kotlinlang #ktor

after we got the ability to configure mutual tls with ktor 2.0? I've found a workaround, but I'm not sure if the involved APIs are stable enough to rely on them so it doesn't break during a random update...

intercept(ApplicationCallPipeline.Call) {
    val nettyCall = (call.attributes[baseApplicationResponse.EngineRersponseAttributeKey].call) as NettyApplicationCall
    val sslHandler = nettyCall.context.pipeline().get(SslHandler::class.java)
    try {
        val peerPrincipal = sslHandler.engine().session.peerPrincipal as X500Principal
        call.attributes.put(PeerPrincipalKey, peerPrincipal)
        proceed()
    catch (e: SSLPeerUnverifiedException) {
        return@intercept call.respondText("No client certificate provided", status = HttpStatusCode.BadRequest)
    }
}

I've tried it the other way round too (adding a custom handler to netty), but I couldn't find a way to inject the principal into the ktor call.

Joe Altidore

08/01/2022, 8:54 AM

Hello, I am new to ktor. I have built a restful API service with ktor and is working well when run locally but after deploying to Heroku, I get the error below and I am lost on how to resolve the issue.

Error: A JNI error has occurred, please check your installation and try again

2022-08-01T00:00:03.922254+00:00 app[web.1]: Exception in thread "main" java.lang.UnsupportedClassVersionError: com/impact/ApplicationKt has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0

2022-08-01T00:00:03.922349+00:00 app[web.1]: at java.lang.ClassLoader.defineClass1(Native Method)

2022-08-01T00:00:03.922384+00:00 app[web.1]: at java.lang.ClassLoader.defineClass(ClassLoader.java:756)

2022-08-01T00:00:03.922539+00:00 app[web.1]: at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)

2022-08-01T00:00:03.922575+00:00 app[web.1]: at <http://java.net|java.net>.URLClassLoader.defineClass(URLClassLoader.java:473)

2022-08-01T00:00:03.922623+00:00 app[web.1]: at <http://java.net|java.net>.URLClassLoader.access$100(URLClassLoader.java:74)

2022-08-01T00:00:03.922664+00:00 app[web.1]: at <http://java.net|java.net>.URLClassLoader$1.run(URLClassLoader.java:369)

2022-08-01T00:00:03.922700+00:00 app[web.1]: at <http://java.net|java.net>.URLClassLoader$1.run(URLClassLoader.java:363)

2022-08-01T00:00:03.922740+00:00 app[web.1]: at java.security.AccessController.doPrivileged(Native Method)

2022-08-01T00:00:03.922774+00:00 app[web.1]: at <http://java.net|java.net>.URLClassLoader.findClass(URLClassLoader.java:362)

2022-08-01T00:00:03.922808+00:00 app[web.1]: at java.lang.ClassLoader.loadClass(ClassLoader.java:418)

2022-08-01T00:00:03.922842+00:00 app[web.1]: at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)

2022-08-01T00:00:03.922883+00:00 app[web.1]: at java.lang.ClassLoader.loadClass(ClassLoader.java:351)

2022-08-01T00:00:03.922922+00:00 app[web.1]: at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:601)

Jerry Yion

08/02/2022, 1:46 AM

or one client per request

Rekha

08/01/2022, 7:05 AM

hi, i am a newbie to ktor. We are using kotr for android and trying to write the unit test for ktor network call with okhttp. how to mock the client enginfe for unit test? Thanks

Rohan Maity

08/02/2022, 7:50 AM

hi I am trying to do a redirect like this (using

ktor-server-resources

)

suspend fun ApplicationCall.redirect(resource: Any) {
    val path = application.href(resource)
    respondRedirect(path)
}

And here is the file where redirect is used

const val PHRASES = "/phrases"

@Serializable
@Resource(PHRASES)
class Phrases

fun Route.phrases(db: Repository) {
    authenticate("auth") {
        get<Phrases> {
            val user = call.authentication.principal as User
            val phrases = db.phrases().toTypedArray()
            call.respond(
                FreeMarkerContent(
                    "phrases.ftl",
                    mapOf("phrases" to phrases, "displayName" to user.displayName)
                )
            )
        }

        post<Phrases> {
            val params = call.receiveParameters()
            val action = params["action"] ?: throw IllegalArgumentException("Missing parameter: action")
            when(action) {
                "delete" -> {
                    val id = params["id"] ?: throw IllegalArgumentException("Missing parameter: id")
                    db.remove(id)
                }
                "add" -> {
                    val emoji = params["emoji"] ?: throw IllegalArgumentException("Missing parameter: emoji")
                    val phrase = params["phrase"] ?: throw IllegalArgumentException("Missing parameter: phrase")
                    db.add(EmojiPhrase(emoji, phrase))
                }
            }
            call.redirect(Phrases)
        }
    }
}

Initial page loads fine But on redirect it fails on browser console I see this 405 error Now I am not sure what is wrong here Update Actually on further checking its

POST

method which is not working I am not sure what's wrong when I simply use

post(StringUrl)

it works but when

server-resources

it does not work Solved It was the issue of imports, I used the

<http://server.routing.post|server.routing.post>

instead of

<http://server.resources.post|server.resources.post>

When using

server-resources

plugin in ktor, one needs to use HTTP methods from

server.resources

package and not from

server.routing

package Thanks @Aleksei Tirman [JB] helping me here

mudasar187

08/01/2022, 11:36 AM

Hi! Could people help me with hint of why i should use HOCON file or not and make the config in code? I am new to Ktor and i want to hear some experience from people in here 🙂

Jerry Yion

08/02/2022, 1:45 AM

Hi there! I am just wondering if it is better to create one http client per app…

Ollis

08/02/2022, 8:54 AM

Hi, does anyone have any idea what causes my issue with `kotest`and

ktor

? https://github.com/kotest/kotest/issues/3134

08/02/2022, 9:10 AM

hi there Does ktor client start log request\responses in single log message? I see deference in runtime - but haven’t seen anything about it in documentation and want clarify it any way - like it 😃

ptsiogas

08/02/2022, 10:39 AM

Quick question for mobile client: can I have Ktor version 1.6.7 on a library gradle dependency and Ktor version 2.0.3 on my main project? I have tried it and I realised that those two are not working well together (e.g I got java.lang.NoClassDefFoundError: Failed resolution of: Lio/ktor/client/features/ClientRequestException).

Luiz Aguiar

08/02/2022, 2:46 PM

Hello folks… I'm giving a try to Ktor again and one aspect that still making me wonder, is related a how "properly" design an application without relying in DI. In Quarkus/Spring, you inject component classes in other components (classes) and don't think much about it, it "just works". What might be a good design approach to use in a Ktor application? Thinking that you might have a couple of "components" that might be used for other components and of course you don't want to have multiple instances spread around. I've been trying to use mostly independent functions, but not sure how "scalable" is this in a big application. Cheers 👋

Sunny

08/03/2022, 7:04 AM

Hi guys, post upgrade from 1.6 to 2.0 , running into an error, calls fail with Serializer for class 'JsonLiteral' is not found.
Mark the class as @Serializable or provide the serializer explicitly.HttpClientUtils
Request is of type

JsonElement

. Anyone faced something similar / any leads to look into.

cafonsomota

08/03/2022, 4:57 PM

hello all! I’ve noticed something quite odd in a request client side. I’m using ktor in a multiplatform project (android/ios) and I’m sending an object with latitude/longitude (defined as double). If their value is 0.0, they’re not sent, if it’s a different value it is. Anything I might be doing wrong?

FunkyMuse

08/03/2022, 5:33 PM

hello guys, does anyone have or had come across a sample project using resilience4j with ktor, especially circuit breaker and rate limiter?

Chad Gregory

08/04/2022, 4:19 PM

Hey everyone! I'm looking for some help with setting up my ktor client. I am storing the url in a proto datastore and I'm not sure how to get it out of there and into the

defaultRequest

block. has anyone else did this? How did you go about it?

MJegorovas

08/05/2022, 7:02 AM

How about using defaultRequest ?

Rohde Fischer

08/05/2022, 12:32 PM

using KTor sockets on native, how would I go about creating a connection timeout? It seems that the

socketTimeout

has no effect, and my socket just keeps waiting, and I cannot find any parameters or settings for that

PoisonedYouth

08/07/2022, 11:57 AM

Hey guys, does Ktor support deserialization of form data to object (when using together with Thymeleaf) out of the box or is it necessary to write custom mapper? I installed content negotiation with Jackson but always get an exception (io.ktor.request.CannotTransformToTypeException).

Joe Altidore

08/07/2022, 2:11 PM

Hello guys. I am using ktor client and I can't find a way to handle response error.

Rohde Fischer

08/07/2022, 2:56 PM

And another curious question about KTor sockets, apart from the apparently non-existing timeout, how am I supposed to test sockets in a reasonable way? Seems the only way I can find is to wrap the static methods in interfaces so, I can inject test-implementations - but I assume that KTor sockets isn't designed in the non-testable fashions that 10+ years of programming experience have shown us to be bad design?

Trey

08/08/2022, 8:59 PM

Can somebody point me to an example project or documentation that shows how to use Ktor's websocket functionality in a project? I've seen the simple example for the client/server chat example, but it doesn't seem to be a best practice when you need to send messages across the web socket from your app. Providing the incoming messages to your app as a flow seems ideal, but the sending pattern is what I'm curious about. Especially if the web socket is considered a "source" that is encapsulated inside of a "repository".

Marc Knaup

08/09/2022, 9:28 AM

Anyone ever had a

UTF-8 is not supported.

exception when using

Url(String)

constructor on K/JS? I’m trying to figure out why it’s not working 😞 I’m on Cloudflare Workers.

Ovsyannikov Alexey

08/09/2022, 5:56 PM

Hello 🙂 Is it possible in ktor clients to change default request url on the fly (after config) ?

Nick Halase

08/10/2022, 4:27 PM

Does the ktor-client ContentNegotiation plugin automatically add all registered types to the Accept header? I'm not configuring defaultRequest on my client, but when I make a request with the httpClient.get (i'm also using the Resources plugin for type-safe routing), and I log out the

call.request.accept()

value, it's a CSV of content types.

amadeu01

08/11/2022, 8:46 AM

hey, do you know good ktor open source projects ?

Didier Villevalois

08/11/2022, 8:54 AM

[ktor-network/ktor-io question] It seems that

io.ktor.utils.io.ByteBufferChannel

reuses the`kotlinx.coroutines.channels.ClosedReceiveChannelException` exception to signal all its EOF errors. It is quite confusing and hard to

catch

when you use both `Channel`s and `ByteBufferChannel`s in the same coroutines. Shouldn't

ByteBufferChannel

use a custom exception inheriting from

IOException

? Should I open a YT issue?

Mati Galli

08/11/2022, 7:02 PM

Hi guys! I’m migrating my project to ktor 2.0 with kotlin 1.7 and I’m having troubles with a

test task

configured on my

build.gradle.kts

. It seems that the tests are passing, but an exception is thrown anyway

08/11/2022, 7:34 PM

I'm using ktor 2.0.3 in my Android app with the CIO engine. I've found that in the emulator I get a crash when trying to make a request to

<https://youtube.com>

but not when I make a request to another URL such as

<https://github.com>

On an actual phone this crash doesn't happen. The code im using is this in my MainActivity

HttpClient(CIO).get("<https://youtube.com/>")

The crash

Caused by: java.net.SocketException: Network is unreachable
	at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
	at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:762)
	at io.ktor.network.sockets.SocketImpl.connect$ktor_network(SocketImpl.kt:50)
	at io.ktor.network.sockets.SocketImpl$connect$1.invokeSuspend(Unknown Source:15)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
	at kotlinx.coroutines.internal.LimitedDispatcher.run(LimitedDispatcher.kt:42)
	at kotlinx.coroutines.scheduling.TaskImpl.run(Tasks.kt:95)
	at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:570)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:749)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:677)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:664)

Lucas

08/12/2022, 3:34 AM

Im using ktor client to call this API which needs basic authorization. My application has credentials for several users of this API, and i need to change the auth header for each different user. Initially i thought about using the same HttpClient and change the header on each request, but i didnt find a way to do so (using the basic auth plugin). Should i be using different clients for each user? I feel like this could be expensive and if i could reuse the clients it would be much better. Or should i just be setting the header manually on each request, and stop using the basic auth plugin?

hhariri

08/12/2022, 9:19 AM

📣 Ktor 2.1.0 with a bunch of new tools released! 📣 https://blog.jetbrains.com/ktor/2022/08/12/ktor-2-1-0-released-and-it-comes-with-goodies/