some new endpoints and static serving for media

backend/src/middlewares/existance.ts

@@ -6,12 +6,20 @@ import { Post } from "../entity/Post";
 const userShouldExist = async (req: Request, res: Response, next: NextFunction): Promise<void> => {
     const { username } = req.body;
     const { userId } = req.params;
-
-    if (!(await AppDataSource.manager.findOneBy(User, {
-        username
-    })) || !(await AppDataSource.manager.findOneBy(User, {
-        id: Number.parseInt(userId)
-    }))) {
+    let user;
+    if (username) {
+        user = await AppDataSource.manager.findOneBy(User, {
+            username
+        });
+    } else if (Number.parseInt(userId)) {
+        user = await AppDataSource.manager.findOneBy(User, {
+            id: Number.parseInt(userId)
+        });
+    } else {
+        res.status(404).send("User does not exist.");
+        return;
+    }
+    if (!user) {
         res.status(404).send("User does not exist.");
         return;
     }