v3: added opengraph support to the app, wrote README instructions incl. a Docker image

api/main.ts

@@ -13,16 +13,27 @@ import followsRouter from "./routes/follows.ts";
 import notificationsRouter from "./routes/notifications.ts";
 import invitesRouter from "./routes/invites.ts";
 
-import { BASE_URL, HOSTNAME, PORT } from "./config.ts";
+import { ALLOWED_ORIGINS, BASE_URL, LISTEN_HOST, PORT } from "./config.ts";
 import { errorMiddleware } from "./middleware/error.ts";
-import routeStaticFilesFrom from "./lib/static.ts";
-import { DUMPS_DIR, UPLOADS_DIR } from "./lib/upload.ts";
-import { UUID_RE } from "./lib/slugify.ts";
+import { ogMiddleware } from "./middleware/og.ts";
+import { routeStaticFilesFrom } from "./lib/static.ts";
 
 const app = new Application();
 
+const cors = oakCors({ origin: ALLOWED_ORIGINS });
+
 app.use(errorMiddleware);
-app.use(oakCors());
+app.use(ogMiddleware);
+// Only invoke oakCors when the origin is present and allowed.
+// The library calls next() without await when origin is falsy, which
+// corrupts the response in Oak's async middleware chain.
+app.use(async (ctx, next) => {
+  const origin = ctx.request.headers.get("origin");
+  if (origin && ALLOWED_ORIGINS.includes(origin)) {
+    return await cors(ctx, next);
+  }
+  await next();
+});
 app.use(
   dumpsRouter.routes(),
   dumpsRouter.allowedMethods(),
@@ -82,22 +93,8 @@ app.addEventListener(
   (e) => console.log(`Uncaught error: ${e.message}`),
 );
 
-// Migrate dump files from uploads root to uploads/dumps subfolder
-async function migrateDumpFiles() {
-  await Deno.mkdir(DUMPS_DIR, { recursive: true });
-  for await (const entry of Deno.readDir(UPLOADS_DIR)) {
-    if (entry.isFile && UUID_RE.test(entry.name)) {
-      await Deno.rename(
-        `${UPLOADS_DIR}/${entry.name}`,
-        `${DUMPS_DIR}/${entry.name}`,
-      ).catch(() => {});
-    }
-  }
-}
-
 if (import.meta.main) {
-  await migrateDumpFiles();
-  await app.listen({ hostname: HOSTNAME, port: PORT });
+  await app.listen({ hostname: LISTEN_HOST, port: PORT });
 }
 
 export { app };