonify({"message" : "Link added succesfully with id {}".format(uid)})

# Update operation in CRUD, ie : U -> CRUD
# Endpoint : http://localhost:5000/link/20221222221211518239 (PUT)
# To update single link using link's id
@app.route('/link/<string:id>', methods=['PUT'])
def updateLink(id):
    data = request.get_json()
    links[id] = data
    return jsonify({"message" : "Link updated succesfully on id {}".format(id)})

# Delete operation in CRUD, ie : D -> CRUD
# Endpoint : http://localhost:5000/link/20221222221211518239 (DELETE)
# To delete single link using link's id
@app.route('/link/<string:id>', methods=['DELETE'])
def deleteLink(id):
    del links[id]
    return jsonify({"message" : "Link deleted succesfully on id {}".format(id)})

• We have create our REST API's but we didn't add them to our flask app
• Let's add it to our __init__.py file

./rest_api_basic/__init__.py

# ... some code ...
# Need to add this line after oru flask app instance is created

from project import routes

Reference link

• Flask Documentation
• Flask SQL-Alchemy
• RestX Documentation