kotlinlang #ktor

As per: https://kotlinlang.slack.com/archives/C0A974TJ9/p1654555064089159 We encountered similar problems too. We have included Ktor lib in our KMM project, however, we don’t invoke any Ktor related call in our iOS project. App crashed due to

Strings.kt line 296

EXC_BAD_ACCESS KERN_INVALID_ADDRESS 0x0000000000000000

We drilled down the logs on crashlytics a bit, and found that the app crashed during when our class

AnalyticsTracker

was initializing. However,

AnalyticsTracker

didn’t contain any Ktor related code, we are only accessing some constants defined in KMM. And what we found interesting is that we found stacktrace for

com.apple.main-thread

comes in with a little bit variation. You may check the attached stacktrace. Kotlin version: 1.5.31, Ktor version: 1.6.0

Stacktrace for Thread #1

Crashed: Thread
0  9Gag                           0x55f634 kfun:kotlinx.cinterop#<get-cstr>__at__kotlin.String(){}kotlinx.cinterop.CValues<kotlinx.cinterop.ByteVarOf<kotlin.Byte>> + 296 (Strings.kt:296)
1  9Gag                           0x6e595c kfun:io.ktor.utils.io.charsets.CharsetImpl.<init>#internal + 26 (CharsetNative.kt:26)
2  9Gag                           0x6e5788 kfun:io.ktor.utils.io.charsets.Charsets#<init>(){} + 383 (CharsetNative.kt:383)
3  9Gag                           0xa698ec InitSingletonStrict + 4325644524
4  9Gag                           0x947104 __unnamed_2910 + 4324454660
5  9Gag                           0xa74630 Kotlin_initRuntimeIfNeeded + 4325688880
6  9Gag                           0xa7698c (anonymous namespace)::workerRoutine(void*) + 4325697932
7  ???                            0x18251c2c0 (Missing)
8  ???                            0x18251c220 (Missing)
9  ???                            0x18251fcdc (Missing)

com.apple.main-thread_3.txt com.apple.main-thread_2.txt com.apple.main-thread_1.txt

Omer Amiel

07/15/2022, 5:05 AM

Hi, How do I pass an instance of

Gson

in the

ContentNegotiation

block? This doesn’t work:

val gsonInstance: Gson = ...

           install(ContentNegotiation) {
                gson {
                    gsonInstance
                    setPrettyPrinting()
                    setLenient()
                }
            }

John O'Reilly

07/15/2022, 10:15 AM

Writing a test using

HttpClient

and wondering if there should be way of specifying what version of TLS you want to use?

Hamza GATTAL

07/15/2022, 5:09 PM

Hi everyone what is the main cause of this exception kotlinx.coroutines.JobCancellationException: Parent job is Completed; job=JobImpl{Completed}@6be308

Jan

07/15/2022, 5:50 PM

whats a good way to access the location hash thing in a html (like: https://test.com/callback#arg=2, everything after #) in ktor? This doesn't seem to work:

get("/") {
    call.respondText(ContentType.Text.Html) {
        """
            <!DOCTYPE html>
            <html lang="en">
            <head>
                <title>Supabase In App Authentication</title>
            </head>

            <body>
            <script>
                const pairs = location.hash.substring(1).split("&").map(pair => pair.split("="))
            </script>
            </body>
            </html>
        """.trimIndent()
    }
}

Is there a good way without using templates or something?

Mikhail

07/17/2022, 6:11 PM

Does Ktor client support

text/event-stream

Helio

07/18/2022, 7:25 AM

Hello Ktor Team, I was wondering if you could shed some light regarding optimisations for Netty Server. More specifically regarding the number of available connections. We are currently running a Netty Server application within an EC2 instance (c5.large) and I noticed that whenever the upstream takes long to process some of the requests, it looks like Ktor run out of connections and therefore our application can’t receive more load, which results in 504's in the Load Balancer Level Having a look at this channel, I noticed that it was suggested to tweak the following parameters:

/**
         * Size of the queue to store [ApplicationCall] instances that cannot be immediately processed
         */
        public var requestQueueLimit: Int = 16

        /**
         * Number of concurrently running requests from the same http pipeline
         */
        public var runningLimit: Int = 32

I would like to know if you have any suggestion regarding what’s the best approach to test / update these parameters? We are currently running

Ktor 2.0.3

. Thanks for your help.

Hamza Maqsood

07/18/2022, 9:14 PM

has anyone used ktor with pgbouncer?

Júlio Santos

07/18/2022, 9:33 PM

Guys, have you ever experimented with graalvm?

Dean Djermanović

07/19/2022, 10:28 AM

What are the differences between

HttpClient(Android)

and

HttpClient(OkHttp)

with regards to

ktor-client

Andrew Steinmetz

07/20/2022, 12:16 AM

Is there a way to configure the ContentNegotiation plugin on ktor to filter out a particular part of response body before trying to parse it? I'm running into an unusual api that decided to add a random string of characters before the actual json object so it keeps throwing an error trying to parse the object since the few characters before the JSON object make it an invalid structure.

Omer Amiel

07/20/2022, 9:26 AM

Hi, I configured a

CIO

client, and able to use it against the server. issue is I can’t see any logs of those req in Charles/Network inspector, I guess it’s bcs I didn’t configure TLS for the engine. I followed this, but not sure how to provide the

keystore

file. is that the issue? any idea how to solve it? EDIT: I actually think it’s bcs I didn’t config proxy, but having issues there: I added this:

engine {
...
    proxy = ProxyBuilder.http(URLBuilder(host = hostName, protocol = URLProtocol.HTTPS, port = 8080 ).build())
...
}

the req is triggered, but getting t/o, what am I doing wrong?

Alexander Sysoev

07/20/2022, 2:35 PM

Hello! How can i read request body in MockEngine handler?

IsaacMart

07/20/2022, 10:54 PM

Hello guys, I am having a challenge with returning my response sealed class. I think is something to do with serialization but haven't been able to figure it out yet. My error: Problem retrieving User.Try again later! Serializer for class 'Success' is not found. Mark the class as @Serializable or provide the serializer explicitly.

IsaacMart

07/20/2022, 10:56 PM

@Serializable
sealed class Resource<T>(
    val data: T? = null,
    val message: String? = null,
    val token: String? = null
) {
    class Success<T>(data: T?, message: String, token: String? = null) :
        Resource<T>(data, message, token)

    class Error<T>(message: String, data: T? = null, token: String? = null) :
        Resource<T>(data, message, token)
}

Javier

07/21/2022, 12:37 PM

I am getting an issue when combining

MockEngine

with

Json

, but the same exact logic is working when fetching from remote, more info in 🧵

Lidonis Calhau

07/22/2022, 8:32 AM

Is there somewhere an example with resources and JSON together? I could find https://github.com/ktorio/ktor-documentation/tree/2.0.3/codeSnippets/snippets/resource-routing and https://github.com/ktorio/ktor-documentation/tree/2.0.3/codeSnippets/snippets/json-kotlinx

eenriquelopez

07/22/2022, 9:41 AM

Hi Kotliners. Does Ktor support chunk content transmission? I am using

HttpClient(CIO)

, and my client speaks with a server that delivers a chunked JSON. I have been trying to change headers, response model, etc… But it does not seem to help. I am receiving the following error:

NoTransformationFoundException: No transformation found: class io.ktor.utils.io.ByteBufferChannel -> class com.my.class

I have seen this when trying ktor cannot serialize something in the data class, but right now I am using an empty class, which should be “serializable”

Joe Altidore

07/25/2022, 10:00 AM

Hello Kotlin devs, I am trying to install "Koin" for DI. I have added the Koin dependency to my gradle but it doesn't seem to install.

implementation("io.insert-koin:koin-core:3.2")

implementation("io.insert-koin:koin-ktor:3.2")

This block is having an error

install(Koin) {

/*logic here**/ } Unresolved reference: Koin

Piotr Krzemiński

07/25/2022, 10:38 AM

hi, I'm looking for someone with hands-on experience with both Spring/Spring Boot and ktor, willing to share their knowledge on a Tricity Kotlin User Group meetup, in a form of a talk around the beginning of September. Ideally we'd like to see some kind of comparison, strengths and weaknesses, experience from introducing it in production, other observations as well. The important aspect is to show how ktor solves certain problems of Spring and why it's worth to even consider trying it out. If you're interested, please reach out to me 🙂

harry248

07/25/2022, 1:31 PM

Intercepting a request using HttpSend (like in https://ktor.io/docs/http-send.html) , what would be the recommended way to prevent the request from being sent. Throwing an exception?

MJegorovas

07/25/2022, 2:45 PM

Probably a bug, don't know for sure, but when you have request resource like this

@Serializable
@Resource("test/{id}.pdf")
class GetPDF(val parent: Timestamp = Timestamp(), val id: String)

The path parameter doesn't get filled and you get a request like

...test/{id}.pdf?id=1

instead of

.../test/1.pdf

Michael Waitt

07/25/2022, 6:17 PM

Hey folks 👋 Quick question on the new

createApplicationPlugin

API. More info in 🧵.

paw

07/25/2022, 6:18 PM

Hi Is there any way to change the way Ktor encodes spaces in query parameters? By default, it encodes spaces as

in query parameters, which I understand is the general convention. However, the API I have to work with is not particularly well-designed, and so it only accepts

%20

as a space, even in query parameters. Is there any way I can tell Ktor to always encode spaces as

%20

no matter the context? The only solution I’ve found so far is

.encodeURLParameter(spaceToPlus = false)

, but that doesn’t seem to be able to apply to globally apply that property in the ktor instance, as one might do with a user agent, it has to be done manually every time. Is there a better way?

Susmitha Gudapati

07/26/2022, 9:14 PM

Hi, I’m using ktor’s

ParametersBuilder

to build params from JsonObject and I see that double quotes are added to my query params’ values. Can someone help me in correcting or handling this ?

hikamaeng

07/27/2022, 7:06 AM

ktor server template coroutine + R2DBC + and more https://github.com/doohochang/kotlin-server-template

Didier Villevalois

07/28/2022, 3:36 PM

Hi all! It seems the gradle build of Ktor is configured to use a JDK 11. Therefore, the unix domain socket tests (requiring JDK 16+) are never run. How can I force the JDK used for tests to a particular JDK version?

Andrew Steinmetz

07/28/2022, 4:50 PM

Does anybody happen to know what the syntax is to grab the request information from a request already made in the

HttpReceivePipeline.After

to be able update this old plugin to Ktor 2.0? Looking at the old and new versions of Ktor, it looks as if

context.request

is no longer accessible since the type on the receive pipeline is now Unit instead of

HttpClientCall

napperley

08/01/2022, 1:12 AM

A new issue has been created in the Ktor Issue Tracker on missing lifecycle APIs: https://youtrack.jetbrains.com/issue/KTOR-4704/Missing-Lifecycle-APIs-For-Ktor-Server

Title

napperley

08/01/2022, 1:12 AM

A new issue has been created in the Ktor Issue Tracker on missing lifecycle APIs: https://youtrack.jetbrains.com/issue/KTOR-4704/Missing-Lifecycle-APIs-For-Ktor-Server

simon.vergauwen

08/01/2022, 6:51 AM

I’ve actually been working on something specifically for Ktor but it’s leveraging structured concurrency instead. I’m still in the process of writing documentation today, and will make a first stable release this week. https://github.com/arrow-kt/suspendapp There is several ways to leverage it, but together with this ticket it would be really nice since it would allow you to leverage the

emebeddedServer

on the

CoroutineScope

and it will cancel/shutdown gracefully on `SIGINT`/`SIGTERM` etc. Not just playing nice in the terminal, but also playing nice with Kubernetes and containers etc. https://youtrack.jetbrains.com/issue/KTOR-4427/CoroutineScopeembeddedServer-graceful-shutdown

You can also use abstraction such as

Resource

and reason about graceful shutdown in terms of structured concurrency. It’s being developed outside of the Ktor context, since it’s also interesting to use in combination with for example Kafka streaming if you want to guarantee offsets being committed before shutdown on

SIGINT

or another shutdown signal.

https://arrow-kt.io/docs/apidocs/arrow-fx-coroutines/arrow.fx.coroutines/-resource/

You can already try the

alpha

release which is published on Maven Central.

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