app.py

from flask import Flask,render_template,request
import requests

api_key = "Sizin API Keyiniz"

url = "http://data.fixer.io/api/latest?access_key=" + api_key

app = Flask(__name__)
@app.route("/",methods = ["GET","POST"])
def index():
    if request.method == "POST":
        firstCurrency = request.form.get("firstCurrency") # USD
        secondCurrency = request.form.get("secondCurrency") # TRY

        amount = request.form.get("amount") # 15
        response = requests.get(url)
        app.logger.info(response)

        infos =  response.json()

        firstValue = infos["rates"][firstCurrency] # 1.231066
        secondValue = infos["rates"][secondCurrency] # 8.690815

        result = (secondValue / firstValue) * float(amount)

        currencyInfo = dict()

        currencyInfo["firstCurrency"] = firstCurrency
        currencyInfo["secondCurrency"] = secondCurrency
        currencyInfo["amount"] = amount
        currencyInfo["result"] = result

        return render_template("index.html",info = currencyInfo)
    else:
        return render_template("index.html" )
if __name__ == "__main__":
    app.run(debug=True)