h-kurniawan / forex-proxy

Local Proxy for Forex rates

ForexProxy

A web service that acts as a proxy to the real foreign exchange service, one-frame.

Running the service

Using docker

docker-compose up

Using Maven wrapper

From the project root run the following command

./mvnw spring-boot:run

In a new terminal window/tab, run one-frame using docker

docker run -p 8085:8080 paidyinc/one-frame

Usage

GET /rates

Get the latest currency rates.

Resource URL

http://localhost:8080/rates?pair={currency_pair_0}&pair={currency_pair_1}&...pair={currency_pair_n}

Parameters

• pair - Required query parameter that is the concatenation of two different currency codes, e.g. USDJPY. One or more pairs per request are allowed.

Example request

Using a browser or any REST client.

http://localhost:8080/rates?pair=USDJPY

Example response

[
  {
    "from": "USD",
    "to": "JPY",
    "bid": 0.5098366425706436,
    "ask": 0.13104034760723204,
    "price": 0.32043849508893785,
    "time_stamp": "2022-09-10T06:31:01.002Z"
  }
]

Limitations

one-frame can only accept 1000 requests per day. To alleviate this issue, ForexProxy will cache each requested currency pair. When a 429 (Too Many Requests) is returned by one-frame or any error for that matter, ForexProxy will try to get that currency pair from the cache.

This however is not foolproof. If a currency pair is requested and one-frame returns an error and the pair does not exist in cache, then an error will be returned to the user.

To make ForexProxy more resilient, there needs to be a background worker that would build all the combinations of all currency pairs and store them in cache.
However due to time, this is not implemented.

Tests

To run the tests, from the project root run the following command

./mvnw test