kotlinlang #ktor

When using Ktor as a client, if I do 2 requests in two different Coroutines for the same client in parallel, are they executed in parallel or does the client force them to run sequentially? I'm asking because my stdout output looks very sequential (no mess because of lines being printed one inside the other), so I'm wondering.

Jamy

04/14/2020, 12:16 PM

Hello, any of you already deployed a ktor service with environment variables on Google App Engine from Google Cloud Platform? If possible without saving the variables in a file on git (security issue)

gotoOla

04/14/2020, 12:27 PM

Hi! Does anyone know how Ktor is utilizing thread pools (call thread pool and worker thread pool) when working with Netty as its engine?

Sam Garfinkel

04/15/2020, 3:52 PM

Why can’t

io.ktor.client.features.json.JsonSerializer.read(..)

return the nullable

Any?

and why can’t the

write

function accept

Any?

? Is this just how they were designed, or is there an actual implementation constraint?

Marek

04/16/2020, 6:38 PM

Hello everybody! 🙂 I'm qa engineer and I'm using one of sample ktor apps to practice new tool for performance testing using Locust. To training I'm using Kweet app https://github.com/ktorio/ktor-samples/tree/master/app/kweet I have a problem with database. I see it's h2 database stored in file. So I wrote a test script to create some users and kweets and I want to clear database after my tests. Could you guys help me with connection to DB? What I want to do is to execute some sql queries for example delete * from users, delete * from kweets. What's the address of h2 db and credentials in kweet app? We can assume that I'm running my python script from the main catalog of kweet app Maybe I should change some code to enable DB to be visible and connectable?

christophsturm

04/17/2020, 7:49 AM

if I have jackson support installed, can i use it only for replies, but still set the post body of my request as normal string or byte array? also I have logging installed but it does not seem to log my outgoing requests and post bodies

Maurice Wingbermuhle

04/17/2020, 8:42 AM

I\KtorHttpClient: REQUEST OBFUSCATED_URL failed with exception: kotlin.native.concurrent.InvalidMutabilityException: mutation attempt of frozen kotlinx.coroutines.InvokeOnCompletion@847c8
I\KtorHttpClient: REQUEST OBFUSCATED_URL failed with exception: kotlin.native.concurrent.InvalidMutabilityException: mutation attempt of frozen io.ktor.util.pipeline.SuspendFunctionGun@596c8
kotlinx.coroutines.CoroutinesInternalError: Fatal exception in coroutines machinery for DispatchedContinuation[DispatchQueue@1517388, Continuation @ $runAsync$lambda-1COROUTINE$200]. Please read KDoc to 'handleFatalException' method and report this incident to maintainers
        at 0   myLib                               0x00000001060ceb13 kfun:kotlin.Error.<init>(kotlin.String?;kotlin.Throwable?)kotlin.Error + 115 (/Users/teamcity1/teamcity_work/4d622a065c544371/runtime/src/main/kotlin/kotlin/Exceptions.kt:14:63)
        at 1   myLib                               0x0000000106629ad3 kfun:kotlinx.coroutines.CoroutinesInternalError.<init>(kotlin.String;kotlin.Throwable)kotlinx.coroutines.CoroutinesInternalError + 115 (/opt/buildAgent/work/44ec6e850d5c63f0/kotlinx-coroutines-core/common/src/Exceptions.common.kt:28:77)
        at 2   myLib                               0x00000001067676ca kfun:kotlinx.coroutines.DispatchedTask.handleFatalException$kotlinx-coroutines-core(kotlin.Throwable?;kotlin.Throwable?) + 938 (/opt/buildAgent/work/44ec6e850d5c63f0/kotlinx-coroutines-core/common/src/internal/DispatchedTask.kt:93:22)
        at 3   myLib                               0x00000001067672b4 kfun:kotlinx.coroutines.DispatchedTask.run() + 3156 (/opt/buildAgent/work/44ec6e850d5c63f0/kotlinx-coroutines-core/common/src/internal/DispatchedTask.kt:64:13)
        at 4   myLib                               0x0000000105d93f35 kfun:ob.fus.client.utils.DispatchQueue.dispatch$lambda-0#internal + 85 (/Path-at-my-machine/myLib/src/iosMain/kotlin/ob/fus/client/utils/Dispatchers.kt:24:19)
        at 5   myLib                               0x0000000105d9401b kfun:io.hsdp.client.utils.DispatchQueue.$dispatch$lambda-0$FUNCTION_REFERENCE$492.invoke#internal + 59 (/Path-at-my-machine/myLib/src/iosMain/kotlin/ob/fus/client/utils/Dispatchers.kt:23:39)
        at 6   myLib                               0x0000000105d9407b kfun:io.hsdp.client.utils.DispatchQueue.$dispatch$lambda-0$FUNCTION_REFERENCE$492.$<bridge-UNN>invoke()#internal + 59 (/Path-at-my-machine/myLib/src/iosMain/kotlin/ob/fus/client/utils/Dispatchers.kt:23:39)
        at 7   myLib                               0x0000000105d94164 _687364702d636c69656e74_knbridge14 + 180 (/Path-at-my-machine/myLib/src/iosMain/kotlin/ob/fus/client/utils/Dispatchers.kt:23:39)
        at 8   libdispatch.dylib                   0x00000001042dfdd4 _dispatch_call_block_and_release + 12
        at 9   libdispatch.dylib                   0x00000001042e0d48 _dispatch_client_callout + 8
        at 10  libdispatch.dylib                   0x00000001042eede6 _dispatch_main_queue_callback_4CF + 1500
        at 11  CoreFoundation                      0x00007fff23bd4049 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
        at 12  CoreFoundation                      0x00007fff23bceca9 __CFRunLoopRun + 2329
        at 13  CoreFoundation                      0x00007fff23bce066 CFRunLoopRunSpecific + 438
        at 14  GraphicsServices                    0x00007fff384c0bb0 GSEventRunModal + 65
        at 15  UIKitCore                           0x00007fff48092d4d UIApplicationMain + 1621
        at 16  HSDP Client                         0x0000000103327f5b main + 75 (Path-at-my-machine/myContainingApp/AppDelegate.swift:7:7)
        at 17  libdyld.dylib                       0x00007fff5227ec25 start + 1
Caused by: kotlin.native.concurrent.InvalidMutabilityException: mutation attempt of frozen io.hsdp.client.utils.$runAsync$lambda-1COROUTINE$200@36f9c78
        at 0   myLib                               0x00000001060dbec7 kfun:kotlin.Throwable.<init>(kotlin.String?)kotlin.Throwable + 87 (/Users/teamcity1/teamcity_work/4d622a065c544371/runtime/src/main/kotlin/kotlin/Throwable.kt:22:37)
        at 1   myLib                               0x00000001060cec95 kfun:kotlin.Exception.<init>(kotlin.String?)kotlin.Exception + 85 (/Users/teamcity1/teamcity_work/4d622a065c544371/runtime/src/main/kotlin/kotlin/Exceptions.kt:23:44)
        at 2   myLib                               0x00000001060ceeb5 kfun:kotlin.RuntimeException.<init>(kotlin.String?)kotlin.RuntimeException + 85 (/Users/teamcity1/teamcity_work/4d622a065c544371/runtime/src/main/kotlin/kotlin/Exceptions.kt:34:44)
        at 3   myLib                               0x0000000106123a45 kfun:kotlin.native.concurrent.InvalidMutabilityException.<init>(kotlin.String)kotlin.native.concurrent.InvalidMutabilityException + 85 (/Users/teamcity1/teamcity_work/4d622a065c544371/runtime/src/main/kotlin/kotlin/native/concurrent/Freezing.kt:22:60)
        at 4   myLib                               0x0000000106126bc8 ThrowInvalidMutabilityException + 680 (/Users/teamcity1/teamcity_work/4d622a065c544371/runtime/src/main/kotlin/kotlin/native/concurrent/Internal.kt:90:11)
        at 5   myLib                               0x0000000106518ea8 MutationCheck + 104
        at 6   myLib                               0x00000001061093f0 kfun:kotlin.coroutines.native.internal.ContinuationImpl.<set-intercepted>#internal + 96 (/Users/teamcity1/teamcity_work/4d622a065c544371/runtime/src/main/kotlin/kotlin/coroutines/ContinuationImpl.kt:98:13)
        at 7   myLib                               0x00000001061099fc kfun:kotlin.coroutines.native.internal.ContinuationImpl.releaseIntercepted() + 428 (/Users/teamcity1/teamcity_work/4d622a065c544371/runtime/src/main/kotlin/kotlin/coroutines/ContinuationImpl.kt:110:9)
        at 8   myLib                               0x0000000106108415 kfun:kotlin.coroutines.native.internal.BaseContinuationImpl.resumeWith(kotlin.Result<kotlin.Any?>) + 1253 (/Users/teamcity1/teamcity_work/4d622a065c544371/runtime/src/main/kotlin/kotlin/coroutines/ContinuationImpl.kt:36:17)
        at 9   myLib                               0x0000000106767073 kfun:kotlinx.coroutines.DispatchedTask.run() + 2579 (/Users/teamcity1/teamcity_work/4d622a065c544371/backend.native/build/stdlib/kotlin/coroutines/Continuation.kt:44:5)
        at 10  myLib                               0x0000000105d93f35 kfun:io.hsdp.client.utils.DispatchQueue.dispatch$lambda-0#internal + 85 (/Path-at-my-machine/myLib/src/iosMain/kotlin/ob/fus/client/utils/Dispatchers.kt:24:19)
        at 11  myLib                               0x0000000105d9401b kfun:io.hsdp.client.utils.DispatchQueue.$dispatch$lambda-0$FUNCTION_REFERENCE$492.invoke#internal + 59 (/Path-at-my-machine/myLib/src/iosMain/kotlin/ob/fus/client/utils/Dispatchers.kt:23:39)
        at 12  myLib                               0x0000000105d9407b kfun:io.hsdp.client.utils.DispatchQueue.$dispatch$lambda-0$FUNCTION_REFERENCE$492.$<bridge-UNN>invoke()#internal + 59 (/Path-at-my-machine/myLib/src/iosMain/kotlin/ob/fus/client/utils/Dispatchers.kt:23:39)
        at 13  myLib                               0x0000000105d94164 _687364702d636c69656e74_knbridge14 + 180 (/Path-at-my-machine/myLib/src/iosMain/kotlin/ob/fus/client/utils/Dispatchers.kt:23:39)
        at 14  libdispatch.dylib                   0x00000001042dfdd4 _dispatch_call_block_and_release + 12
        at 15  libdispatch.dylib                   0x00000001042e0d48 _dispatch_client_callout + 8
        at 16  libdispatch.dylib                   0x00000001042eede6 _dispatch_main_queue_callback_4CF + 1500
        at 17  CoreFoundation                      0x00007fff23bd4049 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
        at 18  CoreFoundation                      0x00007fff23bceca9 __CFRunLoopRun + 2329
        at 19  CoreFoundation                      0x00007fff23bce066 CFRunLoopRunSpecific + 438
        at 20  GraphicsServices                    0x00007fff384c0bb0 GSEventRunModal + 65
        at 21  UIKitCore                           0x00007fff48092d4d UIApplicationMain + 1621
        at 22  My Lib                              0x0000000103327f5b main + 75 (Path-at-my-machine/myContainingApp/AppDelegate.swift:7:7)
        at 23  libdyld.dylib                       0x00007fff5227ec25 start + 1

christophsturm

04/17/2020, 9:33 AM

whats the easiest way to use a master snapshot of ktor? can i build from source just for the jvm? if using jitpack for example

implementation("com.github.ktorio:ktor:master-SNAPSHOT")

i get unresolved symbols for example for jetty server

edenman

04/18/2020, 1:57 AM

Anybody seen

EOFException

from okhttp when using ktor websockets? receiving messages works great but I get this EOF anytime I try to send a message on the socket: https://github.com/ktorio/ktor/issues/1803

Stan Kocken

04/18/2020, 8:46 AM

I love what you do with Ktor ❤️ One small remark: within the doc (for example https://ktor.io/clients/index.html), it can be nice to have somewhere always visible the latest version, I’m always having a hard time to find the latest.

👍 9

waltermcq

04/19/2020, 1:34 AM

Question on ktor + exposed + coroutines

vishesh

04/19/2020, 7:09 PM

I am an experienced mobile application developer. Knows Kotlin, Swift, Dart and Java. I want to learn Server Side development suggest me a framework to start with. Thank You.

christophsturm

04/20/2020, 4:35 PM

if i send a post request like this:

<http://client.post|client.post><String>("....") {
                body = TextContent(stringBody, ContentType.Application.FormUrlEncoded)
            }

does it set a content type header? if I test the code with the MockEngine it has no content type header set.

Sam Garfinkel

04/21/2020, 7:56 PM

Can pipeline interceptors handle exceptions thrown further down in the pipeline? I’m trying to add a simple interceptor that retries a call (with a delay) if the call fails. I’d like this to supplement the existing timeout/validation features.

addamsson

04/22/2020, 11:54 AM

It is supposed to align, but I still get 415 form ktor. What am I doing wrong?

Antanas A.

04/23/2020, 7:26 AM

Hello, I've read in documentation that ktor supports http2 but it needs SSL/TLS which can be enabled with additional openssl netty's plugin/driver. But we're currently using HAProxy which already has a SSL support and your servers communicates in simple http mode. Is it possible in ktor to enable http2 (h2c) mode which would work without SSL/TLS encryption?

➕ 2

addamsson

04/24/2020, 11:19 AM

How do I perform

Bearer

authentication with #ktor ? I see that there is basic, jtw, etc, but there is no option for simply checking the bearer token.

Rachid

04/24/2020, 12:18 PM

Hi all, I'm playing around with ktor and now want to add application logging. I have a lot of

println

statements which I want to convert to INFO, DEBUG, etc When searching the internet I didn't find any good examples of how this could work in ktor. Only a minimal example of how to add logback for enabling logging in the frameworks used by ktor itself (like Netty). So know my question. Do you have any suggestions? And pointers/links to examples would be very helpful.

Orhan Tozan

04/24/2020, 12:20 PM

Of all the engines for JVM/Android for HTTP Client, which one is recommended?: Apache, CIO, Jetty, OkHttp, HttpUrlConnection?

ponzii

04/24/2020, 2:21 PM

I generated a new Ktor project using the IntelliJ plugin. The resulting build.gradle file has mainClassName = “io.ktor.server.netty.EngineMain” but when I build a fat Jar with Gradle I get java.lang.ClassNotFoundException: io.ktor.server.netty.EngineMain.

Dariusz Kuc

04/24/2020, 3:48 PM

hello! 👋 I’m hitting a pretty weird error from

HttpClient

and I am unsure whats causing it, given some result object when I run the following

lateinit var result: GraphQLResult<ExampleQuery.ExampleQueryResult>
runBlocking {
    val graphQLRequest = mapOf(
            "query" to EXAMPLE_QUERY,
            "operationName" to "ExampleQuery",
            "variables" to variables
    )
    result = <http://ktorClient.post|ktorClient.post>("<http://localhost:8080/graphql>") {
        accept(ContentType.Application.Json)
        contentType(ContentType.Application.Json)
        body = graphQLRequest
    }
    // works fine
    println("ktor: ${result.data}")

    val myClient = MyClient(ktorClient, "<http://localhost:8080/graphql>")
    result = myClient.executeOperation(EXAMPLE_QUERY, "ExampleQuery", variables)
    // blows up saying cannot cast linked hash map to my result object
    println("myClient: ${result.data}")
}

class MyClient(val client: HttpClient, val url: String) {
    suspend fun <T> executeOperation(query: String, operationName: String? = null, variables: Any? = null): GraphQLResult<T> {
        val graphQLRequest = mapOf(
                "query" to query,
                "operationName" to operationName,
                "variables" to variables
        )

        return <http://client.post|client.post>(url) {
            accept(ContentType.Application.Json)
            contentType(ContentType.Application.Json)
            body = graphQLRequest
        }
    }
}

any ideas why it would behave differently?

Anders Sveen

04/24/2020, 6:02 PM

Hi. 🙂 We are using KTor server (Netty engine), but seeing quite slow response times. Some of them are definitely our own fault, but some are usually fast then suddenly end up taking 20-30 seconds suddenly. The weird thing is that the front proxy closes the connection on a time out, but I can see from the logs that the call completes after the time out. My theory: The slow requests ends up blocking processing in KTor. I see the default for runningLimit is 10, does that mean max 10 parallel taks? So if 10 ends up slow, any new ones will be queued? Any thoughts on increasing the runningLimit number? Thanks. 🙂

Jitesh

04/26/2020, 2:38 PM

I am working on PoC using Ktor version 1.3.2 and have written simple POST API where I send 2 string params and return the same 2 strings. BUT, I am getting this error while using POST API

kotlinx/coroutines/io/ByteReadChannel

Any Idea what mistake am I doing?.

HTTP/1.1 500 Internal Server Error
Date: Sun, 26 Apr 2020 14:30:36 GMT
Content-Length: 37
Connection: keep-alive
Content-Type: text/plain; charset=UTF-8
Server: ktor-server-core/1.3.2 ktor-server-core/1.3.2

coder82

04/27/2020, 1:52 PM

Hi guys, KTOR doesn't seem to offer an option to do something specific if the netty responseWriteTimeoutSeconds or requestReadTimeoutSeconds trigger. Basically it's closing the connection without reporting any error to the browser. Is there a way to enforce a different closure or at least send an HTTP response with error code? You can reproduce this just by sleeping in request for more than the default time of those timeouts. I want to return 408 Request Timeout and not closing the connection abruptly, doesn't make sense, does it?

👍 2

rrva

04/28/2020, 5:47 AM

have trouble getting openapi or swagger to work. Can anyone point me to a recent example that works?

Anders Sveen

04/28/2020, 8:20 AM

Hey. I am doing a custom AuthenticationProvider and intercepting calls (both RequestAuthentication and CheckAuthentication) and returning av 401 when my custom checks fail. But it still reaches the endpoint code even though authentication fails. Is there some way to stop further processing? I have tried (a wild guess) to

return@intercept finish()

but it still continues processing.... Any idea?

addamsson

04/28/2020, 9:50 AM

Hi there! I'm trying to submit a form with the Ktor HttpClient but I get

RedirectResponseException: Unhandled redirect: <http://127.0.0.1:9000/login>. Status: 302 Found

This is nice because there is supposed to be a redirect but I can't figure out how to fix this. I'd like to check that the user was redirected to

after login.

crummy

04/28/2020, 11:28 PM

How do I register a customer serializer for a class using kotlinx serialization in Ktor?

Imran

04/29/2020, 11:42 AM

I am trying to get static files it is working with file extensions like

/static/xyz.json

but I want access it like

/static/xyz

. can anyone know how to do it?

dylan

04/29/2020, 3:06 PM

How do I set up the

HttpClient

with kotlinx.serializtion where every api endpoint has a custom vendor specific content-type? if I use the

accept()

function with multiple content-types they are also added to the accept header on the request which I don't want because we already specifiy that where I make the actual request. So api call

needs to send

Accept: application/vnd.a

and in return will get the

Content-Type: application/vnd.a

back in the response header and

sends

application/vnd.b

and is going to get

application/vnd.b

back. but I get NoTransformationFoundException: ByteBufferChannel => Serializable data class.

Title

dylan

04/29/2020, 3:06 PM

How do I set up the

HttpClient

with kotlinx.serializtion where every api endpoint has a custom vendor specific content-type? if I use the

accept()

function with multiple content-types they are also added to the accept header on the request which I don't want because we already specifiy that where I make the actual request. So api call

needs to send

Accept: application/vnd.a

and in return will get the

Content-Type: application/vnd.a

back in the response header and

sends

application/vnd.b

and is going to get

application/vnd.b

back. but I get NoTransformationFoundException: ByteBufferChannel => Serializable data class.

Ayman Izzeldin

04/29/2020, 6:40 PM

if I understand the question correctly, you can create a copy of the http client, and reconfigure it (this new client will reuse the same underlying engine.) Something along the lines of:

val apiAClient = myHttpClient.config {
    Json { acceptContentTypes = acceptContentTypes + ContentType.parse("application/vnd.a") }
}

dylan

04/29/2020, 9:13 PM

Seems a bit boilerplaty to copy an instance of the httpclient for every separate api call we make

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