fix(demo): prerender deep routes + derive SMART URLs from origin

The static demo on GitHub Pages was unusable for two reasons:

1. Only the root '/' was prerendered. Direct hits to /demo/patients
   or /demo/playground fell through to the site-level 404.html (which
   is Docusaurus's, not our SPA shell), so deep links 404'd.
   Fix: enable crawlLinks so the prerender follows the navbar links
   and emits patients/index.html and playground/index.html.

2. The OAuth redirect_uri and EHR-launch URL were hardcoded to
   http://localhost:3000. Even after login the callback would try
   to hit a localhost dev server.
   Fix: derive them at runtime from window.location.origin +
   import.meta.env.BASE_URL via getRedirectUri() / getAppLaunchUrl()
   helpers. Works for localhost dev AND for /fhir-dsl/demo without
   any env-var juggling. Env-var overrides still honored.

Also stop overwriting the prerendered index.html in the workflow's
stage step — only 404.html needs the SPA-shell fallback now.

Author: awbx

.github/workflows/deploy-docs.yml

@@ -70,10 +70,11 @@ jobs:
           DEMO_DST=apps/docs/build/demo
           mkdir -p "$DEMO_DST"
           cp -R "$DEMO_SRC"/. "$DEMO_DST"/
-          # GitHub Pages serves /demo/ → /demo/index.html (root-route SPA shell);
-          # /demo/<deep-route> → /demo/404.html (which is the same SPA shell, so the
-          # client-side router handles the deep route after hydration).
-          cp "$DEMO_DST/_shell.html" "$DEMO_DST/index.html"
+          # Prerender already produced index.html for /, /patients, /playground.
+          # Copy _shell.html → 404.html so direct hits to unrendered routes
+          # (e.g. /patients/<id>) still load the SPA shell and let the client
+          # router resolve the deep link. (GitHub Pages's site-level 404
+          # fallback is Docusaurus's, not ours, so per-app 404.html is needed.)
           cp "$DEMO_DST/_shell.html" "$DEMO_DST/404.html"
           echo "demo size: $(du -sh $DEMO_DST | cut -f1)"
 

apps/his-demo/src/lib/smart-config.ts

@@ -9,29 +9,46 @@
  * `/launch` route with `?iss=…&launch=…` populated, and our existing /launch
  * handler runs the full PKCE dance.
  */
+// Resolve the public origin the SPA is served from, including any subpath
+// (e.g. /fhir-dsl/demo/). Used to derive redirect URIs at runtime so the
+// SMART flow works on localhost dev AND on https://awbx.github.io/fhir-dsl/demo
+// without env-var juggling. Only call from client-side code (uses `window`).
+function publicAppUrl(routePath: string): string {
+	const base = import.meta.env.BASE_URL ?? "/";
+	const path = routePath.startsWith("/") ? routePath.slice(1) : routePath;
+	return `${window.location.origin}${base}${path}`;
+}
+
 export const SMART_CONFIG = {
 	/** Smart Health IT's launcher app — entry point for the demo's EHR-launch flow. */
 	launcherUrl:
 		import.meta.env.VITE_SMART_LAUNCHER_URL ?? "https://launch.smarthealthit.org",
 	/** FHIR version the launcher should simulate (must match the sandbox endpoint). */
 	launcherFhirVersion: import.meta.env.VITE_SMART_LAUNCHER_FHIR_VERSION ?? "r4",
 	clientId: import.meta.env.VITE_SMART_CLIENT_ID ?? "fhir-dsl-demo",
-	redirectUri: import.meta.env.VITE_SMART_REDIRECT_URI ?? "http://localhost:3000/callback",
-	/** EHR-launch entry point for our app — where the launcher hands us back. */
-	appLaunchUrl: import.meta.env.VITE_SMART_APP_LAUNCH_URL ?? "http://localhost:3000/launch",
 	scope:
 		import.meta.env.VITE_SMART_SCOPE ??
 		"launch openid fhirUser patient/*.read offline_access",
 	/** Default upstream FHIR for queries after login (R4). */
 	fhirBaseUrl: import.meta.env.VITE_FHIR_BASE_URL ?? "https://hapi.fhir.org/baseR4",
 } as const;
 
+/** OAuth redirect_uri — derived at call-site so it tracks the deployment URL. */
+export function getRedirectUri(): string {
+	return import.meta.env.VITE_SMART_REDIRECT_URI ?? publicAppUrl("callback");
+}
+
+/** EHR-launch entry point — where the launcher hands us back. */
+export function getAppLaunchUrl(): string {
+	return import.meta.env.VITE_SMART_APP_LAUNCH_URL ?? publicAppUrl("launch");
+}
+
 export const TOKEN_STORE_KEY = `user:${SMART_CONFIG.clientId}`;
 
 /** Build the URL the "Login with SMART" button should point at. */
 export function buildLauncherEntryUrl(): string {
 	const params = new URLSearchParams({
-		launch_url: SMART_CONFIG.appLaunchUrl,
+		launch_url: getAppLaunchUrl(),
 		fhir_version: SMART_CONFIG.launcherFhirVersion,
 	});
 	return `${SMART_CONFIG.launcherUrl}/?${params.toString()}`;

apps/his-demo/src/routes/callback.tsx

@@ -2,7 +2,12 @@ import { createFileRoute, useNavigate } from "@tanstack/react-router";
 import { useEffect, useState } from "react";
 import { exchangeCode, type SmartConfiguration } from "@fhir-dsl/smart";
 import { withAbsoluteExpiry } from "@fhir-dsl/smart";
-import { SMART_CONFIG, TOKEN_STORE_KEY, buildLauncherEntryUrl } from "#/lib/smart-config";
+import {
+	SMART_CONFIG,
+	TOKEN_STORE_KEY,
+	buildLauncherEntryUrl,
+	getRedirectUri,
+} from "#/lib/smart-config";
 import { tokenStore } from "#/lib/smart-store";
 import { formatError } from "#/lib/error-toast";
 
@@ -64,7 +69,7 @@ function CallbackPage() {
 				const tokens = await exchangeCode({
 					smartConfig: pending.smartConfig,
 					clientId: SMART_CONFIG.clientId,
-					redirectUri: SMART_CONFIG.redirectUri,
+					redirectUri: getRedirectUri(),
 					code,
 					codeVerifier: pending.codeVerifier,
 				});

apps/his-demo/src/routes/launch.tsx

@@ -7,7 +7,7 @@ import {
 	generateCodeVerifier,
 	generateState,
 } from "@fhir-dsl/smart";
-import { SMART_CONFIG, buildLauncherEntryUrl } from "#/lib/smart-config";
+import { SMART_CONFIG, buildLauncherEntryUrl, getRedirectUri } from "#/lib/smart-config";
 import { formatError } from "#/lib/error-toast";
 
 interface LaunchSearch {
@@ -56,7 +56,7 @@ function LaunchPage() {
 				const authorizeUrl = buildAuthorizeUrl({
 					smartConfig,
 					clientId: SMART_CONFIG.clientId,
-					redirectUri: SMART_CONFIG.redirectUri,
+					redirectUri: getRedirectUri(),
 					scope: SMART_CONFIG.scope,
 					state,
 					codeChallenge,

apps/his-demo/vite.config.ts

@@ -22,7 +22,14 @@ const config = defineConfig({
         tanstackStart({
           spa: {
             enabled: true,
-            prerender: { enabled: true },
+            // crawlLinks follows <a> tags from the SPA shell so the navbar's
+            // /patients and /playground get prerendered as physical
+            // dist/client/<route>/index.html files. Required because GitHub
+            // Pages's 404 fallback is site-level (/fhir-dsl/404.html =
+            // Docusaurus's 404), not per-subdir, so deep links need real
+            // files instead of a SPA-shell fallback. Parameterized routes
+            // (/patients/$id) still only resolve via in-app navigation.
+            prerender: { enabled: true, crawlLinks: true },
           },
         }),
         viteReact(),