fabric-contract-api

The fabric-contract-api provides the contract interface. a high level API for application developers to implement Smart Contracts. Within Hyperledger Fabric, Smart Contracts are also known as Chaincode. Working with this API provides a high level entry point to writing business logic. (this contract interface is new in version 1.3)

Detailed explanation on the concept and programming model can be found here: http://hyperledger-fabric.readthedocs.io/en/latest/chaincode.html.

Contract Interface

Installation

npm install --save fabric-contract-api

Usage

Implement a class that ends the contract class, a contsturctor is needed. The other functions will be invokable functions of your Smart Contract

// updatevalues.js
'use strict';

// SDK Library to asset with writing the logic
const { Contract } = require('fabric-contract-api');

// Business logic (well just util but still it's general purpose logic)
const util = require('util');

/**
 * Support the Updating of values within the SmartContract
 */
class UpdateValuesContract extends Contract

    constructor(){
		super('org.mynamespace.updates');
	}

	async transactionA(ctx, newValue) {
		// retrieve existing chaincode states
		let oldValue = await ctx.stub.getState(key);

		await ctx.stub.putState(key, Buffer.from(newValue));

		return Buffer.from(newValue.toString());
	}

	async transactionB(ctx) {
	  //  .....
	}

};

module.exports = UpdateValuesContract

As with standard node modules make sure that this class is exported as follows.

// index.js
'use strict';

const UpdateValues = require('./updatevalues')
module.exports.contracts = ['UpdateValues'];

Note: In order to make this contract runnable in version 1.3, also install the fabric-shim module as below, and ensure that the 'start' script in package.json refers to startChaincode

  "scripts": {
	"start": "fabric-chaincode-node start"
  }

API Reference

Visit fabric-shim.github.io 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.