blink: redirect on root route (#8029)

* make root route redirect to 301

* use config

* end

* add a comment

bskylink/src/routes/index.ts

@@ -4,6 +4,7 @@ import {AppContext} from '../context.js'
 import {default as createShortLink} from './createShortLink.js'
 import {default as health} from './health.js'
 import {default as redirect} from './redirect.js'
+import {default as root} from './root.js'
 import {default as shortLink} from './shortLink.js'
 import {default as siteAssociation} from './siteAssociation.js'
 
@@ -14,6 +15,7 @@ export default function (ctx: AppContext, app: Express) {
   app = siteAssociation(ctx, app) // GET /.well-known/apple-app-site-association
   app = redirect(ctx, app) // GET /redirect
   app = createShortLink(ctx, app) // POST /link
+  app = root(ctx, app) // GET / (redirect to bsky.app on root)
   app = shortLink(ctx, app) // GET /:linkId (should go last due to permissive matching)
   return app
 }

bskylink/src/routes/root.ts

@@ -0,0 +1,14 @@
+import {Express} from 'express'
+
+import {AppContext} from '../context.js'
+import {handler} from './util.js'
+
+export default function (ctx: AppContext, app: Express) {
+  return app.get(
+    '/',
+    handler(async (_req, res) => {
+      res.setHeader('Location', `https://${ctx.cfg.service.appHostname}`)
+      return res.status(301).end()
+    }),
+  )
+}