NBP Data Middleware

This project is an Express.js + React app that fetches data from the National Polish Bank (NBP), creates its own API for some of the endpoints, and serves the data as middleware.

Tools used to build

• Node.js
• Express.js
• React.js
• SASS
• Jest
• Docker

Requirements

• Docker

Installation and starting the server

1. Clone this repository using git clone
2. Navigate to the project directory.

Starting the Server

To start the server run Docker and the following command:

docker-compose up

This will start the server on http://localhost:3000 for the front-end (React endpoint test UI) and http://localhost:8888 for the back-end API.

Running tests

To run the test, navigate to the ./backend directory and run the following command:

npm test

API Endpoints

The following endpoints are available:

Average

• Endpoint: /api/averages/:currency/:date
• Method: GET
• Description: Retrieves the average exchange rate for a specific currency on a specific date from the NBP API.
• Query Parameters:
  • currency: The three-letter code of the currency (e.g. GBP, USD, EUR, note: currency code is not case-sensitive).
  • date: The date in the YYYY-MM-DD format.
• Example Request: http://localhost:8888/api/averages/GBP/2023-01-02
• Example Response:

{
  "code": "GBP",
  "date": "2023-01-02",
  "average": 5.2768
}

Maximum and minimum average value for the past N quotations

- Endpoint: `/api/max-min-differences/:currency/:quotation` - Method: `GET` - Description: Retrieves the maximum and minimum average exchange rate for a specific currency for the specific number of the last quotations from the NBP API. - Query Parameters: - `currency`: The three-letter code of the currency (e.g. `GBP`, `USD`, `EUR`, note: currency code is not case-sensitive). - `quotation`: The number of the last quotations (note: number has to be in range of <1;255>). - Example Request: `http://localhost:8888/api/max-min-averages/EUR/185` - Example Response (`max` and `min` in response can vary):

{
  "code": "EUR",
  "quotations": "185",
  "max": 4.8711,
  "min": 4.5887
}

Major difference of exchange bid and ask rates for the past N quotations

- Endpoint: `/api/major-differences/:currency/:quotation` - Method: `GET` - Description: Retrieves the one-day major difference in exchange bid and ask rates for a specific currency for the specific number of the last quotations from the NBP API. - Query Parameters: - `currency`: The three-letter code of the currency (e.g. `GBP`, `USD`, `EUR`, note: currency code is not case-sensitive). - `quotation`: The number of the last quotations (note: number has to be in range of <1;255>). - Example Request: `http://localhost:8888/api/major-differences/JPY/140` - Example Response (`majorDifference` in response can vary):

{
  "code": "JPY",
  "quotations": "140",
  "majorDifference": 0.00069
}

React.js UI

Run the app and navigate in browser to http://localhost:3000 to explore the endpoint tester UI

Screenshots of the UI

• Defaultly initialized app
  
  
• Average endpoint http://localhost:8888/api/averages/JPY/2022-10-28 response
  
  
• Maximum and mininum endpoint http://localhost:8888/api/max-min-averages/JPY/255 response
  
  
• Major difference endpoint http://localhost:8888/api/major-differences/GBP/150 response
  
  
• Invalid request error