Add /absproxy to remove --proxy-path-passthrough

See https://github.com/cdr/code-server/issues/2222#issuecomment-765235938

Makes way more sense.

src/node/routes/index.ts

@@ -103,8 +103,25 @@ export const register = async (
   app.use("/", domainProxy.router)
   wsApp.use("/", domainProxy.wsRouter.router)
 
-  app.use("/proxy", proxy.router)
-  wsApp.use("/proxy", proxy.wsRouter.router)
+  app.all("/proxy/(:port)(/*)?", (req, res) => {
+    proxy.proxy(req, res)
+  })
+  wsApp.get("/proxy/(:port)(/*)?", (req, res) => {
+    proxy.wsProxy(req as WebsocketRequest)
+  })
+  // These two routes pass through the path directly.
+  // So the proxied app must be aware it is running
+  // under /absproxy/<someport>/
+  app.all("/absproxy/(:port)(/*)?", (req, res) => {
+    proxy.proxy(req, res, {
+      passthroughPath: true,
+    })
+  })
+  wsApp.get("/absproxy/(:port)(/*)?", (req, res) => {
+    proxy.wsProxy(req as WebsocketRequest, {
+      passthroughPath: true,
+    })
+  })
 
   app.use(bodyParser.json())
   app.use(bodyParser.urlencoded({ extended: true }))

src/node/routes/pathProxy.ts

@@ -1,14 +1,13 @@
-import { Request, Router } from "express"
+import { Request, Response } from "express"
+import * as path from "path"
 import qs from "qs"
 import { HttpCode, HttpError } from "../../common/http"
 import { normalize } from "../../common/util"
 import { authenticated, ensureAuthenticated, redirect } from "../http"
-import { proxy } from "../proxy"
-import { Router as WsRouter } from "../wsRouter"
+import { proxy as _proxy } from "../proxy"
+import { WebsocketRequest } from "../wsRouter"
 
-export const router = Router()
-
-const getProxyTarget = (req: Request, passthroughPath: boolean): string => {
+const getProxyTarget = (req: Request, passthroughPath?: boolean): string => {
   if (passthroughPath) {
     return `http://0.0.0.0:${req.params.port}/${req.originalUrl}`
   }
@@ -16,7 +15,13 @@ const getProxyTarget = (req: Request, passthroughPath: boolean): string => {
   return `http://0.0.0.0:${req.params.port}/${req.params[0] || ""}${query ? `?${query}` : ""}`
 }
 
-router.all("/(:port)(/*)?", (req, res) => {
+export function proxy(
+  req: Request,
+  res: Response,
+  opts?: {
+    passthroughPath?: boolean
+  },
+): void {
   if (!authenticated(req)) {
     // If visiting the root (/:port only) redirect to the login page.
     if (!req.params[0] || req.params[0] === "/") {
@@ -28,22 +33,27 @@ router.all("/(:port)(/*)?", (req, res) => {
     throw new HttpError("Unauthorized", HttpCode.Unauthorized)
   }
 
-  if (!req.args["proxy-path-passthrough"]) {
+  if (!opts?.passthroughPath) {
     // Absolute redirects need to be based on the subpath when rewriting.
-    ;(req as any).base = `${req.baseUrl}/${req.params.port}`
+    // See proxy.ts.
+    ;(req as any).base = req.path.split(path.sep).slice(0, 3).join(path.sep)
   }
 
-  proxy.web(req, res, {
+  _proxy.web(req, res, {
     ignorePath: true,
-    target: getProxyTarget(req, req.args["proxy-path-passthrough"] || false),
+    target: getProxyTarget(req, opts?.passthroughPath),
   })
-})
+}
 
-export const wsRouter = WsRouter()
-
-wsRouter.ws("/(:port)(/*)?", ensureAuthenticated, (req) => {
-  proxy.ws(req, req.ws, req.head, {
+export function wsProxy(
+  req: WebsocketRequest,
+  opts?: {
+    passthroughPath?: boolean
+  },
+): void {
+  ensureAuthenticated(req)
+  _proxy.ws(req, req.ws, req.head, {
     ignorePath: true,
-    target: getProxyTarget(req, req.args["proxy-path-passthrough"] || false),
+    target: getProxyTarget(req, opts?.passthroughPath),
   })
-})
+}