fabric-samples/asset-transfer-basic/chaincode-javascript/lib/assetTransfer.js

/*
 * Copyright IBM Corp. All Rights Reserved.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

'use strict';

const { Contract } = require('fabric-contract-api');

class AssetTransfer extends Contract {

    async initLedger(ctx) {
        const assets = [
            {
                ID: 'asset1',
                Color: 'blue',
                Size: 5,
                Owner: 'Tomoko',
                AppraisedValue: 300,
            },
            {
                ID: 'asset2',
                Color: 'red',
                Size: 5,
                Owner: 'Brad',
                AppraisedValue: 400,
            },
            {
                ID: 'asset3',
                Color: 'green',
                Size: 10,
                Owner: 'Jin Soo',
                AppraisedValue: 500,
            },
            {
                ID: 'asset4',
                Color: 'yellow',
                Size: 10,
                Owner: 'Max',
                AppraisedValue: 600,
            },
            {
                ID: 'asset5',
                Color: 'black',
                Size: 15,
                Owner: 'Adriana',
                AppraisedValue: 700,
            },
            {
                ID: 'asset6',
                Color: 'white',
                Size: 15,
                Owner: 'Michel',
                AppraisedValue: 800,
            },
        ];

        for (let i = 0; i < assets.length; i++) {
            assets[i].docType = 'asset';
            await ctx.stub.putState(assets[i].ID, Buffer.from(JSON.stringify(assets[i])));
            console.info('Added <--> ', assets[i]);
        }
    }

    // createAsset issues a new asset to the world state with given details.
    async createAsset(ctx, id, color, size, owner, appraisedValue) {
        const asset = {
            ID: id,
            Color: color,
            Size: size,
            Owner: owner,
            AppraisedValue: appraisedValue,
        };

        await ctx.stub.putState(id, Buffer.from(JSON.stringify(asset)));
    }

    // readAsset returns the asset stored in the world state with given id.
    async readAsset(ctx, id) {
        const assetJSON = await ctx.stub.getState(id); // get the asset from chaincode state
        if (!assetJSON || assetJSON.length === 0) {
            throw new Error(`The asset ${id} does not exist`);
        }

        return assetJSON.toString();
    }

    // updateAsset updates an existing asset in the world state with provided parameters.
    async updateAsset(ctx, id, color, size, owner, appraisedValue) {
        const exists = await this.assetExists(ctx, id);
        if (!exists) {
            throw new Error(`The asset ${id} does not exist`);
        }

        // overwritting original asset with new asset
        let updatedAsset = {
            ID: id,
            Color: color,
            Size: size,
            Owner: owner,
            AppraisedValue: appraisedValue,
        };

        return ctx.stub.putState(id, Buffer.from(JSON.stringify(updatedAsset)));
    }

    // deleteAsset deletes an given asset from the world state.
    async deleteAsset(ctx, id) {
        const exists = await this.assetExists(ctx, id);
        if (!exists) {
            throw new Error(`The asset ${id} does not exist`);
        }

        return ctx.stub.deleteState(id);
    }

    // assetExists returns true when asset with given ID exists in world state.
    async assetExists(ctx, id) {
        const assetJSON = await ctx.stub.getState(id);
        if (!assetJSON || assetJSON.length === 0) {
            return false;
        }
        return true;
    }

    // transferAsset updates the owner field of asset with given id in the world state.
    async transferAsset(ctx, id, newOwner) {
        let assetString = await this.readAsset(ctx, id);

        let asset = JSON.parse(assetString);
        asset.Owner = newOwner;

        await ctx.stub.putState(id, Buffer.from(JSON.stringify(asset)));
    }

    // getAllAssets returns all assets found in the world state.
    async getAllAssets(ctx) {
        const allResults = [];
        // range query with empty string for startKey and endKey does an open-ended query of all assets in the chaincode namespace.
        for await (const { key, value } of ctx.stub.getStateByRange("", "")) {
            const strValue = Buffer.from(value).toString('utf8');
            let record;
            try {
                record = JSON.parse(strValue);
            } catch (err) {
                console.log(err);
                record = strValue;
            }
            allResults.push({ Key: key, Record: record });
        }
        console.info(allResults);
        return JSON.stringify(allResults);
    }


}

module.exports = AssetTransfer;