Dependencies:-

Solidity:

npm install -g truffle ethereumjs-testrpc npm install truffle-contract web3 bluebird fetch --save

For more details, refer the package.json file of the project.

If you're cloning this project for reference, issue npm install from the project root to install the dependencies.

Spring Boot:

Create a simple spring boot rest api [/rest/] that will simulate an api response.

Sample Code Snippet:

@RestController public class OracleController {

@GetMapping("/risk/{customerId}")
public String getCustomerRisk(@PathVariable String customerId) {
	System.out.println("Processing for customerId: " + customerId);
	return customerId.equals("C1") ? "OK" : "KO";
}

}

Truffle Config:

You can either use the testrpc to run the development blockchain at 8545 or configure Ganache/ ganache-cli at your preferred port.

Make sure the config is updated to the truffle config and oracle/ client js files

Steps to run the project and test the Oracle implementation:

1. Issue truffle compile and truffle migrate command to compile and deploy the contract
2. In a new terminal, run the oracle.js by issuing node oracle.js
3. In a new terminal, run client.js by issuing node client.js [Repeat this step twice to notice the updates made to the customerRisk value]

*** Note: The simulation uses web3 to communicate with the oracle/ external API and the blockchain

For suggestions/ clarifications, please reach out to [email protected]