When you run Express apps for production, it is helpful to use a process manager to achieve the following tasks: Restart the app automatically if it crashes. Gain insights into runtime performance and resource consumption. Modify settings dynamically to improve performance. Control clustering. A process manager is somewhat like an application server: it’s a “container” for applications that facilitates deployment, provides high availability, and enables you to manage the application at runtim

Express is a routing and middleware web framework that has minimal functionality of its own: An Express application is essentially a series of middleware function calls. Middleware functions are functions that have access to the request object (req), the response object (res), and the next middleware function in the application’s request-response cycle. The next middleware function is commonly denoted by a variable named next. Middleware functions can perform the following tasks: Execute any co

req.acceptsCharsets(charset [, ...]) Returns the first accepted charset of the specified character sets, based on the request’s Accept-Charset HTTP header field. If none of the specified charsets is accepted, returns false. For more information, or if you have issues or concerns, see accepts.

app.get(name) Returns the value of name app setting, where name is one of strings in the app settings table. For example: app.get('title'); // => undefined app.set('title', 'My Site'); app.get('title'); // => "My Site"

express.static(root, [options]) This is the only built-in middleware function in Express. It serves static files and is based on serve-static. The root argument refers to the root directory from which the static assets are to be served. The file to serve will be determined by combining req.url with the provided root directory. When a file is not found, instead of sending a 404 response, this module will instead call next() to move on to the next middleware, allowing for stacking and fall-backs.

Define error-handling middleware functions in the same way as other middleware functions, except error-handling functions have four arguments instead of three: (err, req, res, next). For example: app.use(function(err, req, res, next) { console.error(err.stack); res.status(500).send('Something broke!'); }); You define error-handling middleware last, after other app.use() and routes calls; for example: var bodyParser = require('body-parser'); var methodOverride = require('method-override');

res.app This property holds a reference to the instance of the Express application that is using the middleware. res.app is identical to the req.app property in the request object.

Overview Middleware functions are functions that have access to the request object (req), the response object (res), and the next middleware function in the application’s request-response cycle. The next middleware function is commonly denoted by a variable named next. Middleware functions can perform the following tasks: Execute any code. Make changes to the request and the response objects. End the request-response cycle. Call the next middleware in the stack. If the current middleware func

req.app This property holds a reference to the instance of the Express application that is using the middleware. If you follow the pattern in which you create a module that just exports a middleware function and require() it in your main file, then the middleware can access the Express instance via req.app For example: //index.js app.get('/viewdirectory', require('./mymiddleware.js')) //mymiddleware.js module.exports = function (req, res) { res.send('The views directory is ' + req.app.get('v

router.route(path) Returns an instance of a single route which you can then use to handle HTTP verbs with optional middleware. Use router.route() to avoid duplicate route naming and thus typo errors. Building on the router.param() example above, the following code shows how to use router.route() to specify various HTTP method handlers. var router = express.Router(); router.param('user_id', function(req, res, next, id) { // sample user, would actually fetch from DB, etc... req.user = {