CODEWITHSUNDEEP
node.jsexpress
Joe
Joe

Reputation: 4234

Set a header in middleware node.js express framework

I have a middleware doing some auth. In this auth-method I need to set a response header.

server.get('/api/users, auth(), getUsers);

My authmethod:

module.exports = (isProduction) => {
  return function(req, res, next){
     ...

     next();

  }
}

How do I attach a header in this auth function?

Upvotes: 9

Views: 18647

Answers (3)

CoolOppo
CoolOppo

Reputation: 533

How you actually use it as middleware.

app.use(function (req, res, next) {
    res.setHeader('access-control-allow-origin', '*');
    next()
})

Upvotes: 4

adamrights
adamrights

Reputation: 1731

This is not a node.js core question but rather a question on express.js.

In that case your reference is: http://expressjs.com/en/4x/api.html#res.set

The set() function's signature is: res.set(field [, value])

The res object is a wrapper around node's native http.response api.

You can call .set() multiple times in express.js middleware as long as they occur before the next() function is invoked, which calls the following middleware in the chain.

There is nothing special about next(). But if the following middleware writes the headers, by calling res.send() or even res.redirect(), then one can no longer set the headers.

You can call set multiple times, and you can use an object to pass multiple headers, as in the documentation example:

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

res.set({
  'Content-Type': 'text/plain',
  'Content-Length': '123',
  'ETag': '12345'
});

Upvotes: 2

ThomasThiebaud
ThomasThiebaud

Reputation: 11969

I assume you are using express.js. In express, there is a set function (documentation here. You can use it like this

res.set('<header name>', '<header value>')

before calling next()

Upvotes: 13

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