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kotlinlang

Hey guys I was wondering if this is the place to ask about mongo coroutine driver to be used with Ktor? I'm trying to have a better understanding on how to make the flow results a bit cleaner instead of trying to send an empty list if something is not found and handle that to throw the 404 error

UserRouting
```userRepository.userBy(id)
    .collect { users -&gt;
        if (users.isEmpty()) {
            call.respond(
                status = HttpStatusCode.NotFound,
                message = CallResponse(error = true, message = "User not found")
            )
        } else {
            call.respond(status = HttpStatusCode.OK, message = users)
        }
    }```
The database Flow
```fun obtainUser(id: String): Flow&lt;List&lt;User&gt;&gt; = flow { emit(userCollection.find(filter = Filters.eq(IdField, id)).toList()) }```
if I don't conver it toList it won't let me handle the error which is going to be 404 (which is fine), but I'm building all errors to send the `CallResponse` object as part of the response

I tried with the catch operator and was ignored and even wrapping the routing with a try catch didn't do the work either

I was hoping to get something more like
```userRepository.userBy(id)
    .catch { TODO() }
    .collect { user ->
        call.respond(status = HttpStatusCode.OK, message = users)
    }```

Adjust to your code and test if it works for you. <@U4T0199EC>
```fun Routing.userRoutes(userRepository: UserRepository) {
    get("/users/{id}") {
        val userId = call.parameters["id"]
        if (userId != null) {
            userRepository.obtainUser(userId)
                .collect { users ->
                    if (users.isEmpty()) {
                        call.respond(
                            status = HttpStatusCode.NotFound,
                            message = CallResponse(error = true, message = "User not found")
                        )
                    } else {
                        call.respond(status = HttpStatusCode.OK, message = users)
                    }
                }
        } else {
            call.respond(HttpStatusCode.BadRequest, "Invalid user ID")
        }
    }
}```

I actually check for the parameter like this

```val id: String = call.parameters["id"] ?: return@get call.respond(
    status = HttpStatusCode.BadRequest,
    message = CallResponse(error = true, message = "Id parameter not found")
)```


```fun Routing.userRoutes(userRepository: UserRepository) {
    get("/users/{id}") {
        val id: String = call.parameters["id"] ?: return@get call.respond(
            status = HttpStatusCode.BadRequest,
            message = CallResponse(error = true, message = "Id parameter not found")
        )
        
        userRepository.obtainUser(id)
            .collect { users -&gt;
                if (users.isEmpty()) {
                    call.respond(
                        status = HttpStatusCode.NotFound,
                        message = CallResponse(error = true, message = "User not found")
                    )
                } else {
                    call.respond(status = HttpStatusCode.OK, message = users)
                }
            }
    }
}```