kotlinlang #spring

Hi, I have a Spring MVC API written with Kotlin. I would like to begin using some coroutines inside for some basic usecases. For example : on an API call, I want to fire&forget a coroutine that will do some background job. I don’t care if the job fail & I don’t need to cancel the job. What is the best CoroutineScope to use for launching the coroutine ? Is GlobalScope OK for this usecase or should i use a custom CoroutineScope ? If so, when should I create it ? thx

Dariusz Kuc

08/25/2020, 6:08 PM

hello! 👋 is there a preferred way of setting up Spring WebClient timeouts? e.g. I could wrap it in

withTimeout

coroutine

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withTimeout(1000) {
  <http://client.post|client.post>().bodyValue(myValue).awaitExchange().awaitBody<String>()
}

or I could apply the timeout on the

Mono

from the above, e.g.

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<http://client.post|client.post>()
    .bodyValue(myValue)
    .awaitExchange()
    .bodyToMono(String::class.java)
    .timeout(Duration.ofMillis(1000)
    .awaitSingle()

I’m wondering whether #1 above might have some unintended side effects

Ayodele

09/01/2020, 10:28 AM

and its a valid phone number because its the same number i used in the application.kt file

corneil

09/02/2020, 6:51 AM

What is the format of your number?

AlexJuca

09/02/2020, 3:38 PM

Idiomatic kotlin preconditions for spring boot Restful API's I would love your feedback on this. If you could contribute any ideas by creating issues and providing constructive feedback, it would be immensely helpful. https://github.com/nextbss/requirekt

K 1

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✔️ 1

Gopal Kalyanaraman

09/03/2020, 1:52 PM

Hi all .. pls share any examples of a working complex actor with spring services.

🤷‍♂️ 1

google 3

Marcel Champagne

09/04/2020, 11:16 PM

Is it safe to use OAuth2AuthenticatedPrincipal name as a unique ID to allow access to user resources? If the application supports multiple oAuth providers (e.g. Google, GitHub) could there be a conflict of IDs?

Marcel Champagne

09/04/2020, 11:17 PM

If not, is the common approach to use a registration ID plus the Principal name? And if so does that mean the principal name is always unique across users under a single oAuth provider?

nathan

09/06/2020, 6:54 PM

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@Entity
@Table(name="comment")
class Comment (
        @Id @GeneratedValue (strategy = GenerationType.AUTO) var id: Long,
        var body : String,
        var video_link: String,
        var image_link: String,
)

sdeleuze

09/15/2020, 7:02 PM

https://kotlinlang.slack.com/archives/C0BJ0GTE2/p1600196516100300

🙂 1

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alwyn

09/17/2020, 7:14 PM

This is more a language question, but it is influenced by the Spring flavour. I have a private field set by Spring constructor injection. Is there any way I can add a get() for that private field?

nathan

09/17/2020, 8:11 PM

So if im planning to implement a DTO, I would need a Controller, DtoToEntityConverter, DTO, entity, and repostiory?

Ayodele

09/18/2020, 8:21 AM

Please help

cueball

09/25/2020, 4:24 AM

Hi guys, I’m struggling with a piece of code while trying to use coroutines. I’m calling Spring’s

reactive.function.client

method

awaitBody()

from a Generic class and am running into error:

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Kotlin: Cannot use 'Response' as reified type parameter. Use a class instead.

---

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class ReactiveWebClient<Request: Any, Response: Any> {

    suspend fun post(uri: URI, request: Request, headers: (HttpHeaders) -> Unit): Response {
        return <http://webClient.post|webClient.post>()
            .uri(uri)
            .body(BodyInserters.fromValue(request))
            .headers(headers)
            .retrieve()
            .awaitBody()  // error on this line
    }
}

Signature of `awaitBody`:

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public suspend inline fun <reified T : kotlin.Any> org.springframework.web.reactive.function.client.WebClient.ResponseSpec.awaitBody(): T { /* compiled code */ }

Can someone please help? I’m not so well versed with Kotlin’s type parameters. Slack Conversation

Esa

10/08/2020, 11:07 AM

Hi guys, I'm looking to start monitoring network wait times across my application. I currently use spring-aop to have aspect oriented logging, but I have no way to connect a request received in the RestController with a function call in the data access layer unless I pass a RequestId as a parameter all the way to the dao. How does one typically handle this? Java / C# has ThreadLocal-stuff you can use to carry that type of information, I'm just not sure how to go about it in kotlin. Any ideas welcome.

Esa

10/08/2020, 11:11 AM

I concidered generating an ID in the restcontroller and passing that to every method, but I dropped that idea pretty fast

jbnizet

10/08/2020, 11:16 AM

Your app runs on the JVM, and Kotlin is interoperable with Java. So you can use a ThreadLocal.

Esa

10/08/2020, 11:17 AM

Okay. So the fact I use coroutines extensively in this app will not interfere with that?

jbnizet

10/08/2020, 11:19 AM

Yes it will, most probably. I’m not competent enough to answer if you use coroutines. Sorry.

nathan

10/13/2020, 4:18 AM

cuz mutable list could be read and updated

avolkmann

10/13/2020, 3:55 PM

Just tried setting

useIR = true

and suddenly default constructors were not generated for entities anymore. Has anyone encountered this? Found: https://youtrack.jetbrains.com/issue/KT-41265

sdeleuze

10/15/2020, 9:32 AM

https://twitter.com/sdeleuze/status/1316672484415098881

sdeleuze

10/15/2020, 9:32 AM

See you there this afternoon if you are interested 😉

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wakingrufus

10/15/2020, 3:03 PM

great presentation!