Currency Converter

An application for performing currency exchange rate conversions. The app allows users to input the source and target currencies, enter an amount, and trigger the conversion from the source to the target currency. The app displays a list of conversions and current exchange rates for the selected source currency.

Table of Contents

• Business Requirements
• Functional Requirements
• API Endpoints
• Sequence Diagram
• Example API Responses
• Technologies Used
• Partner API
• Configuration
• How to Run
• Future Goals
• License

Business Requirements

1. Currency Conversion: Users should be able to convert between different currencies using up-to-date exchange rates.
2. Currency Symbol Display: The application should provide a list of available currency symbols for users to choose from.
3. Accurate Conversion Rates: Conversion rates must reflect real-time rates from a reliable source.
4. Error Handling: Proper error messages should be displayed to users for invalid requests or server errors.
5. User Privacy: The application should handle user data securely and not store sensitive information unnecessarily.

Functional Requirements

1. GET /symbol Endpoint:

   • Returns a list of 3-character currency codes available for exchange.

2. GET /convert Endpoint:

   • Accepts parameters from, to, and amount.
   • Returns the conversion rate from from currency to to currency based on amount.
   • Provides the converted amount (targetAmount) and the original amount (sourceAmount).

API Endpoints

API Base URL: http://localhost:8080

• GET /symbol: Returns a list of 3-character currency codes available for exchange.
• GET /convert?from=EUR&to=INR&amount=100: Returns the conversion rate.
  • from and to should be the 3-character currency codes available for exchange.
  • amount is the amount on which conversion information will be fetched and displayed.

Sequence Diagram

The following sequence diagram illustrates the interactions between the Client, Server Application, and External API for fetching currency symbols and performing conversions:

Example API Responses

Get Available Currency Symbols

GET /symbol HTTP/1.1
User-Agent: PostmanRuntime/7.30.0
Accept: */*
Cache-Control: no-cache
Postman-Token: 44636757-4908-42d7-90de-f9e6810a3ac3
Host: localhost:8080
Accept-Encoding: gzip, deflate, br
Connection: keep-alive

HTTP/1.1 200 OK
Content-Type: application/json
Transfer-Encoding: chunked
Date: Fri, 30 Dec 2022 04:31:22 GMT
Keep-Alive: timeout=60
Connection: keep-alive

["FJD","MXN","STD","SCR","CDF","BBD","GTQ","CLP","HNL","UGX","ZAR","TND","STN","CUC","BSD","SLL","SDG","IQD","CUP","GMD","TWD","RSD","DOP","KMF","MYR","FKP","XOF","GEL","BTC","UYU","MAD","CVE","TOP","AZN","OMR","PGK","KES","SEK","CNH","BTN","UAH","GNF","ERN","MZN","SVC","ARS","QAR","IRR","XPD","CNY","THB","UZS","XPF","MRU","BDT","LYD","BMD","KWD","PHP","XPT","RUB","PYG","ISK","JMD","COP","MKD","USD","DZD","PAB","GGP","SGD","ETB","JEP","KGS","SOS","VUV","LAK","BND","XAF","LRD","XAG","CHF","HRK","ALL","DJF","VES","ZMW","TZS","VND","XAU","AUD","ILS","GHS","GYD","KPW","BOB","KHR","MDL","IDR","KYD","AMD","BWP","SHP","TRY","LBP","TJS","JOD","AED","HKD","RWF","EUR","LSL","DKK","CAD","BGN","MMK","MUR","NOK","SYP","IMP","ZWL","GIP","RON","LKR","NGN","CRC","CZK","PKR","XCD","ANG","HTG","BHD","KZT","SRD","SZL","SAR","TTD","YER","MVR","AFN","INR","AWG","KRW","NPR","JPY","MNT","AOA","PLN","GBP","SBD","BYN","HUF","BIF","MWK","MGA","XDR","BZD","BAM","EGP","MOP","NAD","SSP","NIO","PEN","NZD","WST","TMT","CLF","BRL"]

Convert Currency

GET /convert?from=EUR&to=INR&amount=100 HTTP/1.1
User-Agent: PostmanRuntime/7.30.0
Accept: */*
Cache-Control: no-cache
Postman-Token: 9c6404df-8d1f-47f0-93ca-ca1b599320a4
Host: localhost:8080
Accept-Encoding: gzip, deflate, br
Connection: keep-alive

HTTP/1.1 200 OK
Content-Type: application/json
Transfer-Encoding: chunked
Date: Fri, 30 Dec 2022 04:32:03 GMT
Keep-Alive: timeout=60
Connection: keep-alive

{"targetCurrency":"INR","sourceCurrency":"EUR","targetAmount":"8824.309774","sourceAmount":"100"}

Technologies Used

• Java 1.8.0_332
• Gradle 4.10.x
• Spring Boot 2.5.2
• JUnit 4.13.2
• exchangerate.host — Partner APIs

Partner API

Exchange rates API is a simple and lightweight free service for current and historical foreign exchange rates & crypto exchange rates.

Configuration

Update partner API configuration in src/main/resources/application.properties:

currency.baseUrl=https://api.exchangerate.host/
currency.path.symbol=latest
currency.path.convert=convert
currency.accessKey=<API_Key>

How to Run

1. Start the Application:

   gradle bootRun

   The server will be available at http://localhost:8080.

2. Run Tests:

   gradle test

Future Goals

• Reorganize conversion API GET /convert
• Add validation for GET /convert
• Improve unit test cases
• Upgrade Gradle, Spring Boot, and JUnit versions

License

This project is licensed under the MIT License. See the LICENSE file for details.

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Developed by Amburi Roy. For any inquiries, please contact via LinkedIn.