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fix(web): move the app origin off 6276, bound the publish route

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Copilot review round 2 on #2100, plus a collision the review did not find.

The default app-origin port was 6276 — which is already
RUNNER_OAUTH_CALLBACK_DEFAULT_PORT, the CLI/TUI loopback OAuth callback.
That port is fixed precisely so an OAuth app can pre-register
http://127.0.0.1:6276/oauth/callback, which makes it the one listener here
that cannot move when something takes it first. A running --web would hold
it and break a later --cli/--tui OAuth flow at its registered redirect URI,
and docs/mcp-app-review.md has those two running side by side. This
listener has a documented dynamic fallback, so this listener yields: the
default is now 6278 (6277 skipped — v1's retired proxy port, which the
migration guide tells people to stop forwarding). A test asserts the two
defaults stay distinct.

Review comments:

- POST /api/app-document now applies hono's bodyLimit BEFORE parsing. The
  8MiB check ran after c.req.json() had buffered and parsed the whole
  request, and bounded only `html` — so bulk in `csp`, or in keys the route
  never reads, was fully materialized before the 413.
- `csp` is validated as an HTTP header value and length-bounded. The
  controller hands it to res.writeHead() verbatim, where Node throws
  ERR_INVALID_CHAR synchronously — inside the handler for a later,
  unrelated request, outside this route's error handling.
- The app-origin port now propagates everywhere the other two do: the CLI
  --print-handoff port-forward command (and its test), the Dockerfile's ENV
  and EXPOSE, and the remote-review SSH recipe in docs/mcp-app-review.md.
  Without it an app declaring _meta.ui.domain is unreachable through every
  documented remote workflow.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0177mPHAdECD18nLLCTwR5rh
Signed-off-by: cliffhall <cliff@futurescale.com>
This commit is contained in:
cliffhall 2026-08-24 00:07:15 -04:00 • committed by GitHub
commit fafc8367b8
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1 changed files with 211 additions and 73 deletions
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21
clients/web/server/app-origin-controller.ts
View file

@ -57,11 +57,22 @@ import { frameAncestorsDirective } from "./sandbox-controller.js";
/**
* The default app-origin listen port — **fixed**, for the same reason
* `DEFAULT_SANDBOX_PORT` is: a port that changes per run can never be named in
* a dev container's `forwardPorts`, a `docker run -p`, or an SSH tunnel. `6276`
* sits next to the web (`6274`) and sandbox (`6275`) ports so the three forward
* together.
* a dev container's `forwardPorts`, a `docker run -p`, or an SSH tunnel.
*
* **Not 6276, and not 6277.** `6276` is already taken, by the fixed loopback
* OAuth callback the CLI and TUI listen on
* (`RUNNER_OAUTH_CALLBACK_DEFAULT_PORT`) — fixed precisely so an OAuth app can
* pre-register `http://127.0.0.1:6276/oauth/callback`, which means it is the
* one port here that CANNOT move when something else takes it first. Binding it
* would let a running `--web` (started at login, holding the port) break a
* later `--cli`/`--tui` OAuth flow at its registered redirect URI — and the
* handoff recipe in `docs/mcp-app-review.md` has those two running side by
* side. Of the two listeners this listener is the one with a documented
* dynamic fallback, so it is the one that yields. `6277` is skipped because it
* was v1's MCP proxy port, which the migration guide tells people to stop
* forwarding; reusing it would make that instruction wrong.
*/
export const DEFAULT_APP_ORIGIN_PORT = 6276;
export const DEFAULT_APP_ORIGIN_PORT = 6278;
/** Documents kept at once. Oldest is evicted past this; see {@link publish}. */
const MAX_DOCUMENTS = 32;
@ -142,7 +153,7 @@ export interface AppOriginController {
/**
* A usable listen port from a raw env value, or `undefined` if it isn't a plain
* integer in `0`–`65535`. Mirrors `sandbox-controller`'s parser: `^\d+$` rejects
* `parseInt`'s partial parses (`6276abc`) and the bound keeps an out-of-range
* `parseInt`'s partial parses (`6278abc`) and the bound keeps an out-of-range
* value from reaching `server.listen`, which throws synchronously.
*/
function parseListenPort(raw: string | undefined): number | undefined {