Work with HTTP headers in Express

Sep 19, 2018

Learn how to read and change HTTP headers in Express using req.headers, req.header() to get one value, res.set() to set a header, and the res.type() shortcut.

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Access HTTP headers values from a request

You can access all the HTTP headers using the Request.headers property:

app.get('/', (req, res) => {
  console.log(req.headers)
})

Use the Request.header() method to access one individual request header’s value:

app.get('/', (req, res) => {
  req.header('User-Agent')
})

Change any HTTP header value for a response

You can change any HTTP header value using Response.set():

res.set('Content-Type', 'text/html')

There is a shortcut for the Content-Type header, however:

res.type('.html')
// => 'text/html'

res.type('html')
// => 'text/html'

res.type('json')
// => 'application/json'

res.type('application/json')
// => 'application/json'

res.type('png')
// => image/png:

Tagged: Express.js · All topics

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