Provide a simple API to convert between foreign exchange rates.

Based on EUR exchange rates provided by European-Central-Bank.

Exchange rates as provided by European Central Bank

• On application startup, the rates are imported from ECB XML feed.
• Uses both daily and 90-day-historic XML feeds.
• Rates are stored in an in-memory database.
• Rates are updated every hour.

NOTE: this project uses Lombok. For full IDE support you might need to install a plugin.

Running the application

mvn spring-boot:run

Use the service

curl -i -H "Accept: application/json" localhost:8080/api/status
curl -i -H "Accept: application/json" localhost:8080/api/currencies
curl -i -H "Accept: application/json" localhost:8080/api/rates/USD/2016-01-21
curl -i -H "Accept: application/json" 'localhost:8080/api/conversion/USD/CHF/1?date=2016-01-21'

Response:

{"isReady":true}

isReady:false until rates have been loaded from webservice for the first time.
isReady:true after rates have been loaded once.

Provides all strings available to use as currency parameter when querying /api/rates/{currency}/{date}

Response:

["AUD","BGN","BRL","CAD","CHF","CNY","CZK","DKK","GBP","HKD","HRK","HUF","IDR","ILS","INR","JPY","KRW","MXN","MYR","NOK","NZD","PHP","PLN","RON","RUB","SEK","SGD","THB","TRY","USD","ZAR"]

Path-Variables:

• {currency} use any string as provided by /api/currencies
• {date} ISO 8601 formatted date

Request & Response:

curl -H "Accept: application/json" localhost:8080/api/rates/USD/2016-01-21
{"rate":1.09}

Where '1.09' is the foreign exchange rate for EUR to USD on 2016-01-21.

Possible http-status codes:

• 200 - requested rate found and returned
• 404 - requested rate not found for currency & date combination (history is until 90 days back, no rates on weekends)
• 503 - if rates have not been loaded yet. corresponds to {"isReady":false} of /api/status

Path-Variables / Request-Variables:

• {fromCurrency} use any string as provided by /api/currencies
• {toCurrency} use any string as provided by /api/currencies
• {amount} amount
• {date} (optional) ISO 8601 formatted date

Request & Response:

curl -H "Accept: application/json" 'localhost:8080/api/conversion/USD/CHF/1?date=2016-01-21'
1.000000000000000000000000000000000046

Possible http-status codes:

• 200 - converted amount returned
• 404 - requested rate not found for currency & date combination (history is until 90 days back, no rates on weekends)
• 503 - if rates have not been loaded yet. corresponds to {"isReady":false} of /api/status

• expose metrics/health/etc. (e.g. via spring boot actuator)
• make scheduling bullet-proof
• improve error handling for data-retrieval (when updating rates)
• add interactive documentation with swagger
• add HATEOAS