Vary with dynamic config

[laat]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the regression has not already been reported

Last working version

8.x.x

Stopped working in version

9.x.x

Node.js version

any

Operating system

Linux

Operating system version (i.e. 20.04, 11.3, 10)

any

💥 Regression Report

this testcase has two different origins (example.com and sample.com):

fastify-cors/test/cors.test.js

Lines 126 to 221 in 3cf8f61

	test('Should support dynamic config (callback)', t => {
	t.plan(18)
	const configs = [{
	origin: 'example.com',
	methods: 'GET',
	credentials: true,
	exposedHeaders: ['foo', 'bar'],
	allowedHeaders: ['baz', 'woo'],
	maxAge: 123,
	cacheControl: 456
	}, {
	origin: 'sample.com',
	methods: 'GET',
	credentials: true,
	exposedHeaders: ['zoo', 'bar'],
	allowedHeaders: ['baz', 'foo'],
	maxAge: 321,
	cacheControl: '456'
	}]
	const fastify = Fastify()
	let requestId = 0
	const configDelegation = function (req, cb) {
	// request should have id
	t.ok(req.id)
	// request should not have send
	t.notOk(req.send)
	const config = configs[requestId]
	requestId++
	if (config) {
	cb(null, config)
	} else {
	cb(new Error('ouch'))
	}
	}
	fastify.register(cors, () => configDelegation)
	fastify.get('/', (req, reply) => {
	reply.send('ok')
	})
	fastify.inject({
	method: 'GET',
	url: '/'
	}, (err, res) => {
	t.error(err)
	delete res.headers.date
	t.equal(res.statusCode, 200)
	t.equal(res.payload, 'ok')
	t.match(res.headers, {
	'access-control-allow-origin': 'example.com',
	'access-control-allow-credentials': 'true',
	'access-control-expose-headers': 'foo, bar',
	'content-length': '2'
	})
	t.notMatch(res.headers, { vary: 'Origin' })
	})
	fastify.inject({
	method: 'OPTIONS',
	url: '/',
	headers: {
	'access-control-request-method': 'GET',
	origin: 'example.com'
	}
	}, (err, res) => {
	t.error(err)
	delete res.headers.date
	t.equal(res.statusCode, 204)
	t.equal(res.payload, '')
	t.match(res.headers, {
	'access-control-allow-origin': 'sample.com',
	'access-control-allow-credentials': 'true',
	'access-control-expose-headers': 'zoo, bar',
	'access-control-allow-methods': 'GET',
	'access-control-allow-headers': 'baz, foo',
	'access-control-max-age': '321',
	'cache-control': '456',
	'content-length': '0'
	})
	t.notMatch(res.headers, { vary: 'Origin' })
	})
	fastify.inject({
	method: 'GET',
	url: '/',
	headers: {
	'access-control-request-method': 'GET',
	origin: 'example.com'
	}
	}, (err, res) => {
	t.error(err)
	t.equal(res.statusCode, 500)
	})
	})

But does not add the Vary: origin header.

Steps to Reproduce

add expectation that the vary header exists back to that test (and the other tests with config delegation changed in #288)

Expected Behavior

No response