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Currency Conversion Application

This is a Symfony(7.1) application for fetching, storing, and converting currency exchange rates. It pulls exchange rates from two sources: the European Central Bank (ECB) and the Central Bank of Russia (CBR). The application can convert currencies directly or indirectly via available base currencies (EUR or RUB) and provides a REST API endpoint for currency conversion.

Features

• Fetch daily exchange rates from the ECB and CBR.
• Store exchange rates in a database using Doctrine ORM.
• Support for conversion between any two currencies, including indirect conversions via EUR or RUB as base currencies.
• REST API endpoint to handle currency conversion requests.
• Unit and integration tests for command and service functionality.

Prerequisites

• PHP 8.1 or higher
• Composer
• Symfony CLI
• MySQL or another supported database

Installation

1. Clone the Repository

   git clone <repository-url>
   cd <repository-directory>

2. Install Dependencies

   composer install

3. Configure Environment Variables

   Copy .env.example to .env and update the necessary variables:

   cp .env.example .env

   Update the following environment variables:

   DATABASE_URL=mysql://db_user:db_password@127.0.0.1:3306/currency_conversion_db
   ECB_URL=https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml
   CBR_URL=https://www.cbr.ru/scripts/XML_daily.asp

4. Set Up the Database

   php bin/console doctrine:database:create
   php bin/console doctrine:migrations:migrate

5. Run the Application

   You can use the Symfony CLI to run the development server:

   symfony serve

   The application will be available at http://127.0.0.1:8000.

Usage

1. Fetching Exchange Rates

The application provides a Symfony console command to fetch and store daily exchange rates from the ECB or CBR:

php bin/console app:fetch-exchange-rates [ECB|CBR]

• Replace [ECB|CBR] with either ECB or CBR to specify the data source (defaults to ECB if omitted).

2. Converting Currencies

The application provides an API endpoint for currency conversion. You can use curl or any REST client to interact with it.

• Endpoint: /api/convert

• Method: POST

• Request Body:

  {
    "from": "USD",
    "to": "CZK",
    "amount": 100
  }

• Example Request:

  curl --location 'http://127.0.0.1:8000/api/convert' \
  --header 'Content-Type: application/json' \
  --data '{
      "from": "USD",
      "to": "CZK",
      "amount": 100
  }'

• Response:

  {
    "from": "USD",
    "to": "CZK",
    "original_amount": 100,
    "converted_amount": 2500.00
  }

3. Testing

The application includes unit and integration tests to ensure functionality.

• Run All Tests:

  php bin/phpunit

• Run Specific Tests:

  php bin/phpunit tests/Service/CurrencyConverterTest.php
  php bin/phpunit tests/Command/FetchExchangeRatesCommandTest.php

Project Structure

• src/Command/FetchExchangeRatesCommand.php: Console command to fetch exchange rates from ECB or CBR.
• src/Service/CurrencyConverter.php: Service to handle currency conversion, supporting both direct and indirect conversions.
• src/Controller/Api/CurrencyController.php: REST API controller for handling currency conversion requests.
• tests/: Contains unit and integration tests.

License

This project is open-source and available under the MIT License.

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