Vertx: How to verify auth before handle body request?

Question

How to verify auth before handle body request?

I'm using vertx:

vertxVersion = '3.8.3'
implementation "io.vertx:vertx-core:$rootProject.vertxVersion"
implementation "io.vertx:vertx-web:$rootProject.vertxVersion"
implementation "io.vertx:vertx-lang-kotlin:$rootProject.vertxVersion"
implementation "io.vertx:vertx-lang-kotlin-coroutines:$rootProject.vertxVersion"
implementation "io.vertx:vertx-mongo-client:$rootProject.vertxVersion"
implementation "io.vertx:vertx-auth-mongo:$rootProject.vertxVersion"
implementation "io.vertx:vertx-auth-jwt:$rootProject.vertxVersion"

I want to verify auth before handle body request. But I got error java.lang.IllegalStateException: Request has already been read

Reproduce by use delay on suspend function:

router.handler { context ->
            launch {
                context.request().setExpectMultipart(true)
                delay(100) //This line is sample for a verify auth process
                context.next()
            }
        }
        .handler {context ->
            println("2")
            context.request()
                .handler {
                    b -> println("buff ${b.length()}")
                }
                .endHandler {
                    println("end handle")
                    context.success("ok")
                }
        }.baseHandle(
            fn
        ).failureHandler {
            println("fail: ${it.failure()}")
            it.error()
        }

When run delay(100) (this's sample for a verify process), I got the error above. If I comment delay(100), It's will be working fine.

Answer 1

This happens because by the time you auhenticated the request, the content has kept arriving and has been dropped.

You need to invoke context.request().pause() in you first handler and then context.request().resume() when you're ready.

In most cases though it's easier to let the BodyHandler manage payload for you.

Answer 2

Finally, I did solve it.

My router is working with the flows:

router.post("/api/upload/file")
      .baseHandle { checkAuthorization(it) }
      .handleFileUpload { updateFileOnItem(it) }

And Following step:

fun checkAuthorization(context: RoutingContext) {
    val request = context.request()
    val tkCookie = request.getCookie("user")
    ...do something to verify user permission
    request.pause()
    context.next()
    context.request().resume()
}

Next:

fun updateFileOnItem(context: RoutingContext) {
    val file = context.fileUploads()
    ...do something
}

It's working with me. Hope it can be help you. Thanks!