The fabric-shim provides the chaincode interface, a lower level API for implementing "Smart Contracts". To confirm that this is the same as the fabric-shim in previous versions of Hyperledger Fabric.
Detailed explanation on the concept and programming model can be found here: https://hyperledger-fabric.readthedocs.io/en/latest/smartcontract/smartcontract.html.
Chaincode Interface
Installation
npm install --save fabric-shimUsage
The chaincode interface contains two methods to be implemented:
const shim = require('fabric-shim');
const Chaincode = class {
async Init(stub) {
// use the instantiate input arguments to decide initial chaincode state values
// save the initial states
await stub.putState(key, Buffer.from(aStringValue));
return shim.success(Buffer.from('Initialized Successfully!'));
}
async Invoke(stub) {
// use the invoke input arguments to decide intended changes
// retrieve existing chaincode states
let oldValue = await stub.getState(key);
// calculate new state values and saves them
let newValue = oldValue + delta;
await stub.putState(key, Buffer.from(newValue));
return shim.success(Buffer.from(newValue.toString()));
}
};Start the chaincode process and listen for incoming endorsement requests:
shim.start(new Chaincode());API Reference
Visit API Reference and click on "Classes" link in the navigation bar on the top to view the list of class APIs.
Support
Tested with node.js 8.9.0 (LTS).
License
This package is distributed under the Apache License, Version 2.0, see LICENSE.txt for more information.