exchange

Service is dead, see Formicka/exchangerate.host#245

Go library for current & historical exchange rates, forex & cryptocurrency conversion, fluctuation, and timeseries using the new Free foreign exchange rates API by arzzen (GitHub)

Features:

Currency conversion, historical & current exchange rates, timeseries and fluctuations.
No authentication/token needed!
Select any base currency.
171 forex currency and 6000+ cryptocurrency!
No dependencies, only standard library.
Easy to use.

Upgrading from asvvvad/exchange to version 1.0.0 (for further upgrading please view CHANGELOG.md):

no built-in caching, do it yourself
changed return types from big.Float to float64 and the second argument's type for ConvertTo() from int to float64

Usage:

go get -u github.com/rehhouari/exchange

package main

import (
	"fmt"

	"github.com/rehhouari/exchange"
)

func main() {
	// Create a new Exchange instance and set USD as the base currency for the exchange rates and conversion
	ex := exchange.New("USD")
	// convert 10 USD to EUR
	fmt.Println(ex.ConvertTo("EUR", 10.0))

	// You can convert between 171 fiat and +6000 cryptocurrency as well!
	// convert 10 USD to BTC
	fmt.Println(ex.ConvertTo("BTC", 10.0))
	// convert 10 USD to EUR at 2012-12-12 (date must be in the format YYYY-MM-DD)
	fmt.Println(ex.ConvertAt("2012-12-12", "EUR", 10.0))

	// Get the available forex/fiat codes ([]string)
	forexCodes, _ := ex.ForexCodes()

	// Get the available crypto codes ([]string)
	// Warning: +6000
	cryptoCodes, _ := ex.CryptoCodes()
	fmt.Println(cryptoCodes)

	// Get the forex codes data, includes code and description.
	forexData, _ := ex.ForexData()

	// Get the crypto codes data, includes code and description.
	// Warning: +6000
	cryptoData, _ := ex.CryptoData()
	fmt.Println(cryptoData["BTC"]["code"])

	// loop through the forex codes
	for _, code := range forexCodes {
		// print the forex codes data in the format: USD: US Dollar
		fmt.Println(code+":", forexData[code]["description"])
	}

	// Change the base currency to euro
	ex.SetBase("EUR")
	// Get the latest exchange rates with all currencies (Base is EUR)
	// exchangerate.host update them at midnight GMT so make sure to cache it till next day
	fmt.Println(ex.LatestRatesAll())

	// Get the latest rates with multiple currencies, not all (USD and JPY only)
	fmt.Println(ex.LatestRatesMultiple([]string{"USD", "JPY"}))

	// Get the exchange rates at 2012-12-12 but only with USD
	fmt.Println(ex.HistoricalRatesSingle("2012-12-12", "USD"))

	// Get historical rates between 2012 12 10 and 2012 12 12 for JPY and GBP
	fmt.Println(ex.TimeseriesMultiple("2012-12-10", "2012-12-12", []string{"USD", "JPY"}))

	// Get the fluctuation between 2012 12 10 and 2012 12 12 with USD
	fluctuation, _ := ex.FluctuationSingle("2012-12-10", "2012-12-12", "USD")
	// Print the change
	fmt.Println(fluctuation["change"])
}

Results returned by each method:

ConvertTo, ConvertAt, HistoricalRatesSingle, LatestRatesSingle
- float64, error
LatestRatesAll, LatestRatesMultiple, HistoricalRatesAll, HistoricalRatesMultiple:
- map[symbol(string)]rate(float64)
ForexCodes
- []string{codes}, error
ForexData
- map[symbol]map[ code description ]string, error
CryptoCodes
- []string{codes}, error
CryptoData
- map[symbol]map[ symbol name ]string, error
FluctuationAll, FluctuationMultiple,
- map[symbol]map[ start_rate end_rate change change_pct ]float64, error
FluctuationSingle
- map[ start_rate end_rate change change_pct ]float64, error
TimeseriesAll, TimeseriesMultiple
- map[date]map[symbols]float64, error
TimeseriesSingle
- map[date]map[symbol]float64, error

Notes:

Exchange rates are refreshed every midnight GMT, cache results when using!
You can use All, Multiple, Single with all of LatestRates, HistoricalRates, Timeseries and Fluctuation.
Oldest date for historical rates and conversion is 1999-01-04
Maximum allowed timeframe for Timeseries is 365 days
Use decimal to handle float64 results with decimal.NewFromFloat.

Input validation with the appropriate errors for all methods is provided to help debug

Any help and contribution is welcome!

This is my first Go library and I had trouble with JSON parsing (and I still do, didn't use bitly/simplejson to reduce dependencies). There's a lot of room for improvement.

rehhouari / exchange