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perf(proxy): pre-compile context matchers at server creation #23263

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Merged
sapphi-red merged 2 commits into from
Sep 10, 2026
Merged

perf(proxy): pre-compile context matchers at server creation #23263

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2ae17df
perf(proxy): pre-compile context matchers at server creation
btea Aug 14, 2026
b7b9c40
Merge branch 'main' into refactor/proxy-middleware
btea Sep 8, 2026
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39 changes: 26 additions & 13 deletions packages/vite/src/node/server/middlewares/proxy.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -72,13 +72,29 @@ const rewriteOriginHeader = (
}
}

type ProxyContextEntry = {
proxy: httpProxy.ProxyServer
options: ProxyOptions
// Pre-compiled context matcher. Regex contexts are compiled once at server
// creation instead of being re-parsed on every request.
match: (url: string) => boolean
}

function createProxyContextMatcher(context: string): (url: string) => boolean {
if (context[0] === '^') {
const regex = new RegExp(context)
return (url) => regex.test(url)
}
return (url) => url.startsWith(context)
}

export function proxyMiddleware(
httpServer: HttpServer | null,
options: NonNullable<CommonServerOptions['proxy']>,
config: ResolvedConfig,
): Connect.NextHandleFunction {
// lazy require only when proxy is used
const proxies: Record<string, [httpProxy.ProxyServer, ProxyOptions]> = {}
const proxies: Record<string, ProxyContextEntry> = {}

Object.keys(options).forEach((context) => {
let opts = options[context]
Expand Down Expand Up @@ -135,15 +151,19 @@ export function proxyMiddleware(
})

// clone before saving because http-proxy mutates the options
proxies[context] = [proxy, { ...opts }]
proxies[context] = {
proxy,
options: { ...opts },
match: createProxyContextMatcher(context),
}
})

if (httpServer) {
httpServer.on('upgrade', async (req, socket, head) => {
const url = req.url!
for (const context in proxies) {
if (doesProxyContextMatchUrl(context, url)) {
const [proxy, opts] = proxies[context]
const { proxy, options: opts, match } = proxies[context]
if (match(url)) {
if (
opts.ws ||
opts.target?.toString().startsWith('ws:') ||
Expand Down Expand Up @@ -190,8 +210,8 @@ export function proxyMiddleware(
return async function viteProxyMiddleware(req, res, next) {
const url = req.url!
for (const context in proxies) {
if (doesProxyContextMatchUrl(context, url)) {
const [proxy, opts] = proxies[context]
const { proxy, options: opts, match } = proxies[context]
if (match(url)) {
const options: httpProxy.ServerOptions = {}

if (opts.bypass) {
Expand Down Expand Up @@ -227,10 +247,3 @@ export function proxyMiddleware(
next()
}
}

function doesProxyContextMatchUrl(context: string, url: string): boolean {
return (
(context[0] === '^' && new RegExp(context).test(url)) ||
url.startsWith(context)
)
}