fabric-shim

v2.5.7

A node.js implementation of Hyperledger Fabric chaincode shim, to allow endorsing peers and user-provided chaincodes to communicate with each other

fabric-shim Hyperledger Fabric Fabric Shim

Readme Versions Dependencies Scripts

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-shim

Usage

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()));
    }
};