Rewrite a sample implementation of API Server on Hyperledger Fabric v2.2

apiserver.js

const express = require('express');
const bodyParser = require('body-parser');

const app = express();
app.use(bodyParser.json());

// Setting for Hyperledger Fabric
const { Wallets, Gateway } = require('fabric-network');
const fs = require('fs');
const path = require('path');
const ccpPath = path.resolve(__dirname, '.',  'connection-org1.json');


app.get('/api/queryallcars', async function (req, res) {
    try {

        let ccp = JSON.parse(fs.readFileSync(ccpPath, 'utf8'));
        // Create a new file system based wallet for managing identities.
        const walletPath = path.join(process.cwd(), 'wallet');
        const wallet = await Wallets.newFileSystemWallet(walletPath);
        console.log(`Wallet path: ${walletPath}`);

        // Check to see if we've already enrolled the user.
        const identity = await wallet.get('appUser');
        if (!identity) {
            console.log('An identity for the user "appUser" does not exist in the wallet');
            console.log('Run the registerUser.js application before retrying');
            return;
        }

        // Create a new gateway for connecting to our peer node.
        const gateway = new Gateway();
        await gateway.connect(ccp, { wallet, identity: 'appUser', discovery: { enabled: true, asLocalhost: false } });

        // Get the network (channel) our contract is deployed to.
        const network = await gateway.getNetwork('mychannel');

        // Get the contract from the network.
        const contract = network.getContract('fabcar');

        // Evaluate the specified transaction.
        // queryCar transaction - requires 1 argument, ex: ('queryCar', 'CAR4')
        // queryAllCars transaction - requires no arguments, ex: ('queryAllCars')
        const result = await contract.evaluateTransaction('queryAllCars');
        console.log(`Transaction has been evaluated, result is: ${result.toString()}`);
        res.status(200).json({response: result.toString()});

        // Disconnect from the gateway.
        await gateway.disconnect();

    } catch (error) {
        console.error(`Failed to evaluate transaction: ${error}`);
        res.status(500).json({error: error});
        process.exit(1);
    }
});


app.get('/api/query/:car_index', async function (req, res) {
    try {

        let ccp = JSON.parse(fs.readFileSync(ccpPath, 'utf8'));
        // Create a new file system based wallet for managing identities.
        const walletPath = path.join(process.cwd(), 'wallet');
        const wallet = await Wallets.newFileSystemWallet(walletPath);
        console.log(`Wallet path: ${walletPath}`);

        // Check to see if we've already enrolled the user.
        const identity = await wallet.get('appUser');
        if (!identity) {
            console.log('An identity for the user "appUser" does not exist in the wallet');
            console.log('Run the registerUser.js application before retrying');
            return;
        }

        // Create a new gateway for connecting to our peer node.
        const gateway = new Gateway();
        await gateway.connect(ccp, { wallet, identity: 'appUser', discovery: { enabled: true, asLocalhost: false } });

        // Get the network (channel) our contract is deployed to.
        const network = await gateway.getNetwork('mychannel');

        // Get the contract from the network.
        const contract = network.getContract('fabcar');

        // Evaluate the specified transaction.
        // queryCar transaction - requires 1 argument, ex: ('queryCar', 'CAR4')
        // queryAllCars transaction - requires no arguments, ex: ('queryAllCars')
        const result = await contract.evaluateTransaction('queryCar', req.params.car_index);
        console.log(`Transaction has been evaluated, result is: ${result.toString()}`);
        res.status(200).json({response: result.toString()});

        // Disconnect from the gateway.
        await gateway.disconnect();

    } catch (error) {
        console.error(`Failed to evaluate transaction: ${error}`);
        res.status(500).json({error: error});
        process.exit(1);
    }
});

app.post('/api/addcar/', async function (req, res) {
    try {

        let ccp = JSON.parse(fs.readFileSync(ccpPath, 'utf8'));
        // Create a new file system based wallet for managing identities.
        const walletPath = path.join(process.cwd(), 'wallet');
        const wallet = await Wallets.newFileSystemWallet(walletPath);
        console.log(`Wallet path: ${walletPath}`);

        // Check to see if we've already enrolled the user.
        const identity = await wallet.get('appUser');
        if (!identity) {
            console.log('An identity for the user "appUser" does not exist in the wallet');
            console.log('Run the registerUser.js application before retrying');
            return;
        }

        // Create a new gateway for connecting to our peer node.
        const gateway = new Gateway();
        await gateway.connect(ccp, { wallet, identity: 'appUser', discovery: { enabled: true, asLocalhost: false } });

        // Get the network (channel) our contract is deployed to.
        const network = await gateway.getNetwork('mychannel');

        // Get the contract from the network.
        const contract = network.getContract('fabcar');

        // Submit the specified transaction.
        // createCar transaction - requires 5 argument, ex: ('createCar', 'CAR12', 'Honda', 'Accord', 'Black', 'Tom')
        // changeCarOwner transaction - requires 2 args , ex: ('changeCarOwner', 'CAR10', 'Dave')
        await contract.submitTransaction('createCar', req.body.carid, req.body.make, req.body.model, req.body.colour, req.body.owner);
        console.log('Transaction has been submitted');
        res.send('Transaction has been submitted');

        // Disconnect from the gateway.
        await gateway.disconnect();

    } catch (error) {
        console.error(`Failed to submit transaction: ${error}`);
        process.exit(1);
    }
})

app.put('/api/changeowner/:car_index', async function (req, res) {
    try {

        let ccp = JSON.parse(fs.readFileSync(ccpPath, 'utf8'));
        // Create a new file system based wallet for managing identities.
        const walletPath = path.join(process.cwd(), 'wallet');
        const wallet = await Wallets.newFileSystemWallet(walletPath);
        console.log(`Wallet path: ${walletPath}`);

        // Check to see if we've already enrolled the user.
        const identity = await wallet.get('appUser');
        if (!identity) {
            console.log('An identity for the user "appUser" does not exist in the wallet');
            console.log('Run the registerUser.js application before retrying');
            return;
        }

        // Create a new gateway for connecting to our peer node.
        const gateway = new Gateway();
        await gateway.connect(ccp, { wallet, identity: 'appUser', discovery: { enabled: true, asLocalhost: false } });

        // Get the network (channel) our contract is deployed to.
        const network = await gateway.getNetwork('mychannel');

        // Get the contract from the network.
        const contract = network.getContract('fabcar');

        // Submit the specified transaction.
        // createCar transaction - requires 5 argument, ex: ('createCar', 'CAR12', 'Honda', 'Accord', 'Black', 'Tom')
        // changeCarOwner transaction - requires 2 args , ex: ('changeCarOwner', 'CAR10', 'Dave')
        await contract.submitTransaction('changeCarOwner', req.params.car_index, req.body.owner);
        console.log('Transaction has been submitted');
        res.send('Transaction has been submitted');

        // Disconnect from the gateway.
        await gateway.disconnect();

    } catch (error) {
        console.error(`Failed to submit transaction: ${error}`);
        process.exit(1);
    }
})

app.listen(8080);