feat: forward cookies to websocket proxy (#245)

README.md

@@ -156,7 +156,7 @@ This module has _partial_ support for forwarding websockets by passing a
 [`@fastify/websocket`](https://github.com/fastify/fastify-websocket).
 A few things are missing:
 
-1. forwarding headers as well as `rewriteHeaders`
+1. forwarding headers as well as `rewriteHeaders`. Note: Only cookie headers are being forwarded
 2. request id logging
 3. support `ignoreTrailingSlash`
 

index.js

@@ -90,9 +90,17 @@ function setupWebSocketProxy (fastify, options, rewritePrefix) {
       return
     }
 
+    let optionsWs = {}
+    if (request.headers.cookie) {
+      const headers = { cookie: request.headers.cookie }
+      optionsWs = { ...options.wsClientOptions, headers }
+    } else {
+      optionsWs = options.wsClientOptions
+    }
+
     const url = createWebSocketUrl(request)
 
-    const target = new WebSocket(url, options.wsClientOptions)
+    const target = new WebSocket(url, optionsWs)
 
     fastify.log.debug({ url: url.href }, 'proxy websocket')
     proxyWebSockets(source, target)

test/websocket.js

@@ -7,16 +7,18 @@ const WebSocket = require('ws')
 const { createServer } = require('http')
 const { promisify } = require('util')
 const { once } = require('events')
+const cookieValue = 'foo=bar'
 
 test('basic websocket proxy', async (t) => {
-  t.plan(2)
+  t.plan(3)
 
   const origin = createServer()
   const wss = new WebSocket.Server({ server: origin })
   t.teardown(wss.close.bind(wss))
   t.teardown(origin.close.bind(origin))
 
-  wss.on('connection', (ws) => {
+  wss.on('connection', (ws, request) => {
+    t.equal(request.headers.cookie, cookieValue)
     ws.on('message', (message) => {
       t.equal(message.toString(), 'hello')
       // echo
@@ -35,7 +37,8 @@ test('basic websocket proxy', async (t) => {
   await server.listen(0)
   t.teardown(server.close.bind(server))
 
-  const ws = new WebSocket(`ws://localhost:${server.server.address().port}`)
+  const options = { headers: { cookie: cookieValue } }
+  const ws = new WebSocket(`ws://localhost:${server.server.address().port}`, options)
 
   await once(ws, 'open')