fix(header): enable header host to fix mtls for specific case, fix #4034

lib/web/fetch/index.js

@@ -1525,7 +1525,11 @@ async function httpNetworkOrCacheFetch (
     }
   }
 
-  httpRequest.headersList.delete('host', true)
+  // Note: per the Fetch spec, Host is a forbidden request-header and should be
+  // deleted here. However, we preserve a user-provided Host header so that
+  // servers requiring a specific Host value (e.g. without port) can be reached.
+  // The Host header is still set automatically by the Client if not provided.
+  // See: https://github.com/nodejs/undici/issues/4034
 
   //    21. If includeCredentials is true, then:
   if (includeCredentials) {

test/fetch/issue-2318.js

@@ -1,26 +1,98 @@
-'use strict'
-
-const { test } = require('node:test')
-const { once } = require('node:events')
-const { createServer } = require('node:http')
-const { fetch } = require('../..')
-const { closeServerAsPromise } = require('../utils/node-http')
-
-test('Undici overrides user-provided `Host` header', async (t) => {
-  t.plan(1)
-
-  const server = createServer({ joinDuplicateHeaders: true }, (req, res) => {
-    t.assert.strictEqual(req.headers.host, `localhost:${server.address().port}`)
-
-    res.end()
-  }).listen(0)
-
-  t.after(closeServerAsPromise(server))
-  await once(server, 'listening')
-
-  await fetch(`http://localhost:${server.address().port}`, {
-    headers: {
-      host: 'www.idk.org'
-    }
-  })
-})
+'use strict'
+
+const { test } = require('node:test')
+const { once } = require('node:events')
+const { createServer } = require('node:http')
+const { fetch } = require('../..')
+const { closeServerAsPromise } = require('../utils/node-http')
+
+test('Undici preserves user-provided `Host` header', async (t) => {
+  t.plan(1)
+
+  const server = createServer({ joinDuplicateHeaders: true }, (req, res) => {
+    t.assert.strictEqual(req.headers.host, 'www.idk.org')
+
+    res.end()
+  }).listen(0)
+
+  t.after(closeServerAsPromise(server))
+  await once(server, 'listening')
+
+  await fetch(`http://localhost:${server.address().port}`, {
+    headers: {
+      host: 'www.idk.org'
+    }
+  })
+})
+
+test('Undici preserves user-provided `Host` header without port', async (t) => {
+  t.plan(1)
+
+  const server = createServer({ joinDuplicateHeaders: true }, (req, res) => {
+    t.assert.strictEqual(req.headers.host, 'localhost')
+
+    res.end()
+  }).listen(0)
+
+  t.after(closeServerAsPromise(server))
+  await once(server, 'listening')
+
+  await fetch(`http://localhost:${server.address().port}`, {
+    headers: {
+      host: 'localhost'
+    }
+  })
+})
+
+test('Undici sets Host header automatically when not user-provided', async (t) => {
+  t.plan(1)
+
+  const server = createServer({ joinDuplicateHeaders: true }, (req, res) => {
+    t.assert.strictEqual(req.headers.host, `localhost:${server.address().port}`)
+
+    res.end()
+  }).listen(0)
+
+  t.after(closeServerAsPromise(server))
+  await once(server, 'listening')
+
+  await fetch(`http://localhost:${server.address().port}`)
+})
+
+test('Undici preserves user-provided `Host` header with custom domain', async (t) => {
+  t.plan(1)
+
+  const server = createServer({ joinDuplicateHeaders: true }, (req, res) => {
+    t.assert.strictEqual(req.headers.host, 'example.com')
+
+    res.end()
+  }).listen(0)
+
+  t.after(closeServerAsPromise(server))
+  await once(server, 'listening')
+
+  await fetch(`http://localhost:${server.address().port}`, {
+    headers: {
+      host: 'example.com'
+    }
+  })
+})
+
+test('Undici preserves user-provided `Host` header with custom domain and port', async (t) => {
+  t.plan(1)
+
+  const server = createServer({ joinDuplicateHeaders: true }, (req, res) => {
+    t.assert.strictEqual(req.headers.host, 'example.com:8080')
+
+    res.end()
+  }).listen(0)
+
+  t.after(closeServerAsPromise(server))
+  await once(server, 'listening')
+
+  await fetch(`http://localhost:${server.address().port}`, {
+    headers: {
+      host: 'example.com:8080'
+    }
+  })
+})