app_flask.py

from flask import Flask, render_template, request, jsonify

app = Flask(__name__)


@app.route('/', methods=['GET', 'POST']) # To render Homepage
def home_page():
    return "Home Page"


@app.route('/via_postman', methods=['POST']) # for calling the API
def calculator():
    if (request.method=='POST'):
        operation=request.json['operation']
        num1=int(request.json['num1'])
        num2 = int(request.json['num2'])
        if(operation=='add'):
            r=num1+num2
            result= 'the sum of '+str(num1)+' and '+str(num2) +' is '+str(r)
        if (operation == 'subtract'):
            r = num1 - num2
            result = 'the difference of ' + str(num1) + ' and ' + str(num2) + ' is ' + str(r)
        if (operation == 'multiply'):
            r = num1 * num2
            result = 'the product of ' + str(num1) + ' and ' + str(num2) + ' is ' + str(r)
        if (operation == 'divide'):
            r = num1 / num2
            result = 'the quotient when ' + str(num1) + ' is divided by ' + str(num2) + ' is ' + str(r)
        return jsonify(result)


if __name__ == '__main__':
    app.run(debug=True)