feat(dev): add config for websocket connection

close vitejs#674, close vitejs#676, close vitejs#652

src/client/client.ts

@@ -1,7 +1,10 @@
 // This file runs in the browser.
 
 // injected by serverPluginHmr when served
+declare const __HOSTNAME__: number
 declare const __PORT__: number
+declare const __PATH__: number
+
 declare const __MODE__: string
 declare const __DEFINES__: Record<string, any>
 ;(window as any).process = {
@@ -32,7 +35,12 @@ console.log('[vite] connecting...')
 declare var __VUE_HMR_RUNTIME__: HMRRuntime
 
 const socketProtocol = location.protocol === 'https:' ? 'wss' : 'ws'
-const socketUrl = `${socketProtocol}://${location.hostname}:${__PORT__}`
+const hostname = __HOSTNAME__ || location.hostname
+const path = __PATH__
+let socketUrl = `${socketProtocol}://${hostname}:${__PORT__}`
+if (path) {
+  socketUrl = socketUrl + '/' + path
+}
 const socket = new WebSocket(socketUrl, 'vite-hmr')
 
 function warnFailedFetch(err: Error, path: string | string[]) {

src/node/config.ts

@@ -163,6 +163,13 @@ export interface SharedConfig {
 }
 
 export interface ServerConfig extends SharedConfig {
+  /**
+   * Configure websocket connection.
+   */
+  socketHost?: string
+  socketPort?: number
+  socketPath?: string
+
   hostname?: string
   port?: number
   open?: boolean

src/node/server/serverPluginClient.ts

@@ -26,7 +26,10 @@ export const clientPlugin: ServerPlugin = ({ app, config }) => {
     if (ctx.path === clientPublicPath) {
       ctx.type = 'js'
       ctx.status = 200
-      ctx.body = clientCode.replace(`__PORT__`, ctx.port.toString())
+      ctx.body = clientCode
+        .replace(`__PORT__`, (config.socketPort || ctx.port).toString())
+        .replace(`__HOSTNAME__`, config.socketHost || 'false')
+        .replace(`__PATH__`, config.socketPath || 'false')
     } else {
       if (ctx.path === legacyPublicPath) {
         console.error(