Good morning. I'm having problems to get my custom plugin interact with the Authentication plugin: I...

# ktor

[Ulrich Winter]

Good morning.
I'm having problems to get my custom plugin interact with the Authentication plugin:
I need the response status code within a on(ResponseBodyReadyForSend) hook.
I can get it from call.response.status() in most cases - but not, when authentication has failed.
In that case, I get a null result. The actual 401 status code seems to be generated somewhere later in the plugin chain.
My custom plugin is installed after the Authentication plugin.
How can I retrieve the real status code which is sent to the client within my custom plugin?

[Aleksei Tirman [JB]]

You can add a handler to the ResponseSent hook to observe the response status:

val plugin = createApplicationPlugin("plugin") {
    on(ResponseSent) { call ->
        println("Intercepted status: ${call.response.status()}")
    }
}

[Ulrich Winter]

my custom plugin needs to modify the response:
It's purpose is to add a header containing a cryptographic signature over some properties of the response (including the response status).
Where is the status code actually determined in case of a failed authentication?

[Aleksei Tirman [JB]]

It's determined in the AuthenticationHook hook

[Aleksei Tirman [JB]]

Then you can use the following code to determine the status:

on(ResponseBodyReadyForSend) { call, content ->
    if (content is UnauthorizedResponse) {
        println(content.status)
    }
}

[Ulrich Winter]

Thanks - that worked!