This project implements a currency exchange rate API using Symfony 5. The application fetches data from the Open Exchange Rates API, saves these rates into a MySQL database, and leverages Redis for caching to optimize data fetching.

• Command: The console command that fetches exchange rates from the Open Exchange Rates API is located in the src\Command\CurrencyRatesCommand class.
• Controller: The endpoint that returns the exchange rates for a given set of currencies is handled in the src\Controller\ExchangeRatesController class.
• Entity: The src\Entity\CurrencyRate class is an entity class representing a record of a currency exchange rate.
• Tests: The unit tests for the console command and the endpoint are in the tests\CurrencyRatesCommandTest and tests\ExchangeRatesControllerTest classes respectively.

1. Clone this repository

   git clone https://github.com/fvarli/currency_exchange_api.git

2. Install dependencies

   cd repository
   composer install

3. Environment Variables: Create a .env file at the project root and populate the following variables:

   DATABASE_URL=mysql://db_user:[email protected]:3306/db_name
   REDIS_URL=redis://localhost
   OPEN_EXCHANGE_RATES_APP_ID=your_open_exchange_rates_app_id
   REDIS_HOST=localhost
   REDIS_PORT=6379
   

   Update db_user, db_password, db_name and your_open_exchange_rates_app_id with your actual database credentials and Open Exchange Rates App ID.

4. Database: Run the Doctrine migrations to create the database schema:

   php bin/console doctrine:migrations:migrate

1. Fetching Exchange Rates: Run the console command to fetch the exchange rates and save them into the MySQL database and Redis:

   php bin/console app:currency:rates USD EUR,JPY,GBP,TRY

   Replace USD, EUR, JPY, GBP , TRY with the currencies you want to fetch.

2. Getting Exchange Rates: Send a GET request to the endpoint to get the exchange rates for a given set of currencies:

   GET /api/exchange-rates?base_currency=USD&target_currencies=EUR,GBP,JPY,TRY
   

   Replace USD in base_currency and EUR,GBP,JPY,TRY in target_currencies with the currencies you want.

To schedule the command to run automatically, you can add an entry to your system's crontab. The following command will run the fetch command every day at 1 AM server time:

0 1 * * * cd /path/to/project/root && php bin/console app:currency:rates USD EUR,GBP,JPY,TRY >> /var/log/currency_rates_command.log 2>&1

Replace /path/to/project/root with the actual path to your project's root directory. This command also logs the output of the command to /var/log/currency_rates_command.log for monitoring purposes.

Remember to replace EUR,GBP,JPY,TRY with the actual currencies you want to fetch.

To run the tests, use the following command:

php bin/phpunit

The test classes CurrencyRatesCommandTest and ExchangeRatesControllerTest are available for testing the functionality of the console command and the endpoint respectively.