Build restful ap is with python and flask
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This document provides instructions for building a RESTful API with Flask that allows users to be created, viewed, updated, and deleted. It discusses installing Python, Flask, Flask-SQLAlchemy, and Flask-Marshmallow. It then demonstrates how to create a user model and schema, and build API endpoints to add a new user, retrieve all users, get a single user by ID, update a user, and delete a user. Finally, it provides instructions for running the application and testing the API with Postman.
![CreateInstance & Set Sqlite Path and flask object
app = Flask(__name__)
basedir = os.path.abspath(os.path.dirname(__file__))
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + os.path.join(basedir,
'api.sqlite')
db = SQLAlchemy(app)
ma = Marshmallow(app)
Create a app instance and set sqlite path in app config,after it binding SQLAlchemy
and Marshmallow into our flask application.](https://image.slidesharecdn.com/buildrestfulapiswithpythonandflask-190416064255/85/Build-restful-ap-is-with-python-and-flask-12-320.jpg)
![Create a New User Api
# endpoint to create new user
//code
@app.route("/user", methods=["POST"])
def add_user():
username = request.json['username']
email = request.json['email']
new_user = User(username, email)
db.session.add(new_user)
db.session.commit()
return user_schema.jsonify(new_user)
//code
On this part we define endpoint to create new user. First we set the route to “/user” and set HTTP methods to POST. After set the route
and methods we define function that will executed if we access this endpoint. On this function first we get username and email from
request data. After that we create new user using data from request data. Last we add new user to data base and show new user in JSON
form as response.](https://image.slidesharecdn.com/buildrestfulapiswithpythonandflask-190416064255/85/Build-restful-ap-is-with-python-and-flask-15-320.jpg)
![Show All users Api
# endpoint to show all users
//code
@app.route("/user", methods=["GET"])
def get_user():
all_users = User.query.all()
result = users_schema.dump(all_users)
return jsonify(result.data)
//code
//On this part we define endpoint to get list of all users and show the result as
JSON response.](https://image.slidesharecdn.com/buildrestfulapiswithpythonandflask-190416064255/85/Build-restful-ap-is-with-python-and-flask-16-320.jpg)
![View user Api
# endpoint to get user detail by id
//code
@app.route("/user/<id>", methods=["GET"])
def user_detail(id):
user = User.query.get(id)
return user_schema.jsonify(user)
//code
//on this part we define endpoint to get user data, but instead of get all the
user here we just get data from one user based on id. If you look carefully at the
route, you can see different pattern on the route of this endpoint. Patern like
“<id>” is parameter, so you can change it with everything you want. This
parameter should put on function parameter(in this case def user_detail(id)) so
we can get this parameter value inside function.](https://image.slidesharecdn.com/buildrestfulapiswithpythonandflask-190416064255/85/Build-restful-ap-is-with-python-and-flask-17-320.jpg)
![Update User Api
# endpoint to update user
//code
@app.route("/user/<id>", methods=["PUT"])
def user_update(id):
user = User.query.get(id)
username = request.json['username']
email = request.json['email']
user.email = email
user.username = username
db.session.commit()
return user_schema.jsonify(user)
//code
we define endpoint to update user. First we call user that related with given id on parameter. Then we update username and email value
of this user with value from request data using put method.](https://image.slidesharecdn.com/buildrestfulapiswithpythonandflask-190416064255/85/Build-restful-ap-is-with-python-and-flask-18-320.jpg)
![Delete user Api
# endpoint to delete user
//code
@app.route("/user/<id>", methods=["DELETE"])
def user_delete(id):
user = User.query.get(id)
db.session.delete(user)
db.session.commit()
return user_schema.jsonify(user)
//code
#endpoint to delete user. First we call user that related with given id on
parameter. Then we delete it.](https://image.slidesharecdn.com/buildrestfulapiswithpythonandflask-190416064255/85/Build-restful-ap-is-with-python-and-flask-19-320.jpg)
Build restful ap is with python and flask
- 1. Build Restful APIs with Python and Flask Presented by : Jeetendra Singh
- 2. About this Presetation • This guide will walk you through building a Restful APi with Flask . At the end, you'll build a simple Crud APIs. The API will have endpoints that can be used to add user, view users, update user, delete user & view user.
- 3. At the end , following endpints will be available: • GET - /user => Retrieve all users • POST - /user - Add a new user • GET - /user/<id> - get single user by id • PUT - /user/<id> - Update a user • DELETE - /user/<id> - Delete a user
- 4. Install Python Debian or Ubuntu > sudo apt install python3 Fedora > sudo dnf install python3 Opensuse > sudo zypper install python3 Windows: Download latest python from python.org and install it Verify Version > python3 --version it will show version like : Python 3.6.1
- 5. Install virtualenv virtualenv is a virtual Python environment builder. It helps a user to create multiple Python environments side-by-side. Thereby, it can avoid compatibility issues between the different versions of the libraries. The following command installs virtualenv pip install virtualenv or Sudo apt-get install virtualenv
- 6. Create and Run Virtual Env • Once installed, new virtual environment is created in a folder. >mkdir newproj >cd newproj >virtualenv venv • To activate corresponding environment, on Linux/OS X, use the following − > venv/bin/activate • On Windows, following can be used > venvscriptsactivate
- 7. Install Flask > pip install Flask # pip is a package manager in python, it will available bydefault once you install python
- 8. “Hello World” In Flask • create a file index.py with following code: > python index.py now run on http://localhost:5000 (5000 is default port you may change it)
- 9. Installing flask-sqlalchemy and flask-marshmallow • SQLAlchemy is python SQL toolkit and ORM that gives developer the full power and flexibility of SQL. Where flask-sqlalchemy is flask extension that adds support for SQLAlchemy to flask application(http://flask-sqlalchemy.pocoo.org/2.1/). • In other hand flask-marshmallow is flask extension to integrate flask with marshmallow(an object serialization/deserialization library). In this presentation we use flask-marshmallow to rendered json response Turn next to install above
- 10. Installation • $ pip install flask_sqlalchemy • $ pip install flask_marshmallow • $ pip install marshmallow-sqlalchemy
- 11. Create a Api.py with following code //code from flask import Flask, request, jsonify from flask_sqlalchemy import SQLAlchemy from flask_marshmallow import Marshmallow import os //code Description : On this part we import all module that needed by our application. We import Flask to create instance of web application, request to get request data, jsonify to turns the JSON output into a Response object with the application/json mimetype, SQAlchemy from flask_sqlalchemy to accessing database, and Marshmallow from flask_marshmallow to serialized object.
- 12. CreateInstance & Set Sqlite Path and flask object app = Flask(__name__) basedir = os.path.abspath(os.path.dirname(__file__)) app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + os.path.join(basedir, 'api.sqlite') db = SQLAlchemy(app) ma = Marshmallow(app) Create a app instance and set sqlite path in app config,after it binding SQLAlchemy and Marshmallow into our flask application.
- 13. Declare Model Class and constructor //code class User(db.Model): id = db.Column(db.Integer, primary_key=True) username = db.Column(db.String(80), unique=True) email = db.Column(db.String(120), unique=True) def __init__(self, username, email): self.username = username self.email = email //code
- 14. Create a Response Schema //code class UserSchema(ma.Schema): class Meta: # Fields to expose fields = ('id','username', 'email') user_schema = UserSchema() users_schema = UserSchema(many=True) //code //This part defined structure of response of our endpoint. We want that all of our endpoint will have JSON response. Here we define that our JSON response will have 3 keys(id, username, and email). Also we defined user_schema as instance of UserSchema, and user_schemas as instances of list of UserSchema.
- 15. Create a New User Api # endpoint to create new user //code @app.route("/user", methods=["POST"]) def add_user(): username = request.json['username'] email = request.json['email'] new_user = User(username, email) db.session.add(new_user) db.session.commit() return user_schema.jsonify(new_user) //code On this part we define endpoint to create new user. First we set the route to “/user” and set HTTP methods to POST. After set the route and methods we define function that will executed if we access this endpoint. On this function first we get username and email from request data. After that we create new user using data from request data. Last we add new user to data base and show new user in JSON form as response.
- 16. Show All users Api # endpoint to show all users //code @app.route("/user", methods=["GET"]) def get_user(): all_users = User.query.all() result = users_schema.dump(all_users) return jsonify(result.data) //code //On this part we define endpoint to get list of all users and show the result as JSON response.
- 17. View user Api # endpoint to get user detail by id //code @app.route("/user/<id>", methods=["GET"]) def user_detail(id): user = User.query.get(id) return user_schema.jsonify(user) //code //on this part we define endpoint to get user data, but instead of get all the user here we just get data from one user based on id. If you look carefully at the route, you can see different pattern on the route of this endpoint. Patern like “<id>” is parameter, so you can change it with everything you want. This parameter should put on function parameter(in this case def user_detail(id)) so we can get this parameter value inside function.
- 18. Update User Api # endpoint to update user //code @app.route("/user/<id>", methods=["PUT"]) def user_update(id): user = User.query.get(id) username = request.json['username'] email = request.json['email'] user.email = email user.username = username db.session.commit() return user_schema.jsonify(user) //code we define endpoint to update user. First we call user that related with given id on parameter. Then we update username and email value of this user with value from request data using put method.
- 19. Delete user Api # endpoint to delete user //code @app.route("/user/<id>", methods=["DELETE"]) def user_delete(id): user = User.query.get(id) db.session.delete(user) db.session.commit() return user_schema.jsonify(user) //code #endpoint to delete user. First we call user that related with given id on parameter. Then we delete it.
- 20. Before Running Actions Now • enter into python interactive shell using following command in your terminal: > python • import db object and generate SQLite database Use following code in python interactive shell > from api import db > db.create_all() Api.sqlite will be generated inside your project folder
- 21. Run Application > python crud.py Now apis are in action , try via postman Screenshot Attached in Next Slide
- 23. Thanks • Thanks to Bear With Me