fix: undici headers

lib/request.js

@@ -5,7 +5,7 @@ const querystring = require('querystring')
 const eos = require('end-of-stream')
 const pump = require('pump')
 const undici = require('undici')
-const { stripHttp1ConnectionHeaders } = require('./utils')
+const { patchUndiciHeaders, stripHttp1ConnectionHeaders } = require('./utils')
 const http2 = require('http2')
 
 const {
@@ -158,7 +158,7 @@ function buildRequest (opts) {
       // using delete, otherwise it will render as an empty string
       delete res.headers['transfer-encoding']
 
-      done(null, { statusCode: res.statusCode, headers: res.headers, stream: res.body })
+      done(null, { statusCode: res.statusCode, headers: patchUndiciHeaders(res.headers), stream: res.body })
     })
   }
 

lib/utils.js

@@ -12,6 +12,31 @@ function filterPseudoHeaders (headers) {
   return dest
 }
 
+// http requires the header to be encoded with latin1
+// undici will convert the latin1 buffer to utf8
+// https://github.com/nodejs/undici/blob/2b260c997ad4efe4ed2064b264b4b546a59e7a67/lib/core/util.js#L216-L229
+// after chaining, the header will be serialised using wrong encoding
+// Buffer.from('', 'latin1').toString('utf8') applied
+//
+// in order to persist the encoding, always encode it
+// back to latin1
+function patchUndiciHeaders (headers) {
+  const headersKeys = Object.keys(headers)
+  const dist = {}
+
+  let header
+  let i
+
+  for (i = 0; i < headersKeys.length; i++) {
+    header = headersKeys[i]
+    if (header.charCodeAt(0) !== 58) { // fast path for indexOf(':') === 0
+      dist[header] = Buffer.from(headers[header]).toString('latin1')
+    }
+  }
+
+  return dist
+}
+
 function copyHeaders (headers, reply) {
   const headersKeys = Object.keys(headers)
 
@@ -74,6 +99,7 @@ function buildURL (source, reqBase) {
 }
 
 module.exports = {
+  patchUndiciHeaders,
   copyHeaders,
   stripHttp1ConnectionHeaders,
   filterPseudoHeaders,

test/undici-chaining.js

@@ -0,0 +1,57 @@
+'use strict'
+
+const t = require('tap')
+const Fastify = require('fastify')
+const get = require('simple-get').concat
+const From = require('..')
+
+const header = 'attachment; filename="år.pdf"'
+
+t.plan(6)
+
+const instance = Fastify()
+t.teardown(instance.close.bind(instance))
+const proxy1 = Fastify()
+t.teardown(proxy1.close.bind(proxy1))
+const proxy2 = Fastify()
+t.teardown(proxy2.close.bind(proxy2))
+
+instance.get('/', (request, reply) => {
+  reply.header('content-disposition', header).send('OK')
+})
+
+proxy1.register(From, {
+  undici: {
+    keepAliveMaxTimeout: 10
+  }
+})
+proxy1.get('/', (request, reply) => {
+  return reply.from(`http://localhost:${instance.server.address().port}`)
+})
+
+proxy2.register(From, {
+  undici: {
+    keepAliveMaxTimeout: 10
+  }
+})
+proxy2.get('/', (request, reply) => {
+  return reply.from(`http://localhost:${proxy1.server.address().port}`)
+})
+
+instance.listen({ port: 0 }, err => {
+  t.error(err)
+
+  proxy1.listen({ port: 0 }, err => {
+    t.error(err)
+
+    proxy2.listen({ port: 0 }, err => {
+      t.error(err)
+
+      get(`http://localhost:${proxy2.server.address().port}`, (err, res, data) => {
+        t.error(err)
+        t.equal(res.statusCode, 200)
+        t.equal(data.toString(), 'OK')
+      })
+    })
+  })
+})