Huge News!Announcing our $40M Series B led by Abstract Ventures.Learn More
Socket
Sign inDemoInstall
Socket

express-domain-middleware

Package Overview
Dependencies
Maintainers
1
Versions
2
Alerts
File Explorer

Advanced tools

Socket logo

Install Socket

Detect and block malicious and high-risk dependencies

Install

express-domain-middleware

wrap express request/response with node domains

  • 0.1.0
  • latest
  • Source
  • npm
  • Socket score

Version published
Maintainers
1
Created
Source

express-domain-middleware

Build Status

Hi! Are you using process.uncaughtException in your express apps to keep them running?

OR...Do you just let your process crash on any unhandled exception and restart it?

Do you find it hard to pass "request.id" to 8 nested database calls so you can keep a context of what request you're working on?

How do you associate log entries with a specific request? Passing the request around everywhere again?

Domains can help.

USE DOMAINS

First, read this

Second, realize once you enable domains process.domain will give you the active domain.

Third, use this middleware to bind each request/response pair to its own domain.

express.use(require('express-domain-middleware'));

express-domain-middleware api

var domainMiddleware = require('express-domain-middleware');
domainMiddleware = function(req, res, next)

Exports a function matching the signature of express middleware. Binds incoming request & response from express to a new domain. Assigns the domain a unique id by calling domainMiddleware.id(req).

If the domain emits an error event, domainMiddleware will call next(err) with the error event from the domain. This allows existing express specific error handling middleware to function as if the error was hanlded by your application code. Allow me to demonstrate with an example:

///old-school
app.get('/error', function(req, res, next) {
  db.query('SELECT happiness()', function(err, rows) {
    if(err) return next(err);    
    fs.readFile('alskdjflasd', function(err, contents) {
      if(err) return next(err);
      process.nextTick(function() {
        throw new Error("congratulations, your node process crashed and the user request disconnected in a jarring way");
      });
    });
  })
});

now with less crashing...

//with domain-middleware
app.use(require('express-domain-middleware'));
app.use(app.router);
app.use(function errorHandler(err, req, res, next) {
  console.log('error on request %d %s %s: %j', process.domain.id, req.method, req.url, err);
  res.send(500, "Something bad happened. :(");
  if(err.domain) {
    //you should think about gracefully stopping & respawning your server
    //since an unhandled error might put your application into an unknown state
  }
});
app.get('/error', function(req, res, next) {
  db.query('SELECT happiness()', process.domain.intercept(function(rows) {
    fs.readFile('asldkfjasdf', process.domain.intercept(function(contents) {
      process.nextTick(process.domain.intercept(function() {
        throw new Error("The individual request will be passed to the express error handler, and your application will keep running.");
      }));
    }));
  }));
});

I have to recommend using okay to gracefully fallback in the absence of domains. Plus..it's terse. Go, code golf!

var ok = require('okay');
app.use(require('express-domain-middleware'));
app.use(app.router);
app.use(function errorHandler(err, req, res, next) {
  console.log('error on request %d %s %s: %j', process.domain.id, req.method, req.url, err);
  res.send(500, "Something bad happened. :(");
});
app.get('/error', function(req, res, next) {
  db.query('SELECT happiness()', ok(next, function(rows) {
    fs.readFile('asldkfjasdf', ok(next, function(contents) {
      process.nextTick(ok(next, function() {
        throw new Error("The individual request will be passed to the express error handler, and your application will keep running.");
      }));
    }));
  }));
});

license

MIT

Keywords

FAQs

Package last updated on 20 May 2013

Did you know?

Socket

Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.

Install

Related posts

SocketSocket SOC 2 Logo

Product

  • Package Alerts
  • Integrations
  • Docs
  • Pricing
  • FAQ
  • Roadmap
  • Changelog

Packages

npm

Stay in touch

Get open source security insights delivered straight into your inbox.


  • Terms
  • Privacy
  • Security

Made with ⚡️ by Socket Inc