feat: add option for disabling file downloads (#5055)

* feat(cli): add disable-file-downloads to cli

* feat(e2e): add download test

* feat(e2e): add downloads disabled test

* refactor(e2e): explain how to debug unexpected close

* feat(patches): add disable file downloads

* wip: update diff

* Update src/node/cli.ts

Co-authored-by: Asher <ash@coder.com>

* fixup! add missing common/contextkeys file to patch

* fixup!: update patch

* fixup!: default disable-file-downloads undefined

* fixup!: combine e2e tests

* fixup!: use different test names

* feat: add CS_DISABLE_FILE_DOWNLOADS

* fixup!: make explicit and cleanup test

* fixup!: use beforeEach

Co-authored-by: Asher <ash@coder.com>

src/node/cli.ts

@@ -49,6 +49,7 @@ export interface UserProvidedCodeArgs {
   category?: string
   "github-auth"?: string
   "disable-update-check"?: boolean
+  "disable-file-downloads"?: boolean
 }
 
 /**
@@ -157,6 +158,10 @@ export const options: Options<Required<UserProvidedArgs>> = {
       "Disable update check. Without this flag, code-server checks every 6 hours against the latest github release and \n" +
       "then notifies you once every week that a new release is available.",
   },
+  "disable-file-downloads": {
+    type: "boolean",
+    description: "Disable file downloads from Code.",
+  },
   // --enable can be used to enable experimental features. These features
   // provide no guarantees.
   enable: { type: "string[]" },
@@ -537,6 +542,10 @@ export async function setDefaults(cliArgs: UserProvidedArgs, configArgs?: Config
     args.password = process.env.PASSWORD
   }
 
+  if (process.env.CS_DISABLE_FILE_DOWNLOADS === "1") {
+    args["disable-file-downloads"] = true
+  }
+
   const usingEnvHashedPassword = !!process.env.HASHED_PASSWORD
   if (process.env.HASHED_PASSWORD) {
     args["hashed-password"] = process.env.HASHED_PASSWORD