`, favicon, and body of `Root()` to\nmatch your app's existing `index.html`, and stamp anything else your shell\nreferences directly (images, css) with `immutableFileUrl()`.\n\n1. Create `frontend/root.tsx`:\n\n```tsx\n/** @jsxImportSource npm:hono@4/jsx */\nimport { raw } from \"npm:hono@4/html\";\nimport { immutableFileUrl } from \"https://esm.town/v/std/utils/index.ts\";\n\n// The HTML shell for the app. It is never cached, so immutableFileUrl can stamp\n// the current val version into each asset URL — the browser caches those\n// immutably, and publishing the val changes the URLs, refetching exactly once.\nexport function Root() {\n return (\n <>\n {raw(\"<!DOCTYPE html>\")}\n <html lang=\"en\">\n <head>\n <meta charSet=\"UTF-8\" />\n <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\" />\n <title>React Hono Val Town Starter

[{"_1":2,"_3":-5,"_4":-5},"loaderData",{"_5":6,"_7":8,"_9":10},"actionData","errors","root",{"_368":369,"_370":371},"routes/_app.x.$handle.$name",{"_11":12,"_13":14,"_15":16,"_18":19,"_17":-7,"_276":-5,"_20":277,"_22":278,"_279":280,"_281":282,"_26":283,"_24":284,"_285":-5,"_286":-5,"_287":61,"_288":289,"_290":58,"_291":-5,"_292":-5,"_293":294},"routes/_app.x.$handle.$name.branch.$branch.code.$",{"_11":12,"_13":14,"_15":16,"_17":-7,"_18":19,"_20":21,"_22":23,"_24":25,"_26":27,"_28":-5,"_29":-5,"_30":-5,"_31":-5,"_32":-5},"handle","test_account_001","name","discovery-radar","branchName","main","version","path","index.ts","project",{"_33":219,"_13":14,"_45":220,"_221":-5,"_222":61,"_223":224,"_225":224,"_226":227,"_228":-5,"_229":230,"_231":38,"_232":58,"_233":-5,"_234":-5,"_235":79,"_236":237,"_238":239,"_240":241,"_242":243,"_244":-5,"_245":246,"_247":246,"_248":249,"_250":249,"_251":249,"_252":246,"_253":246,"_254":255,"_256":257,"_258":259,"_260":61},"tree",[51,52,53,54,55,56],"file",{"_33":34,"_35":36,"_37":38,"_13":19,"_39":40,"_41":42,"_17":43,"_44":-5,"_45":46,"_47":48,"_49":14,"_18":50},"contents",[],"upstream","pull","ahead","behind","envVars","id","106246c6-5eb1-49a8-896e-0671d8647c82","branchId","dc1f9fe4-aa8c-400d-87f3-9d22e6847153","fileId","01a02a62-92f6-771d-907a-be2483e744c9","content","import { serveImmutableFile } from \"https://esm.town/v/std/utils/index.ts\";\nimport { Context, Hono } from \"npm:hono\";\nimport { getCookie, setCookie } from \"npm:hono/cookie\";\nimport { Root } from \"./frontend/root.tsx\";\nimport { StoredUser, getUser, init, upsertUser } from \"./lib/db.ts\";\nimport { authorizeUrl, exchangeCode } from \"./lib/spotify.ts\";\nimport { computeProfile, discover, updateDiscoveryPlaylist } from \"./lib/taste.ts\";\n\nawait init();\n\nconst app = new Hono();\nconst COOKIE = \"discovery_radar_user\";\n\nasync function getSessionUser(c: Context): Promise {\n const id = getCookie(c, COOKIE);\n return id ? getUser(id) : null;\n}\n\n// Serve the (never-cached) HTML shell at the root\napp.get(\"/\", (c) => c.html(Root()));\n\n// Serve frontend files, cached immutably\napp.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path));\n\n// ---- Spotify OAuth ----\napp.get(\"/auth/login\", (c) => {\n const state = crypto.randomUUID();\n setCookie(c, \"discovery_radar_state\", state, { path: \"/\", httpOnly: true, sameSite: \"Lax\" });\n return c.redirect(authorizeUrl(state));\n});\n\napp.get(\"/auth/callback\", async (c) => {\n const code = c.req.query(\"code\");\n if (!code) return c.text(\"Missing authorization code\", 400);\n try {\n const tokens = await exchangeCode(code);\n const me = await (await fetch(\"https://api.spotify.com/v1/me\", {\n headers: { authorization: `Bearer ${tokens.access_token}` },\n })).json();\n await upsertUser({\n spotifyId: me.id,\n displayName: me.display_name ?? \"Spotify user\",\n accessToken: tokens.access_token,\n refreshToken: tokens.refresh_token ?? \"\",\n expiresAt: Date.now() + tokens.expires_in * 1000,\n });\n setCookie(c, COOKIE, me.id, {\n path: \"/\",\n httpOnly: true,\n sameSite: \"Lax\",\n maxAge: 60 * 60 * 24 * 30,\n });\n return c.redirect(\"/\");\n } catch (e) {\n console.error(\"callback failed\", e);\n return c.text(\"Spotify auth failed: \" + (e as Error).message, 500);\n }\n});\n\napp.post(\"/auth/logout\", (c) => {\n setCookie(c, COOKIE, \"\", { path: \"/\", httpOnly: true, sameSite: \"Lax\", maxAge: 0 });\n return c.redirect(\"/\");\n});\n\n// ---- API ----\napp.get(\"/api/me\", async (c) => {\n const u = await getSessionUser(c);\n return c.json(u ? { connected: true, displayName: u.displayName } : { connected: false });\n});\n\napp.get(\"/api/profile\", async (c) => {\n const u = await getSessionUser(c);\n if (!u) return c.json({ error: \"unauthorized\" }, 401);\n return c.json({ profile: await computeProfile(u) });\n});\n\napp.get(\"/api/discover\", async (c) => {\n const u = await getSessionUser(c);\n if (!u) return c.json({ error: \"unauthorized\" }, 401);\n const profile = await computeProfile(u);\n const obscurity = parseFloat(c.req.query(\"obscurity\") ?? \"\");\n const genre = c.req.query(\"genre\");\n const seed = parseFloat(c.req.query(\"seed\") ?? \"\");\n const picks = await discover(u, profile, {\n obscurity: Number.isFinite(obscurity) ? obscurity : undefined,\n genres: genre ? [genre] : undefined,\n seed: Number.isFinite(seed) ? seed : undefined,\n });\n return c.json({ profile, genres: profile.map((a) => a.label), picks });\n});\n\napp.post(\"/api/save\", async (c) => {\n const u = await getSessionUser(c);\n if (!u) return c.json({ error: \"unauthorized\" }, 401);\n try {\n const body = await c.req.json<{ trackUris: string[] }>();\n const playlistId = await updateDiscoveryPlaylist(u, body.trackUris ?? []);\n return c.json({ ok: true, playlistId });\n } catch (e) {\n const msg = (e as Error).message || \"save failed\";\n console.error(\"save failed:\", e);\n return c.json(\n { ok: false, error: \"Spotify blocked playlist access: \" + msg },\n 502,\n );\n }\n});\n\n// Unwrap and rethrow Hono errors as the original error\napp.onError((err) => Promise.reject(err));\n\nexport default app.fetch;\n","fileType","http",10,"parentId","createdAt",["D",1787421190662],"branchVersion",70,"label",[19],{"_33":202,"_13":203,"_37":204,"_44":-5,"_35":36,"_47":205,"_57":58,"_45":206,"_17":79,"_41":88,"_39":-5,"_60":61,"_49":-5,"_62":207,"_18":208},{"_33":129,"_13":130,"_37":131,"_44":-5,"_35":36,"_47":77,"_57":58,"_45":132,"_17":79,"_41":88,"_39":-5,"_60":61,"_49":-5,"_62":133,"_18":134},{"_33":83,"_13":84,"_37":85,"_44":-5,"_35":36,"_47":86,"_57":58,"_45":87,"_17":79,"_41":88,"_39":-5,"_60":61,"_49":-5,"_62":89,"_18":90},{"_33":74,"_13":75,"_37":76,"_44":-5,"_35":36,"_47":77,"_57":58,"_45":78,"_17":79,"_41":24,"_39":80,"_60":61,"_49":-5,"_62":81,"_18":82},{"_33":65,"_13":66,"_37":67,"_44":-5,"_35":36,"_47":68,"_57":58,"_45":69,"_17":70,"_41":24,"_39":71,"_60":61,"_49":-5,"_62":72,"_18":73},{"_33":34,"_13":19,"_37":38,"_44":-5,"_35":36,"_47":48,"_57":58,"_45":59,"_17":43,"_41":42,"_39":40,"_60":61,"_49":14,"_62":63,"_18":64},"latest",true,["D",1787421190662],"deleted",false,"children",[],[19],"3b240b35-7549-4e28-98dc-b0dbd93fdb6d","README.md","01a02a62-92f6-771d-907a-b81da57860c2",90,["D",1787421893911],7,"# 🎧 Discovery Radar\n\nA personal Spotify discovery app that breaks you out of the same 50 artists.\n\nDiscovery runs on the **Last.fm API** (open, read-only with an API key). It computes\n**your sound profile** from Last.fm genre/mood tags, then crawls the **similar-artist\ngraph** for under-discovered acts (ranked by tag-match and listener-count obscurity).\nBecause you listen on Spotify, the app maps each Last.fm track to a **real Spotify\ntrack URI** (via search) and writes your picks to a **Spotify playlist** — and the\nweekly cron keeps it fresh.\n\n## How it works\n\n```mermaid\ngraph LR\n Browser -->|\"Connect Spotify\"| Hono[\"index.ts
(Hono + OAuth)\"]\n Hono -->|stores tokens| DB[(SQLite)]\n Hono -->|computeProfile + discover| SP[\"Spotify API\"]\n SP -->|top artists + genre search| Hono\n Hono -->|radar data + picks| React[\"React app
(radar charts)\"]\n Cron[\"cron/refresh.ts
(weekly)\"] -->|refresh playlist| SP\n```\n\n- `index.ts` — Hono server: Spotify OAuth, session cookie, `/api/me`,\n `/api/profile`, `/api/discover`, `/api/save`.\n- `lib/spotify.ts` — OAuth + Spotify API client. Used for your top artists\n (discovery seeds), mapping tracks to Spotify URIs, and writing playlists.\n- `lib/lastfm.ts` — Last.fm client: similar artists, tags, listener counts, top tracks.\n- `lib/taste.ts` — taste profile (Last.fm tags), discovery, Spotify playlist writer.\n- `lib/db.ts` — SQLite storage for per-user Spotify tokens + playlist id.\n- `frontend/` — React app with a constellation map + grid views.\n- `cron/refresh.ts` — weekly job that refreshes each user's \"Discovery Radar\"\n playlist (Sundays 12:00 UTC).\n\n## Setup\n\n1. Create a **Last.fm API account** at \n and copy your API key.\n2. Set the Last.fm key below.\n\n👉 Add LASTFM_API_KEY here: https://www.val.town/x/test_account_001/discovery-radar/environment-variables?key=LASTFM_API_KEY\n\n3. Spotify (needed only for your listening): create a Spotify app at\n , add the redirect URI\n `https://discovery-radar.val.run/auth/callback`, and set the two env vars below.\n\n👉 Add SPOTIFY_CLIENT_ID here: https://www.val.town/x/test_account_001/discovery-radar/environment-variables?key=SPOTIFY_CLIENT_ID\n\n👉 Add SPOTIFY_CLIENT_SECRET here: https://www.val.town/x/test_account_001/discovery-radar/environment-variables?key=SPOTIFY_CLIENT_SECRET\n\n`SPOTIFY_REDIRECT_URI` is optional — it defaults to the callback URL above.\n\n4. Open the app, hit **Connect Spotify**, authorize, and your taste profile and\n a galaxy of discovered artists appear. Hit **Save** to write them to a\n private \"Discovery Radar\" Spotify playlist.\n\n## Notes\n\n- **Discovery = Last.fm; playlists = Spotify.** This app's Spotify grant is\n restricted (no audio-features / recommendations / browse), so discovery moved\n entirely to Last.fm's open API. Spotify read is only used for your top\n artists and for mapping tracks to URIs — and Spotify *write* (playlists)\n works fine.\n- Obscurity is driven by Last.fm **listener counts** (logged to a 0–100\n \"Popularity\").\n- The match % is tag overlap with your taste profile; the radar is your tag\n profile vs each artist's tags.\n- The weekly cron refreshes the playlist for every connected user.\n- If \"Save\" errors with \"Spotify blocked playlist access\", the token is missing\n `playlist-modify-*` scopes — disconnect and reconnect Spotify to re-consent.\n",[],[66],"4fe8db74-919d-4686-9be5-883aad74c74f","CHANGELOG.md","01a02a62-92f6-771d-907a-b61ebd4f10fe",1,["D",1787417498284],0,"# Changelog\n\n## 2026-07-30 — Immutable asset caching\n\nFrontend files are now served at version-addressed URLs\n(`/__immutable/45/frontend/index.tsx`) with\n`Cache-Control: public, max-age=31536000, immutable`, so repeat visits load the\nwhole client graph from the browser cache — roughly 3× faster (~665ms → ~157ms\nmeasured). Publishing your val bumps its version, which changes every URL, so\ncaches invalidate automatically. Old-version URLs return 404 after a publish\n(like Next.js build assets); a reload picks up the new version.\n\nWhat changed in the template:\n\n- `frontend/index.html` → [`frontend/root.tsx`](/frontend/root.tsx): the HTML\n shell is now JSX and stamps asset URLs with `immutableFileUrl()`\n- [`index.ts`](/index.ts): serves `Root()` at `/`, and one\n `app.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path))` route\n serves all frontend files\n\n### Upgrading an existing remix\n\nYour copy of this template doesn't update automatically. Two options:\n\n**Minimal (most of the benefit):** point both routes at `serveImmutableFile` —\nyour existing bare URLs redirect into versioned space, the new route serves\nthem, and the whole module graph gets cached (costs one redirect per page view):\n\n```ts\nimport { serveImmutableFile } from \"https://esm.town/v/std/utils/index.ts\";\n\napp.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path));\napp.get(\"/frontend/**/*\", (c) => serveImmutableFile(c.req.path)); // was serveFile\n```\n\n**Full upgrade (also removes the redirect):** three self-contained steps —\nno other files needed. Adjust the ``, favicon, and body of `Root()` to\nmatch your app's existing `index.html`, and stamp anything else your shell\nreferences directly (images, css) with `immutableFileUrl()`.\n\n1. Create `frontend/root.tsx`:\n\n```tsx\n/** @jsxImportSource npm:hono@4/jsx */\nimport { raw } from \"npm:hono@4/html\";\nimport { immutableFileUrl } from \"https://esm.town/v/std/utils/index.ts\";\n\n// The HTML shell for the app. It is never cached, so immutableFileUrl can stamp\n// the current val version into each asset URL — the browser caches those\n// immutably, and publishing the val changes the URLs, refetching exactly once.\nexport function Root() {\n return (\n <>\n {raw(\"<!DOCTYPE html>\")}\n <html lang=\"en\">\n <head>\n <meta charSet=\"UTF-8\" />\n <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\" />\n <title>React Hono Val Town Starter\n