Remove duplicated checks and constants across the packages

packages/relay/src/handler.ts

@@ -94,10 +94,14 @@ export function createRelay(options: RelayOptions): (request: Request) => Promis
       fail(403, "FORBIDDEN", "This creation key is not valid.");
   }
 
+  async function checkAdminToken(token: string, s: SessionRow) {
+    if (!safeEqual(await sha256(token), s.adminHash)) fail(403, "FORBIDDEN", "This management key is not valid.");
+  }
+
   async function asAdmin(request: Request, sessionId: string): Promise<SessionRow> {
     const token = bearer(request);
     const s = await loadSession(sessionId);
-    if (!safeEqual(await sha256(token), s.adminHash)) fail(403, "FORBIDDEN", "This management key is not valid.");
+    await checkAdminToken(token, s);
     return s;
   }
 
@@ -191,7 +195,7 @@ export function createRelay(options: RelayOptions): (request: Request) => Promis
     const token = bearer(request);
     const s = await store.getSession(sessionId);
     if (!s) return empty();
-    if (!safeEqual(await sha256(token), s.adminHash)) fail(403, "FORBIDDEN", "This management key is not valid.");
+    await checkAdminToken(token, s);
     await store.deleteSession(sessionId);
     return empty();
   }
@@ -221,7 +225,8 @@ export function createRelay(options: RelayOptions): (request: Request) => Promis
     });
   }
 
-  const refuseDraft = (s: SessionRow, r: SlotRow) => {
+  // Nothing more can be written once a response is submitted or the session is closed.
+  const refuseWrite = (s: SessionRow, r: SlotRow) => {
     if (r.submission !== null) fail(409, "ALREADY_SUBMITTED", "This response has already been submitted.");
     if (s.closedAt !== null) fail(409, "SESSION_CLOSED", "This activity is closed.");
   };
@@ -231,13 +236,13 @@ export function createRelay(options: RelayOptions): (request: Request) => Promis
     const { data } = await readBody(request, bodyLimit);
     const envelope = envelopeField(data.envelope, limits.maxEnvelopeBytes);
     const baseVersion = intField(data.baseVersion, 0, Number.MAX_SAFE_INTEGER, "baseVersion");
-    refuseDraft(session, slot);
+    refuseWrite(session, slot);
     const updatedAt = clock().toISOString();
     if (await store.writeDraft(sessionId, slotId, envelope, baseVersion, updatedAt))
       return json({ draftVersion: baseVersion + 1, updatedAt });
     const [s, r] = await Promise.all([store.getSession(sessionId), store.getSlot(sessionId, slotId)]);
     if (!s || !r) return notFound();
-    refuseDraft(s, r);
+    refuseWrite(s, r);
     return fail(409, "VERSION_CONFLICT", "This response changed on another device.", { draftVersion: r.draftVersion });
   }
 
@@ -249,8 +254,7 @@ export function createRelay(options: RelayOptions): (request: Request) => Promis
     // An identical retry replays the first result, even after the session closes.
     const settled = (s: SessionRow, r: SlotRow) => {
       if (r.submissionHash !== null && safeEqual(r.submissionHash, hash)) return json({ submittedAt: r.submittedAt });
-      if (r.submission !== null) fail(409, "ALREADY_SUBMITTED", "This response has already been submitted.");
-      if (s.closedAt !== null) fail(409, "SESSION_CLOSED", "This activity is closed.");
+      refuseWrite(s, r);
       return null;
     };
     const early = settled(session, slot);

packages/sealed-envelope/src/envelope.ts

@@ -1,4 +1,4 @@
-import { decoder, encoder, fail, fromBase64url, randomBytes, toBase64url } from "./util.ts";
+import { P256, decoder, encoder, fail, fromBase64url, randomBytes, toBase64url } from "./util.ts";
 import type { Bytes } from "./util.ts";
 import type { ContentKey, RecipientPrivateKey, RecipientPublicKey } from "./keys.ts";
 
@@ -16,7 +16,6 @@ const APP = /^[a-z0-9-]{1,40}$/;
 const ID = /^[A-Za-z0-9_-]{22}$/;
 const CHANNELS = new Set<string>(["definition", "draft", "submission", "shared"]);
 const ALGORITHMS = new Set<string>(["A256GCM", "ECDH-ES+A256GCM"]);
-const P256 = { name: "ECDH", namedCurve: "P-256" } as const;
 const ECDH_INFO = encoder.encode("malverdesoftware-envelope/v1 ECDH-ES+A256GCM");
 
 function additionalData(context: EnvelopeContext): Bytes {

packages/sealed-envelope/src/keys.ts

@@ -1,11 +1,10 @@
-import { EnvelopeError, fail, fromBase64url, randomBytes, toBase64url, encoder } from "./util.ts";
+import { EnvelopeError, P256, fail, fromBase64url, randomBytes, toBase64url, encoder } from "./util.ts";
 import type { Bytes } from "./util.ts";
 
 export type ContentKey = CryptoKey & { readonly __brand: "ContentKey" };
 export type RecipientPublicKey = CryptoKey & { readonly __brand: "RecipientPublicKey" };
 export type RecipientPrivateKey = CryptoKey & { readonly __brand: "RecipientPrivateKey" };
 
-const P256 = { name: "ECDH", namedCurve: "P-256" } as const;
 const TOKEN = /^[A-Za-z0-9_-]{1,256}$/;
 
 export const randomSecret = (): string => toBase64url(randomBytes(32));

packages/sealed-envelope/src/util.ts

@@ -20,6 +20,8 @@ export const fail = (code: EnvelopeErrorCode, message: string): never => {
   throw new EnvelopeError(code, message);
 };
 
+export const P256 = { name: "ECDH", namedCurve: "P-256" } as const;
+
 export const encoder = new TextEncoder();
 export const decoder = new TextDecoder("utf-8", { fatal: true });
 

packages/session-client/src/file.ts

@@ -12,6 +12,7 @@ import {
 import type { Envelope } from "@malverdesoftware/sealed-envelope";
 import { fail } from "./errors.ts";
 import { buildLink, isAllowedUrl } from "./link.ts";
+import { APP, ID, SECRET } from "./patterns.ts";
 import { isObject } from "./transport.ts";
 
 export type ParticipantEntry = {
@@ -54,10 +55,7 @@ export type PrepareInput = {
 export const FORMAT = "malverdesoftware-session/v1";
 export const MAX_PARTICIPANTS = 200;
 const MARKER = "<!-- malverdesoftware-session-data: do not edit below this line -->";
-const APP = /^[a-z0-9-]{1,40}$/;
 const LABEL = /^[A-Za-z0-9 _.-]{1,40}$/;
-const ID = /^[A-Za-z0-9_-]{22}$/;
-const SECRET = /^[A-Za-z0-9_-]{43}$/;
 const PUBLIC_KEY = /^[A-Za-z0-9_-]{87}$/;
 const BASE64URL = /^[A-Za-z0-9_-]+$/;
 const PASSCODE = /^[0-9]{6}$/;

packages/session-client/src/link.ts

@@ -1,20 +1,20 @@
 import { fail } from "./errors.ts";
+import { ID, SECRET } from "./patterns.ts";
 
 export type ParticipantCredentials = { sessionId: string; definitionKey: string; slotSecret: string };
 
-const ID = /^[A-Za-z0-9_-]{22}$/;
-const SECRET = /^[A-Za-z0-9_-]{43}$/;
-
 // Everything secret sits after "#", which browsers never send to servers or in Referer headers.
 export const buildLink = (participantUrl: string, c: ParticipantCredentials) =>
   `${participantUrl}#v1.${c.sessionId}.${c.definitionKey}.${c.slotSecret}`;
 
+export const badLink = (): never => fail("BAD_LINK", "This link is incomplete. Open the full link you were sent.");
+
 export function parseParticipantLink(url: string): ParticipantCredentials {
   const text = typeof url === "string" ? url.trim() : "";
   const fragment = text.includes("#") ? text.slice(text.indexOf("#") + 1) : "";
   const [version, sessionId = "", definitionKey = "", slotSecret = "", ...rest] = fragment.split(".");
   if (version !== "v1" || rest.length || !ID.test(sessionId) || !SECRET.test(definitionKey) || !SECRET.test(slotSecret))
-    fail("BAD_LINK", "This link is incomplete. Open the full link you were sent.");
+    badLink();
   return { sessionId, definitionKey, slotSecret };
 }
 

packages/session-client/src/participant.ts

@@ -10,8 +10,9 @@ import {
 } from "@malverdesoftware/sealed-envelope";
 import type { Channel, Envelope } from "@malverdesoftware/sealed-envelope";
 import { SessionError, fail } from "./errors.ts";
-import { isAllowedUrl } from "./link.ts";
+import { badLink, isAllowedUrl } from "./link.ts";
 import type { ParticipantCredentials } from "./link.ts";
+import { APP } from "./patterns.ts";
 import { defaultStorage, safeStorage } from "./storage.ts";
 import type { KeyValueStorage } from "./storage.ts";
 import { isEnvelope, isObject, shapes, transport } from "./transport.ts";
@@ -48,7 +49,6 @@ type LocalState = {
   submitted?: { body: unknown; submittedAt: string };
 };
 
-const APP = /^[a-z0-9-]{1,40}$/;
 const sameJson = (a: unknown, b: unknown) => JSON.stringify(a) === JSON.stringify(b);
 const isCode = (error: unknown, code: string): error is SessionError => error instanceof SessionError && error.code === code;
 
@@ -71,6 +71,12 @@ function readLocal(text: string | null): LocalState {
   }
 }
 
+// A save the relay did not confirm stays on the device; the app shows why.
+const savedOnDevice = (error: SessionError): SaveResult => ({
+  state: "SAVED_ON_DEVICE",
+  reason: error.details?.reason === "SERVER_ERROR" ? "SERVER_ERROR" : "OFFLINE",
+});
+
 const sealing = (error: unknown): never => {
   if (error instanceof EnvelopeError && error.code === "TOO_LARGE")
     fail("TOO_LARGE", "This response is too large to save. Remove some text and try again.");
@@ -84,15 +90,15 @@ export async function joinSession(credentials: ParticipantCredentials, options:
     fail("BAD_INPUT", "The app name or relay address is not valid.");
   const { sessionId, definitionKey, slotSecret } = credentials;
   const storage = safeStorage(options.storage ?? defaultStorage());
-  const prefix = `malverdesoftware:${app}:${sessionId}:${await hashToken(slotSecret).catch(() => fail("BAD_LINK", "This link is incomplete. Open the full link you were sent."))}`;
+  const prefix = `malverdesoftware:${app}:${sessionId}:${await hashToken(slotSecret).catch(badLink)}`;
   const passcodeKey = `${prefix}:passcode`;
   const stateKey = `${prefix}:state`;
 
   const passcode = options.passcode ?? storage.get(passcodeKey);
   if (!passcode) fail("PASSCODE_REQUIRED", "Enter the six-digit passcode you were sent.");
   const slot = await deriveSlot(slotSecret, passcode!).catch((error: unknown): never => {
     if (error instanceof EnvelopeError && error.code === "BAD_FORMAT") fail("WRONG_PASSCODE", "A passcode is six digits.");
-    if (error instanceof EnvelopeError) fail("BAD_LINK", "This link is incomplete. Open the full link you were sent.");
+    if (error instanceof EnvelopeError) badLink();
     throw error;
   });
   const call = transport(relayUrl, options);
@@ -110,7 +116,7 @@ export async function joinSession(credentials: ParticipantCredentials, options:
   });
 
   const unreadable = (): never => fail("DECRYPT_FAILED", "This activity could not be opened. Check that you used the full link.");
-  const definitionKeyValue = await importContentKey(definitionKey).catch(() => fail("BAD_LINK", "This link is incomplete. Open the full link you were sent."));
+  const definitionKeyValue = await importContentKey(definitionKey).catch(badLink);
   const payload = await open(definitionKeyValue, view.definition, { app, sessionId, channel: "definition" }).catch(unreadable);
   if (!isObject(payload) || payload.v !== 1 || typeof payload.researcherPublicKey !== "string" || !("appDefinition" in payload))
     unreadable();
@@ -171,8 +177,7 @@ export async function joinSession(credentials: ParticipantCredentials, options:
       confirmDraft(saved.draftVersion);
       return { state: "SAVED" };
     } catch (error) {
-      if (isCode(error, "NETWORK"))
-        return { state: "SAVED_ON_DEVICE", reason: error.details?.reason === "SERVER_ERROR" ? "SERVER_ERROR" : "OFFLINE" };
+      if (isCode(error, "NETWORK")) return savedOnDevice(error);
       if (isCode(error, "VERSION_CONFLICT") && error.details?.draftVersion === state.baseVersion + 1) {
         // The outcome of an earlier attempt was unknown; if the stored draft is this one, it was saved.
         const latest = await call("GET", path, { token, check: shapes.view });
@@ -266,8 +271,7 @@ export async function joinSession(credentials: ParticipantCredentials, options:
             await sendSubmission();
             return { state: "SAVED" };
           } catch (error) {
-            if (isCode(error, "NETWORK"))
-              return { state: "SAVED_ON_DEVICE", reason: error.details?.reason === "SERVER_ERROR" ? "SERVER_ERROR" : "OFFLINE" };
+            if (isCode(error, "NETWORK")) return savedOnDevice(error);
             throw error;
           }
         }

packages/session-client/src/patterns.ts

@@ -0,0 +1,4 @@
+// Shapes of the identifiers and secrets this package reads. They mirror the relay's and the envelope's own checks.
+export const APP = /^[a-z0-9-]{1,40}$/;
+export const ID = /^[A-Za-z0-9_-]{22}$/;
+export const SECRET = /^[A-Za-z0-9_-]{43}$/;

packages/ui/src/controls.tsx

@@ -30,6 +30,9 @@ export function ErrorMessage({ error }: { error: string }) {
   ) : null;
 }
 
+/** For screens people tap: 44px buttons. */
+const touchSize = (touch: boolean | undefined) => (touch ? { height: ControlsHeight.L, className: "touch-button" } : {});
+
 /** A Ring button that opens a file picker. */
 export function FileButton({ accept, icon, onPick, children }: {
   accept: string;
@@ -73,7 +76,7 @@ export function ConfirmDialog({ show, title, confirmLabel, cancelLabel = "Cancel
   onCancel: () => void;
   children: ReactNode;
 }) {
-  const size = touch ? { height: ControlsHeight.L, className: "touch-button" } : {};
+  const size = touchSize(touch);
   return (
     <Dialog
       show={show}
@@ -117,7 +120,7 @@ export function ConfirmButton({ label, icon, inline, danger, disabled, touch, on
   children: ReactNode;
 }) {
   const [show, setShow] = useState(false);
-  const size = touch ? { height: ControlsHeight.L, className: "touch-button" } : {};
+  const size = touchSize(touch);
   return (
     <>
       <Button