From ab666ec2a4835ad2bb715ee288a06dca7b6f16ef Mon Sep 17 00:00:00 2001
From: Mike Ledger <eleventynine@gmail.com>
Date: Fri, 17 Sep 2021 00:12:26 +1000
Subject: [PATCH] fix: websocket proxies not the same as http (#4893)

---
 .../vite/src/node/server/middlewares/proxy.ts    | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/packages/vite/src/node/server/middlewares/proxy.ts b/packages/vite/src/node/server/middlewares/proxy.ts
index f23237d0c7852f..b8c653fdfb4eda 100644
--- a/packages/vite/src/node/server/middlewares/proxy.ts
+++ b/packages/vite/src/node/server/middlewares/proxy.ts
@@ -62,7 +62,7 @@ export function proxyMiddleware(
     httpServer.on('upgrade', (req, socket, head) => {
       const url = req.url!
       for (const context in proxies) {
-        if (url.startsWith(context)) {
+        if (doesProxyContextMatchUrl(context, url)) {
           const [proxy, opts] = proxies[context]
           if (
             (opts.ws || opts.target?.toString().startsWith('ws:')) &&
@@ -71,7 +71,9 @@ export function proxyMiddleware(
             if (opts.rewrite) {
               req.url = opts.rewrite(url)
             }
+            debug(`${req.url} -> ws ${opts.target}`)
             proxy.ws(req, socket, head)
+            return
           }
         }
       }
@@ -82,10 +84,7 @@ export function proxyMiddleware(
   return function viteProxyMiddleware(req, res, next) {
     const url = req.url!
     for (const context in proxies) {
-      if (
-        (context.startsWith('^') && new RegExp(context).test(url)) ||
-        url.startsWith(context)
-      ) {
+      if (doesProxyContextMatchUrl(context, url)) {
         const [proxy, opts] = proxies[context]
         const options: HttpProxy.ServerOptions = {}
 
@@ -116,3 +115,10 @@ export function proxyMiddleware(
     next()
   }
 }
+
+function doesProxyContextMatchUrl(context: string, url: string): boolean {
+  return (
+    (context.startsWith('^') && new RegExp(context).test(url)) ||
+    url.startsWith(context)
+  )
+}