iav0207/moneytransfer

Coding task: REST API implementation

MoneyApp

This is a solution to coding task, not a real app.

Description

Implementation of RESTful API for money transfers between accounts.

• Simplicity and optimization for speed of development were at the highest priority here.
• No authentication mechanism provided. Assuming it's an internal API.

Technical info

• The project is written in Dropwizard framework, which uses embedded Jetty server, Jersey HTTP client, Jackson for serialization.
• No ORM framework was used. Data access implemented via JDBI / SQL Object interface.
• No DI framework.
• No Swagger doc, though it'd be nice.
• DBMS: in-memory H2 DB.
• Testing: TestNG + Mockito.

Short API description

Supported methods:

GET     /accounts           - get account info by id
POST    /accounts/open      - open a new account in specified currency
POST    /accounts/close     - close account by id
GET     /currencies/list    - get list of supported currencies (numeric and ISO codes)
GET     /money/balance      - get account balance
POST    /money/deposit      - deposit funds into account
POST    /money/transfer     - transfer money to another account
POST    /money/withdraw     - withdraw funds from account

For money representation in the API 'micro-money' is used, e.g. 1.50 USD is represented by number 1_500_000 for USD account.

Project structure

• api – API objects (JSON models), such as requests, responses and domain model objects; and error codes as well.
• core – money model and core transactional operations.
• db – data access layer.
• health – smoke startup health check.
• resources – REST endpoints.

Run it!

1. Run mvn clean install to build the application
2. Start application with java -jar target/money-transfer-1.0-SNAPSHOT.jar server config.yml
3. Run demo:
   • To see API workflow demo run python3 src/demo/api_workflow_demo.py, or see script source and its output example. It also illustrates request/response structures.
   • To see some possible error responses demo run python3 src/demo/api_errors_demo.py, or see source and its output example.