hpcore/examples/echo_contract/contract.js

process.on('uncaughtException', (err) => {
    console.error('There was an uncaught error', err)
})
const fs = require('fs')

//console.log("===Sample contract started===");
let hpargs = JSON.parse(fs.readFileSync(0, 'utf8'));
//console.log(hpargs);

// We just save execution args as an example state file change.
if (!hpargs.readonly)
    fs.appendFileSync("exects.txt", "ts:" + hpargs.ts + "\n");

Object.keys(hpargs.usrfd).forEach(function (key, index) {
    let userfds = hpargs.usrfd[key];

    if (userfds[0] != -1) {
        let userinput = fs.readFileSync(userfds[0], 'utf8');

        // Append user input to a state file if not in read only mode.
        if (!hpargs.readonly)
            fs.appendFileSync("userinputs.txt", userinput + "\n");
        
        if (userinput == "ts")
            fs.writeSync(userfds[1], fs.readFileSync("exects.txt"));
        else
            fs.writeSync(userfds[1], "Echoing: " + userinput);
    }
});

if (!hpargs.readonly) {

    if (hpargs.nplfd[0] != -1) {
        let nplinput = fs.readFileSync(hpargs.nplfd[0], 'utf8');
        console.log("Input received from peers:");
        console.log(nplinput);
        fs.writeSync(hpargs.nplfd[1], "Echoing: " + nplinput);
    }

    if (hpargs.hpfd[0] != -1) {
        let hpinput = fs.readFileSync(hpargs.hpfd[0], 'utf8');
        console.log("Input received from hp:");
        console.log(hpinput);
        fs.writeSync(hpargs.hpfd[1], "Echoing: " + hpinput);
    }
}

//console.log("===Sample contract ended===");