Todo Flask API

Objective 1 (day1) :

- GET /: Retrieve a message that will return object

- GET /users: Retrieve all of the users

• You can always use any Postam/Fiddler/HTTP library to test the API if you prefer that.

---

Creating the API

• Create a directory todo
• Run cd todo/
• Inside the todo, run pipenv shell to create your own environment and enter into it.
• Install dependencies. We need just two: Flask and Flask-SQLAlchemy(for database mapper). Run the below commands

~/ pipenv install flask

~/ pipenv install flask-sqlalchemy

Creating the first route '/'

• create a file called app.py and add the following

    from flask import Flask, jsonify
    from flask_sqlalchemy import SQLAlchemy
  
    app = Flask(__name__)
  
    @app.route('/)
    def home():
        return {
            'message': 'Welcome to building API'
        }, 200
  
    if__name__ = '__main__':
        app.run()
  

• On terminal run server with flask run and send your request to the link generated.

• When we sent a request to the endpoint / via postman or browser, you'll see response of object

{
    'message': 'Welcome to building API'
}

which means everything is working fine

---

Its time to build our user model

• but the complete app will have user and to-do models.
• These two models will have a one-to-many relationship — i.e., one user can have many to-dos, and one to-do needs to have a user
• Check App.py for complete codes, We connected db(sqlite) and SQLALchemy wrapper

Testing user model in flask shell

• Open a Flask shell ,use,(flask shell), and let’s test our models.

>>> from app import User, db
>>> db.create_all()
>>> instance_user = User(
    name='George',
    email='gokumu@67.com'
)
>>> User.query.all()

• After running db.create_all(), these models have been created, and we can query them.
• The db.Model object exposes our models to a query method that we use to query them.

Inserting some rows into db

>>> db.session.add(instance_user)
>>> db.session.commit()

• The function db.session.add adds a variable to the database temporarily. The second function, db.session.commit, saves it permanently. Other functions include db.session.add_all, which takes an array of objects to be added to the database, and db.session.delete, which deletes an object

• Test your users endpoint now, and good you'll have the /users endpoint returning a list of users in json format

Objective 2, Day 2:

- POST /add-user: Creating new users

- PUT /update-user/id: updating users details

- GET /users/id: Get single user

- DELETE /delete-user/id: Delete an existing user

Posting new user route and method

---

Method 1

    @app.route('/add-user', methods=["POST"])
    def create_user():
        user = request.get_json()

        new_user = User(
            name = user['name'],
            email = user['email']
        )

        db.session.add(new_user)
        db.session.commit()

        return jsonify({
            "id": new_user.id,
            "name": new_user.name,
            "email": new_user.email
        }), 201

In the above method we have a decorator for defining the route, and a method create user

• In the method create-user(), we have

    user = request.get_json()
  

  • this line gets the users details that are being added from the front-end and storing it in user object. But the details here must be in json object format.

  • It then assigns the details when creating a new instance of user in this line,

      new_user = User(
              name = user['name'],
              email = user['email']
          )
    

  • Then we add the user to db and save it using the following line:

      db.session.add(new_user)
      db.session.commit()
    

  • Finally we return a serialized user object that was added, with the help of jsonify from flask.

---

Method 2

@app.route('/add-user', methods=["POST"])
def create_user():
    new_user = User(
        name = request.form.get("name"),
        email = request.form.get("email")
    )

    db.session.add(new_user)
    db.session.commit()

    resp = {
        "message": "user created succesfully",
        "user": {
        'id': new_user.id,
        'name': new_user.name,
        'email': new_user.email
        }
    }

    return make_response(
        jsonify(resp), 201
    )

• In the above method we use the form method from flask requests, request.form.get('something from the client form')

• This grabs the details from client form and assigns them to the instance varibales.

   new_user = User(
           name = request.form.get("name"),
           email = request.form.get("email")
       )
  

  • NOTE: In this method we get the data from the form itself, the type of data to use from the client client should be of form-data type.

---

Updating User and Deleting user

• To update/delete user we must target the unique user we want to update/delete.

• then we must query the user from the db, by filtering the target user by the target id,

    user_from_db = User.query.filter_by(id=id).first_or_404()
  

• for delete

    user_to_delete = User.query.filter_by(id=id).first()
  

And wahala, you can test your endpoints via postman or fiddler.

        Thanks, 😊😊😊😊

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