Hello everyone i am new to ktor and would like to get help a kotlinlang #server

post("api/auth/endpoint") {

// start - block of code that is repeated
  val principal = call.principal<JWTPrincipal>()
        val userId = principal?.getClaim("userId", String::class)
        if (userId == null) {
            call.respond(
                HttpStatusCode.Forbidden,
                CyrCloError(401, "User not authenticated. Please login in again")
            )
            return@post
        }
// end
}


how can this code refactored? because i have been keep repeating that code to my other endpoints

Thanks,

edrd

04/27/2023, 1:24 PM

There are several options, but I think the best one is to use the Authentication plugin: https://ktor.io/docs/authentication.html#authenticate-route

Eman

04/27/2023, 1:44 PM

yes thanks, i am using jwt authentication,

but i want to refactor the block that gets the userId, so that method i can re-use in other routes

edrd

04/27/2023, 2:07 PM

Oh, sorry

You could create an extension function that receives the user, like:

@JvmInline
value class UserId(val value: String)

fun <http://Routing.post|Routing.post>(path: String, handle: (UserId) -> Unit) {
  post(path) {
    val principal = ...
    val userId = ...
    // ... null check + return
    handle(userId)
  }
}

// Then in your routers

post("/api/auth/endpoint") { userId ->
  doSomething(userId)
}

However, if the

userId

claim is always required, you should probably move this check to the

validate

method of the JWT authenticator

Eman

04/27/2023, 3:13 PM

...thanks...i will try your suggestion

call is not available?

edrd

04/27/2023, 5:59 PM

Change handle to

ApplicationCall.(UserId) -> Unit

Actually, there’s a recursion going on

I think

Yep, you need to import Ktor’s `post`…

Eman

04/28/2023, 12:36 PM

image.png

...i don't if this will work?

im ending up extending the ApplicationCall with something like this:

suspend fun ApplicationCall.getUserId(handleUser: (String) -> Unit) {
    val principal = principal<JWTPrincipal>()
    val userId = principal?.getClaim("userId", String::class)
    if (userId == null) {
        respond(
            HttpStatusCode.Forbidden,
            CyrCloError(401, "User not authenticated. Please login in again")
        )
        return@getUserId
    }
    handleUser(userId)
}

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