node.js - Express.js Response Timeout

Question

PROBLEM

I've been looking for request/response timeouts for Express.js but everything seems to be related to the connection rather than the request/response itself.

If a request is taking a long time, it should be timed out. Obviously this shouldn't happen but even a simple mistake as having a route handler without a call to the callback or without res.send(), the browser will keep waiting for a reply forever.

An empty route handler is a perfect example of this.

app.get('/sessions/', function(req, res, callback){});

FIX

I added the following before app.use(app,router); and it seemed to add the timeout functionality. Does anyone have any experience/opinion on this?

app.use(function(req, res, next){
    res.setTimeout(120000, function(){
        console.log('Request has timed out.');
            res.send(408);
        });

    next();
});

Note that I've set the timeout to 2 minutes.

Answer 1

There is already a Connect Middleware for Timeout support:

var timeout = express.timeout // express v3 and below
var timeout = require('connect-timeout'); //express v4

app.use(timeout(120000));
app.use(haltOnTimedout);

function haltOnTimedout(req, res, next){
  if (!req.timedout) next();
}

If you plan on using the Timeout middleware as a top-level middleware like above, the haltOnTimedOut middleware needs to be the last middleware defined in the stack and is used for catching the timeout event. Thanks @Aichholzer for the update.

Side Note:

Keep in mind that if you roll your own timeout middleware, 4xx status codes are for client errors and 5xx are for server errors. 408s are reserved for when:

The client did not produce a request within the time that the server was prepared to wait. The client MAY repeat the request without modifications at any later time.