Restifyapi: Can't set headers after they are sent

Question

Hi Im building two side app on Restifyapi for my friends but when its started i typed first message and its works message sended second terminal but when i typed seccond message server terminal gives error

This is server :

var restify = require('restify');
var apiai = require('apiai');
var app = apiai("4a8fad8f64874e11bc5d1aa5ea8f96f9");
var chalk = require('chalk')
var sleep = require('sleep')
var clients = require('restify-clients');
const readline = require('readline');
const tls = require('tls');
    const server = restify.createServer({
    name: 'FridayAI',
    version: '1.8.0',
});

const rl = readline.createInterface({
   input: process.stdin,
   output: process.stdout,
});

console.log(chalk.yellow('\nSuccesfull\n'));
console.log(chalk.yellow('Starting on 5 seconds\n'));

server.use(restify.plugins.fullResponse());
server.use(restify.plugins.acceptParser(server.acceptable));
server.use(restify.plugins.queryParser());
server.use(restify.plugins.bodyParser());
server.pre(restify.plugins.pre.context());

function welcome(req, res, next) {
   res.send('Welcome')
   next()
}

server.get('/s', welcome);

function respond(req, res, next) {
   rl.on('line', (input) => {
      res.noCache()
      res.send(`${input}`);
      res.end() 
   })
}

server.patch('/', respond);

server.listen(8080, function () {
   console.log('%s listening at %s', server.name, server.url , 'Version:' , server.version);
});

And This is client

var assert = require('assert');
var clients = require('restify-clients');
const readline = require('readline');
var chalk = require('chalk')
var restify = require('restify');
var sleep = require('sleep')
const notifier = require('node-notifier');
const path = require('path')
const tls = require('tls');

var client = clients.createJsonClient({
  url: 'http://localhost:8080',
  version: '1.8.0',
});

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
});

client.get('/s', function (err, req, res, obj) {
  assert.ifError(err);
  console.log(chalk.magenta(obj));
})

client.patch('/', function (err, req, res, obj) {
  assert.ifError(err);
  console.log(chalk.magenta('FridayAI:', obj));
})

Error:

Error: Can't set headers after they are sent.
at validateHeader (_http_outgoing.js:494:11)
at ServerResponse.setHeader (_http_outgoing.js:501:3)
at ServerResponse.noCache (C:\Users\ahmet\Desktop\FridayAI\FridayAPI\node_modules\restify\lib\response.js:91:14)
at Interface.rl.on (C:\Users\ahmet\Desktop\FridayAI\FridayAPI\api.js:51:9)
at emitOne (events.js:116:13)
at Interface.emit (events.js:211:7)
at Interface._onLine (readline.js:282:10)
at Interface._line (readline.js:631:8)
at Interface._ttyWrite (readline.js:911:14)
at ReadStream.onkeypress (readline.js:160:10)

How can I send unliminited message on terminal thanks for help

Answer 1

try changing the function to this

function respond(req, res, next) {
res.noCache()
rl.on('line', (input) => {
res.send(`${input}`);
    res.end() 

})
}

also, not sure of which Restify version you use, but you should "return next()" at the end to send the response;