This CorDapp implements an oracle service that allows nodes to:
- Request the Nth prime number
- Request the oracle's signature to prove that the number included in their transaction is actually the Nth prime number
Whilst the functionality is superfluous (as primes can be verified deterministically via the contract code), this CorDapp is a simple example of how to structure an oracle service that provides querying and signing abilities. In the real world, oracles would instead provide and sign statements about stock prices, exchange rates, and other data.
This repo is split into three CorDapps:
- A base CorDapp, which includes the state and contract definition, as well as some utility flows that need to be shared by both the Oracle service and the client
- A client CorDapp, which implements a flow to create numbers involving oracle-validated prime numbers
- A service, which implements the primes oracle
For development environment setup, please refer to: Setup Guide.
Open a terminal and go to the project root directory and type: (to deploy the nodes using bootstrapper)
./gradlew clean build deployNodes
Then type: (to run the nodes)
./build/nodes/runnodes
Go to the interactive node shell for PartyA, and request the 5th prime from the oracle using the CreatePrime flow:
flow start CreatePrime index: 5
We can then see the state wrapping the 5th prime (11) in our vault by running:
run vaultQuery contractStateType: net.corda.samples.oracle.states.PrimeState