Currency Exchange micro-service

This package runs on Lumen PHP framework and is hosted with nginx powered by PHP 7.1.

This package uses the Open Exchange Rates API to get currencies and their exchange rates. It uses Consul key-value store to retrieve the key.

Releases

See Releases page for latest package

Requirements

PHP 7.1+

The following PHP extensions are required:

php-curl
php-json
php-mbstring

Make sure these extensions are installed and enabled.

Configuration

Cache

This service relies heavily on caching.

Make sure to configure it correctly in the .env file.

Sentry

This service will report all exceptions to Sentry if being run in production.

Make sure to configure the SENTRY_DSN string in the .env file.

Consul service discovery

This package is built to be run as a docker container, using Consul for service discovery.

Make sure to configure consul in the .env file.

1. If CONSUL_AWS config key is set to true, and APP_DEBUG is set to false, the system will automatically try and get the AWS instance IP, and defines that as the consul endpoint with port 8500.

2. If the system environment variable CONSUL_IP is set, that will be defined as the consul endpoint with port 8500.

3. Uses the CONSUL_ENDPOINT configuration key from the .env file.

Open Exchange Rates

You will need to store your Open Exchange Rates authentication key in the Consul key-value store, with the key name open_exchange_rates_key.

Notes

When running on local nginx installation, site configuration will need to be updated to include this:

    location / {
        # Modify try_files to include /index.php?$query_string
        try_files $uri $uri/ /index.php?$query_string;
    }

    location ~ \.php$ {
        try_files $uri /index.php =404;
        fastcgi_split_path_info ^(.+\.php)(/.+)$;

        # Only use one of these! Comment out or remove the one that does not apply
        fastcgi_pass unix:/var/run/php7.1-fpm.sock;
        fastcgi_pass 127.0.0.1:9000

        fastcgi_index index.php;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        include fastcgi_params;
    }

Docker with PHP 7.1

This docker uses the juhasz84/ubuntu-nginx-php71-docker:latest image.

See this page to have a look at the github repo.

See this page to have a look at it in hub.docker.com.

Usage

All requests to this service should be prefixed with /v1. For example,

http://currency_exchange:80/v1/list

Authentication

All requests to the API must be authenticated with request headers.

X-API-Key - An authentication token. X-API-Date - A datetime stamp (YYYY-MM-DD HH:MM:SS)

To create an authentication key, create a keyed hash value using the HMAC method (hash_hmac php function with sha256 algorithm), of the API_NAME env key, datetime stamp, and SHARED_SECRET env key.

Example:

$apiName = 'CurrencyExchangeService';
$date = date('Y-m-d H:i:s');
$apiSecret = GetAPISecretHere();
$key = hash_hmac('sha256', $apiName . $date, $apiSecret);

The datetime stamp can not be older than 3 minutes (or whatever the API_SIGNATURE_TIMEOUT value is in your .env file).

List of routes

All currencies should be a 3 digit currency code.

1. GET /list - List available currencies.
2. GET /rates/[currency] - Get the exchange rates for [currency].
   • Can also be provided with a query string to limit results to certain currencies.
   • Query string should be formatted like so: ?symbols[]=EUR&symbols[]=USD.
3. GET /convert/[base]/[convert] - Convert amounts from [base] currency to [convert] currency.
   • Must be provided with a query string containing a list of amounts to convert.
   • Query string should be formatted like so: ?amounts[]=123&amounts[]=456.
4. POST /convert/[base]/[convert] - Convert amounts from [base] currency to [convert] currency.
   • Must be provided with a list of amounts to convert in the POST data.
   • POST data should be formatted like so: amounts[]=123&amounts[]=456.