hp-devkit/docker/code-templates/nodejs/starter/src/contract.js

const HotPocket = require('hotpocket-nodejs-contract');
const { _projname_ } = require('./_projname_');

// Hot Pocket smart contract is defined as a function which takes the Hot Pocket ExecutionContext as an argument.
// This function gets invoked every consensus round and whenever a user sends a out-of-concensus read-request.
async function contract(ctx) {

    // Create our application logic component.
    // This pattern allows us to test the application logic independently of Hot Pocket.
    const app = new _projname_();

    // Wire-up output emissions from the application before we pass user inputs to it.
    app.sendOutput = async (userPubKey, output) => {
        // In Hot Pocket, each user is represented by their Ed25519 public key.
        const user = ctx.users.find(userPubKey);
        await user.send(output)
    }
    
    // In 'readonly' mode, nothing our contract does will get persisted on the ledger. The benefit is
    // readonly messages gets processed much faster due to not being subjected to consensus.
    // We should only use readonly mode for returning/replying data for the requesting user.
    //
    // In consensus mode (NOT read-only), we can do anything like persisting to data storage and/or
    // sending data to any connected user at the time. Everything will get subjected to consensus so
    // there is a time-penalty.
    const isReadOnly = ctx.readonly;

    // Process user inputs.
    // Loop through list of users who have sent us inputs.
    for (const user of ctx.users.list()) {

        // Loop through inputs sent by each user.
        for (const input of user.inputs) {

            // Read the data buffer sent by user (this can be any kind of data like string, json or binary data).
            const buf = await ctx.users.read(input);

            // Let's assume all data buffers for this contract are JSON.
            // In real-world apps, we need to gracefully fitler out invalid data formats for our contract.
            const message = JSON.parse(buf);

            // Pass the JSON message to our application logic component.
            await app.handleRequest(userPubKey, message, isReadOnly);
        }
    }
}

const hpc = new HotPocket.Contract();
hpc.init(contract);