This project was inspired by the experience gained during Qala Developer Program (2021), which has by itself done magnitudes in exposing me to approaches to Bitcoin and Lightning software design.
This section describes the JayCoin application’s architecture. JayCoin is a simple implementation of a Blockchain. It's capable of mining a block, validating the blockchain, and returning the list of blocks (blockchain).
This feature gets the state of the blockchain at any given time by returning the list of mined blocks. If no block is mined yet, it returns the Genesis Block which is a default block created by the system. Blocks are added to the blockchain after a successful mine
Also known as proof of work, it performs hash (SHA-256) operation on parameters on a block, then compares the
result against the set target. If the comparison returns true then we have the proof of work (nonce), the block
is added to the chain and a successful message is returned.
This is used to check if the blockchain has been altered or attacked. It checks the hash of blocks and height of the blockchain to validate if the blockchain is valid or not.
Note: this is a simple application to help understand the concept of block creation,
mining (proof of work), block hashing, and block validating.
- Java 11 or Higher
- Docker
- User can get all the blocks in the blockchain
- When a user mines a coin, a block created on top of the previous block
- The blockchain should have an initial Genesis block
- User can validate if the blockchain is valid.
Jaycoin exposes REST APIs for seamless interaction, it uses Java (Spring boot) at the backend as the language of implementation. This helps create a modern, robust, easy to maintain, and reliable system.
This architecture facilitates fast and parallel development, making existing business objects reusable. Test data injection via setter methods was made easy because of the architecture creation of JavaBeans classes.
This application comprises controller and service. Every layer has a well-defined role. It’s extremely important service layer defines an interface that helps other layers interface with it, as this will make the service much easier to maintain. For example, the controller layer can only interact with the service layer. This helps achieve separation of concerns.
Exposes APIs to clients. This layer receives the query requests and passes them to the Business Logic layer (Service).
Also known as the Service layer receives the query requests from the controller, validates them, performs business logic, and returns the response to the controller layer.
The application is written using Java, and Docker for containerization. To start the application, open the root folder of the project on a terminal, then run the command below:
% ./mvnw clean install
% docker-compose -f ./infrastructure/docker/docker-compose01.yml up -d
Use docker ps on the same terminal to confirm the applications are up. Use a REST client (cURL or POSTMAN) to access the APIs.
| Requirement | API | Status Code |
|---|---|---|
| Get Blockchain | http://127.0.0.1:9090/api/v1/getChain | 200 |
| Validate Chain | http://127.0.0.1:9090/api/v1/validateChain | 200 |
| Mine Block | http://127.0.0.1:9090/api/v1/mineBlock | 200 |