app.py

#!/usr/bin/python3
from flask import Flask
from flask_restful import Resource, Api, reqparse
import pandas as pd
import ast


app = Flask(__name__)
api = Api(app)


class Users(Resource):
    #methods go here
    def get(self):
        data = pd.read_csv('users.csv') #read csv
        data = data.to_dict() #conert dataframe to dictionary
        return {'data':data}, 200

    def post(self):
        parser = reqparse.RequestParser()

        parser.add_argument('userId', required=True)
        parser.add_argument('name', required=True)
        parser.add_argument('city', required=True)

        args = parser.parse_args()

        # read our CSV
        data = pd.read_csv('users.csv')

        if args['userId'] in list(data['userId']):
            return {
                'message': f"'{args['userId']}' already exists."
            }, 401
        else:
            # create new dataframe containing new values
            new_data = pd.DataFrame({
                'userId': args['userId'],
                'name': args['name'],
                'city': args['city'],
                'locations': [[]]
            })


        # add the newly provided values
        data = data.append(new_data, ignore_index=True)
        # save back to csv
        data.to_csv('users.csv', index=False) #saves the data
        return {'data': data.to_dict()}, 200

    def put(self):
        parser = reqparse.RequestParser() #initialize
        parser.add_argument('userId', required=True) # add args
        parser.add_argument('location', required=True)
        args = parser.parse_args() #parse arguments to dictionary

        #read our csv
        data = pd.read_csv('users.csv')

        if args['userId'] in list(data['userId']):
            # evaluate strings of lists to lists
            data['locations'] = data['locations'].apply(
                lambda x: ast.literal_eval(x)
            )
            # select our user
            user_data = data[data['userId'] == args['userId']]

            # update user's locations
            user_data['locations'] = user_data['locations'].values[0]\
                .append(args['location'])

            # save back to csv
            data.to_csv('users.csv', index=False)
            #return data and 200 OK
            return {'data': data.to_dict()}, 200

        else:
            # otherwise the userId does not exist
            return {
                'message': f"'{args['userId']}' user not found."
            }, 404


    def delete(self):
        parser = reqparse.RequestParser()  # initialize
        parser.add_argument('userId', required=True)  # add userId arg
        args = parser.parse_args()  # parse arguments to dictionary

        # read our CSV
        data = pd.read_csv('users.csv')

        if args['userId'] in list(data['userId']):
            # remove data entry matching given userId
            data = data[data['userId'] != args['userId']]

            # save back to CSV
            data.to_csv('users.csv', index=False)
            # return data and 200 OK
            return {'data': data.to_dict()}, 200
        else:
            # otherwise we return 404 because userId does not exist
            return {
                'message': f"'{args['userId']}' user not found."
            }, 404


class Locations(Resource):
    #methods go here
    def get(self):
        data = pd.read_csv('locations.csv')
        data = data.to_dict()
        return {'data':data}, 200


api.add_resource(Users, '/users') # '/users' is our entry point for Users
api.add_resource(Locations, '/locations') # and '/locations' iis our entry point

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=7000, debug=True)