req.subdomains An array of subdomains in the domain name of the request. // Host: "tobi.ferrets.example.com" req.subdomains // => ["ferrets", "tobi"]

app.post(path, callback [, callback ...]) Routes HTTP POST requests to the specified path with the specified callback functions. For more information, see the routing guide. You can provide multiple callback functions that behave just like middleware, except that these callbacks can invoke next('route') to bypass the remaining route callback(s). You can use this mechanism to impose pre-conditions on a route, then pass control to subsequent routes if there’s no reason to proceed with the current

app.enabled(name) Returns true if the setting name is enabled (true), where name is one of the properties from the app settings table. app.enabled('trust proxy'); // => false app.enable('trust proxy'); app.enabled('trust proxy'); // => true

req.ips When the trust proxy setting does not evaluate to false, this property contains an array of IP addresses specified in the X-Forwarded-For request header. Otherwise, it contains an empty array. This header can be set by the client or by the proxy. For example, if X-Forwarded-For is client, proxy1, proxy2, req.ips would be ["client", "proxy1", "proxy2"], where proxy2 is the furthest downstream.

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.params This property is an object containing properties mapped to the named route “parameters”. For example, if you have the route /user/:name, then the “name” property is available as req.params.name. This object defaults to {}. // GET /user/tj req.params.name // => "tj" When you use a regular expression for the route definition, capture groups are provided in the array using req.params[n], where n is the nth capture group. This rule is applied to unnamed wild card matches with string

app.disable(name) Sets the Boolean setting name to false, where name is one of the properties from the app settings table. Calling app.set('foo', false) for a Boolean property is the same as calling app.disable('foo'). For example: app.disable('trust proxy'); app.get('trust proxy'); // => false

res.sendFile(path [, options] [, fn]) res.sendFile() is supported by Express v4.8.0 onwards Transfers the file at the given path. Sets the Content-Type response HTTP header field based on the filename’s extension. Unless the root option is set in the options object, path must be an absolute path to the file. The following table provides details on the options parameter. Property Description Default Availability maxAge Sets the max-age property of the Cache-Control header in milliseconds or a

req.param(name [, defaultValue]) Deprecated. Use either req.params, req.body or req.query, as applicable. Returns the value of param name when present. // ?name=tobi req.param('name') // => "tobi" // POST name=tobi req.param('name') // => "tobi" // /user/tobi for /user/:name req.param('name') // => "tobi" Lookup is performed in the following order: req.params req.body req.query Optionally, you can specify defaultValue to set a default value if the parameter is not found in any o

req.secure A Boolean property that is true if a TLS connection is established. Equivalent to: 'https' == req.protocol;