Only serve HTML on specific index.html requests

Otherwise there is risk of an infinite loop through the iframe where the
fallback keeps loading the root HTML which itself has an iframe...

src/node/app/server.tsx

@@ -3,6 +3,7 @@ import * as http from "http"
 import * as React from "react"
 import * as ReactDOMServer from "react-dom/server"
 import App from "../../browser/app"
+import { HttpCode, HttpError } from "../../common/http"
 import { Options } from "../../common/util"
 import { HttpProvider, HttpResponse, Route } from "../http"
 
@@ -21,6 +22,9 @@ export class MainHttpProvider extends HttpProvider {
       }
 
       case "/": {
+        if (route.requestPath !== "/index.html") {
+          throw new HttpError("Not found", HttpCode.NotFound)
+        }
         const options: Options = {
           authed: !!this.authenticated(request),
           basePath: this.base(route),

src/node/vscode/server.ts

@@ -11,6 +11,7 @@ import {
   VscodeOptions,
   WorkbenchOptions,
 } from "../../../lib/vscode/src/vs/server/ipc"
+import { HttpCode, HttpError } from "../../common/http"
 import { generateUuid } from "../../common/util"
 import { HttpProvider, HttpProviderOptions, HttpResponse, Route } from "../http"
 import { SettingsProvider } from "../settings"
@@ -114,6 +115,9 @@ export class VscodeHttpProvider extends HttpProvider {
     this.ensureAuthenticated(request)
     switch (route.base) {
       case "/":
+        if (route.requestPath !== "/index.html") {
+          throw new HttpError("Not found", HttpCode.NotFound)
+        }
         try {
           return await this.getRoot(request, route)
         } catch (error) {