upgrade any http(s) server with error handling via domains

npm install doh
16 downloads in the last day
127 downloads in the last week
554 downloads in the last month


upgrade any http(s) server with error handling via domains



  • guarantees a request will receive a response when errors occur
  • handles any error during a request callback (no need for fn(err, res))
  • sends 500 with error message by default
  • default and custom error pages


npm install doh


upgrade(server, options)

Add error handling to an existing server.

var upgrade = require('doh').upgrade
  , server = require('http').createServer();

server.on('request', function () {
  process.nextTick(function() {
    thisFunctionClearlyDoesNotExist(); // errors, ends the response, returns an error page


// call upgrade when you want
// to start handling errors


Create an adhoc error handler that will capture errors in a domain and respond to with the correct error.

var options = {template: 'my-err-template.html'}
  , server = require('http').createServer()
  , doh = require('doh');

server.on('request', function(req, res) { 
  var handler = doh.createHandler(options); {
    process.nextTick(function() {
      throw 'anything'; // will be sent to the response


Return an error page based on an Error object.

var options = {template: 'my-err-template.html'}
  , server = require('http').createServer()
  , doh = require('doh')
  , respond = doh.createResponder({template: 'my-err-template.html'}) // template - optional

server.on('request', function(req, res) { 
  var err = new Error('my custom error');
  respond(err, req, res); // sends an error page

error page

Error Screen

crash only

By default doh handles errors on a domain and responds with an error page. Since node is crash only by design, you'll usually want to process.exit() when an error occurs.

upgrade(server).on('request:error', function(err, req, res) {
  // at this point the response has been sent
  // but we can still log out everything before we
  // restart the server

  console.error(err, req, res);


You can pass an options object to doh.upgrade(server, options) to override default behavior.

  • template - path to an ejs error template. Passed req, res, and err. See assets/error.html.


npm test

note - Since doh is entirely concerned with error handling, it requires a custom test runner that does not rely on throw for failures (see test.js for more).



npm loves you