Currency Converter

A Python3 currency converter using exchange rates from ExchangeRate-API with hourly rate updates and Redis server for cache.

You can run the converter as a CLI application or a web API application. The converter allows conversion from/to these currencies and is able to decode currency symbols¹ based on the following definitions.

Prerequisites

This application requires a running Redis server, you can configure the connection to a Redis server in data_storage.py module. See Redis documentation on how to set up a Redis server or use this article if you are on a Windows machine.

The converter also uses the following python packages:

flask==0.12.2
click==6.7
redis==2.10.6

You can use requirements.txt to set up your environment.

How to use the converter

The application uses 3 input parameters - [amount], [input_currency] and optional [output_currency]. It provides conversion of [amount] in [input_currency] to [output_currency] or all available currencies if [output_currency] was not specified. The [input_currency] and [output_currency] can be specified either by a 3 letter currency code following ISO 4217 or by a currency symbol¹.

CLI application

Simply run currency_converter.py module with listed parameters.

Example uses:

a)

./currency_converter.py --amount 100.0 --input_currency EUR --output_currency CZK

Result:

{
    "input": {
        "amount": 100.0,
        "currency": "EUR"
    },
    "output": {
        "CZK": 2541.21
    }
}

b)

./currency_converter.py --amount 10.92 --input_currency £ 

Result:

{
    "input": {
        "amount": 10.92,
        "currency": "GBP"
    },
    "output": {
        "EUR": 12.25,
        "AED": 55.53,
        "AMD": 7257.99,
        ...
    }
}

Web API application

To start the server for the web API, run the following commands:

$ export FLASK_APP=currency_converter.py
$ flask run

Use set instead of export to run the server on Windows machines. Head over to the Flask documentation if you need more information about Flask.

Example uses:

a)

GET /currency_converter?amount=0.9&input_currency=¥&output_currency=AUD HTTP/1.1

Result:

{
  "input": {
    "amount": 0.9, 
    "currency": "CNY"
  }, 
  "output": {
    "AUD": 0.18
  }
}

b)

GET /currency_converter?amount=10.92&input_currency=£ HTTP/1.1

Result:

{
  "input": {
    "amount": 10.92, 
    "currency": "GBP"
  }, 
  "output": {
    "AED": 55.53, 
    "AMD": 7257.99, 
    "ANG": 26.94, 
    ...
  }
}

Using converter module alone

You can also use the Converter object from the converter module as it is. It can decode currency symbols for you or you can call the conversion method without the CLI/API in your project. Note that this will still require a running Redis server for data storage.

from converter import Converter

c = Converter()
print(c.decode_symbol("$"))
print(c.convert_currency(amount=100, input_currency="CZK", output_currency="£"))

Result:

USD
{'input': {'amount': 100, 'currency': 'CZK'}, 'output': {'GBP': 3.51}}

---

¹ Symbol mapping

symbol	currency code		symbol	currency code		symbol	currency code
$	USD		Rp	IDR		₱	PHP
€	EUR		₪	ILS		₨	PKR
£	GBP		₹	INR		zł	PLN
د.إ.	AED		د.ع.	IQD		₲	PYG
դր.	AMD		﷼	IRR		ر.ق.	QAR
Kz	AOA		د.أ.	JOD		RON	RON
KM	BAM		￥	JPY		дин.	RSD
৳	BDT		Ksh	KES		руб.	RUB
лв.	BGN		៛	KHR		ر.س.	SAR
د.ب.	BHD		₩	KRW		kr	SEK
R$	BRL		د.ك.	KWD		฿	THB
P	BWP		₸	KZT		د.ت.	TND
CHF	CHF		ل.ل.	LBP		TL	TRY
¥	CNY		රු.	LKR		NT$	TWD
Kč	CZK		د.م.	MAD		TSh	TZS
Kr.	DKK		MKD	MKD		₴	UAH
ج.م.	EGP		K	MMK		UZS	UZS
ብር	ETB		MUR	MUR		Bs.F.	VEF
GHS	GHS		RM	MYR		₫	VND
Q	GTQ		₦	NGN		FCFA	XAF
L	HNL		ر.ع.	OMR		CFA	XOF
kn	HRK		B$	PAB		R	ZAR
Ft	HUF		S/	PEN