main.py

from flask import Flask, jsonify, request


app = Flask(__name__)


user_list = [
    {
        'username': 'abc',
        'password': 'abc'
    },
    {
        'username': '123',
        'password': '123'
    }
]


@app.route('/')
def helloworld():
    return "hello world"


@app.route('/users', methods=['GET'])
def get_users():
    return jsonify(user_list)


@app.route('/user', methods=['POST'])
def create_user():
    user = request.get_json()
    user_check = list(
        filter(
            lambda x: user.get('username') == x['username'], 
            user_list
        )
    )
    if not user_check:
        user_list.append(user)
        return jsonify({
            'message': 'user created'
        })
    else:
        return jsonify(
            {'message': 'user exist'}
        )


@app.route('/user/<username>', methods=['DELETE', 'PUT'])
def delete_user(username):
    user_find = None
    for user in user_list:
        if user['username'] == username:
            user_find = user
    if not user_find:
        return jsonify(
            {'message': 'user not found'}
        )
    if request.method == 'DELETE':
        user_list.remove(user_find)
        return jsonify(
            {'message': 'user deleted'}
        )
    elif request.method == 'PUT':
        # new_passwd = {"password": 'xxxxxxx'}
        new_passwd = request.get_json()
        user_list.remove(user_find)
        user_list.append(
            {
                'username': username,
                'password': new_passwd['password']
            }
        )
        return jsonify(
            {'message': 'user password updated'}
        )



if __name__ == "__main__":
    app.run()