# Next.js course user can manually type in api/users/foo

**URL:** <https://forum.codewithmosh.com/t/next-js-course-user-can-manually-type-in-api-users-foo/22492>\
**Category:** Next.js\
**Created:** [September 13, 2023, 9:16pm UTC](https://forum.codewithmosh.com/t/next-js-course-user-can-manually-type-in-api-users-foo/22492 "2023-09-13T21:16:59Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![isimmons33](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.codewithmosh.com/isimmons33/32/2403_2.png) [@isimmons33](https://forum.codewithmosh.com/u/isimmons33)\
**Post date:** [September 13, 2023, 9:16pm UTC](https://forum.codewithmosh.com/t/next-js-course-user-can-manually-type-in-api-users-foo/22492/1 "2023-09-13T21:16:59Z")

</div>

In the course Mosh fixes the mistake of typing our param id as a number where it is actually a string because it comes from a url param (api/users/1).

There is still an issue and it causes the same critical error from the DB.

The user can manually type in the link api/users/foo

This causes the same issue because parseInt(‘foo’) will return NaN

I don’t know yet if Mosh comes back to it but here is how I fixed it for now.

```js
// abstracted function to return user | null
const getUserById = async (userId: string) => {
  const id = parseInt(userId);

  if (isNaN(id)) return null;

  return await prisma.user.findUnique({
    where: { id },
  });
};

export async function GET(
  request: NextRequest,
  { params: { userId } }: { params: { userId: string } }
) {
  const user = await getUserById(userId);

  if (!user)
    return NextResponse.json({ error: 'User not found' }, { status: 404 });

  return NextResponse.json(user);
}

```

---

<div class="post-metadata">

**Author:** ![isimmons33](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.codewithmosh.com/isimmons33/32/2403_2.png) [@isimmons33](https://forum.codewithmosh.com/u/isimmons33)\
**Post date:** [September 13, 2023, 9:54pm UTC](https://forum.codewithmosh.com/t/next-js-course-user-can-manually-type-in-api-users-foo/22492/2 "2023-09-13T21:54:57Z")

</div>

Sharing my learning experience, you can add methods to the prisma client for specific models or all models  
[Docs Link Add a Custom Method](https://www.prisma.io/docs/concepts/components/prisma-client/client-extensions/model#add-a-custom-method)

So I added this to my client

```js
const prismaClientSingleton = () => {
  return new PrismaClient().$extends({
    model: {
      user: {
        async getUserById(userId: string) {
          const id = parseInt(userId);

          if (isNaN(id)) return null;

          return await prisma.user.findUnique({
            where: { id },
          });
        },
      },
    },
  });
};

```

Need to restart dev server so it will rebuild the client.ts file  
Then call it in the api methods like this

```js
const user = await prisma.user.getUserById(userId);

```

I’m going to update it later to allow for if the param is actually a number type and skip the parseInt part. Then rename it to getById() and have it return entity or null and apply it to all models. That way I have a prisma.model.getById() method which seems to be missing from prisma.

---

<div class="post-metadata">

**Author:** ![isimmons33](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.codewithmosh.com/isimmons33/32/2403_2.png) [@isimmons33](https://forum.codewithmosh.com/u/isimmons33)\
**Post date:** [September 14, 2023, 8:57pm UTC](https://forum.codewithmosh.com/t/next-js-course-user-can-manually-type-in-api-users-foo/22492/3 "2023-09-14T20:57:03Z")

</div>

UPDATE : This is all irrelevant now since the lesson on database adapters where we change everything. Now user id is a string.

Extending prisma client is still interesting but as soon as we added the PrismaAdapter(prisma) part I got a type error because PrismaAdapter expects the type of prisma to be

```auto
PrismaClient<Prisma.PrismaClientOptions, never, DefaultArgs>

```

but the type from extending the client the way I did was different so I had to import those types and cast the client as that type. It made TS happy but I don’t know that it would have worked.

Since none of it is needed now, I’ll experiment later with adding methods.