Getting info from the request

To get info from the requesting url (notice that req is the request object in the handler function of routes). Consider this route definition /settings/:user_id and this particular example /settings/32135?field=name

// get the full path
req.originalUrl // => /settings/32135?field=name

// get the user_id param
req.params.user_id // => 32135     

// get the query value of the field
req.query.field // => 'name'

You can also get headers of the request, like this

req.get('Content-Type')
// "text/plain"

To simplify getting other info you can use middlewares. For example, to get the body info of the request, you can use the body-parser middleware, which will transform raw request body into usable format.

var app = require('express')();
var bodyParser = require('body-parser');

app.use(bodyParser.json()); // for parsing application/json
app.use(bodyParser.urlencoded({ extended: true })); // for parsing application/x-www-form-urlencoded

Now suppose a request like this

PUT /settings/32135
{
  "name": "Peter"
}

You can access the posted name like this

req.body.name
// "Peter"

In a similar way, you can access cookies from the request, you also need a middleware like cookie-parser

req.cookies.name