Hi everyone, could you please recommend a reactivate flow connector to Redis based on kotlin coroutines? Thanks

Guys I have moved my backend to KMP, it is uses ktor with SQLDeleight When I run it on local with

./gradlew :backend:run

everything works as expected I can reach it by

<http://127.0.0.1:8080/endpoint>

it reposes. I have created a fat jar and run in my server but I can not get response when i

<http://IP_ADRESS:8080/endpoint>

the main is below

// Configs
private const val PORT = 8080
private const val HOST = "127.0.0.1"

fun main() {
....
    embeddedServer(
        Netty,
        port = PORT,
        host = HOST
    ) {

        routing {
         ....
        }
    }.start(wait = true)
}

What can be the reason, I have allowed my port also

Is this any engine for this in kotlin ?

what do you use for background work queueing. Something like celery in python?

Hi All! Does anyone have experience running a kotlin service in Docker?

Hi all - is anyone using gradle with kotlin with docker with buildkite? I'm trying to get my head around setting up a sensible pipeline.

Which is better to choose Ktor http2 or WebSockets?

Hi all, is anyone have worked on standardisation of rest API specifications, like - path conventions, request body conventions, variables, etc. I got one tool zally getting multiple issues while building the project. Any leads, suggestions will be highly appreciated as we have got to around 175+ micro-services for standardisation. #kotlin, #Groovy, #gradlew #jersey #rest

Hello friends! I want to learn ktor, and for me reading the docs is not enough. I want to learn it by re-implementing an existing API, bigger than hello world but still of a manageable size. In the past I reimplemented httpbin.org - and contributed that ktor sample - and I'm looking for something similar. Any idea?

While looking for best user input sanitizing practices, I found that Ktor has a

String.escapeIfNeeded

method, is it enough to protect my database from injection and other possible attacks? I also found apache

commons-text

library that has

StringEscapeUtils

but it seems a bit less practical since there’s an escape method for java, one for ecmascript, etc…

Hi! I created a backend based on the Clean Architecture principles. Feedback would be very much appreciated! The application is separated into three modules: Domain, Usecases and Adapters • Domain module contains all entities, it's validation and repository interfaces • Usecases module performs actions on the domain entities and repositories and does authorization The domain and usecase modules do not have any external dependencies. • Adapter layer: each adapter is implemented as a standalone module, lowering dependence on specific frameworks and libraries and making them interchangable. The server module consumes all adapters (e.g. databases, (graphql) endpoints, authentication logic) GraphQL endpoints are auto-generated from the Usecases Used technologies: Ktor, JWT, Exposed, Flyway, KGraphQL/GraphQL generated endpoints. https://github.com/ESchouten/CleanArchitecture

Hello everyone, been developing a restapi with ktor and ran into a problem with kors, on postman works fine but when i try doing it from website with fetch and javascript it runs into an error saying that "cannot convert from text/plain" even when im using fetch with content type application/json and when i have gson on my ktor server

install(CORS) {
    method(HttpMethod.Get)
    method(<http://HttpMethod.Post|HttpMethod.Post>)
    method(HttpMethod.Put)
    method(HttpMethod.Delete)
    method(HttpMethod.Head)
    method(HttpMethod.Options)
    header(HttpHeaders.AccessControlAllowHeaders)
    header(HttpHeaders.AccessControlAllowOrigin)
    header(HttpHeaders.Authorization)
    allowCredentials = true
    allowSameOrigin = true
    anyHost()
}

this is my cors and when i add this line works (obvs cause it accepts text/plain) but dont understand whats happening

allowNonSimpleContentTypes = true

I have a question that has more to do with microservices than with Kotlin but I think here are the experts. I have my Profile/User - Service (A): there profiles are created and root information is stored e.g.: .

User: {name: "potter", street: "hogwards-street", type: "cleaner"}

I publish these to my message broker and consumed it in an another service (B). Now the service (B) only needs

{name: String, type: String}

. Should I still share the full model of

User

as interface between the services or are these other types of

User

models?

Hello guys. I have been trying to build a Docker image for my ktor server application and i keep on getting an error. This is the Docker and the .yml file:

FROM openjdk:13 AS builder
RUN java --version
RUN mkdir /application
WORKDIR /application
COPY ./ ./
RUN ./gradlew clean build
RUN ls -al build/libs/

...

version: "3"
services:
  myapp:
    build: .

And this is the error i keep getting:

ERROR [6/7] RUN ./gradlew clean build                                                                                                                     1.9s
------
 > [6/7] RUN ./gradlew clean build:
#10 1.339 /bin/sh: ./gradlew: No such file or directory
------
executor failed running [/bin/sh -c ./gradlew clean build]: exit code: 127
ERROR: Service 'myapp' failed to build : Build failed

After trying lots of solutions, i decided to use another approach:

FROM openjdk:8-jre-alpine
ENV APPLICATION_USER ktor
RUN adduser -D -g '' $APPLICATION_USER
RUN mkdir /app
RUN chown -R $APPLICATION_USER /app
USER $APPLICATION_USER
COPY ./build/libs/app.jar /app/app.jar
WORKDIR /app
CMD ["java","-server","-XX:+UnlockExperimentalVMOptions","-XX:+UseCGroupMemoryLimitForHeap","-XX:InitialRAMFraction=2","-XX:MinRAMFraction=2","-XX:MaxRAMFraction=2","-XX:+UseG1GC","-XX:MaxGCPauseMillis=100","-XX:+UseStringDeduplication","-jar","app.jar"]

And i also got a similar error:

ERROR [5/6] COPY ./build/libs/app.jar /app/app.jar                                                                                                        0.0s
------
 > [5/6] COPY ./build/libs/app.jar /app/app.jar:
------
failed to compute cache key: "/build/libs/app.jar" not found: not found

Working on automatic migrations in Ktorm: https://github.com/kotlin-orm/ktorm-migration

Hi. I'm trying to build a server that handles udp communication using raw sockets. However, when I open multiple sockets, the communication seems to be delayed by about 5000ms. Is this because ktor is not able to handle multiple sockets async or something?

Hi, I have a question regarding Spring graphQL data/error management. I have a use case where I want to return several results, including the error ones, as a Union. something like this:

extend type Mutation {
userCreate(): UserCreatePayload
}
union UserCreatePayload = UserCreated | UserAlreadyExists

I have a MutationsResolver that handles the

userCreate

mutation by calling a

UserService

that is transactional. When trying to create a user, if the user already exists, I'm throwing a

UserAlreadyExist

Exception that is handled in the mutation resolver with a try/catch block and then mapped to the UserAlreadyExists type in graphql. The problem is that as the UserService is transactional, whenever I throw the exception, the transaction is marked a rollbackOnly by spring (which is good) and then the graphql flow goes through the DefaultGraphQLErrorHandler that finally return an error to the end user. I would like to have the exactly same behavior except for the graphql error handler returning a GraphqlError. Instead I want to return the

UserAlreadyExists

type I defined in the graphql schema. Is there anyway to do so? (I do not want to use sealed classes instead of exceptions in the service as the code gets dirty) Thanks!

Hi, I have a question about Ktor, maybe anyone solved this already: Is there a way to get/log actual amount of received/sent bytes for the HTTP request?

Hi All, I'm trying to run a Ktor server on android but cannot get the static webpage to display on the browser. I've added an assets folder and place the website as a subfolder in it, The request is recognized but the path I give in the response always seems to be wrong. Any ideas what I'm doing wrong?

Is there any overview of different server-side kotlin frameworks (e.g. Ktor, Spring Kotlin, http4k) with comparisons?

I'm currently prototyping a Kotlin/JVM server app that will use Firestore as the backend data storage. I noticed that com.google.firebase:firebase-admin:8.0.1 seems to be lacking in documentation and Kotlin extensions for Firestore (Realtime DB seems to have a better experience, but doesn't fit the data structure I need as well). Does anyone know of a better Firestore library for Kotlin/JVM (specifically for a server application)?

hello everyone! i am building a ktor backend at the moment and use Locations for the routing. the documentation states

If you provide additional class properties that are not part of the path of the @Location, those parameters will be obtained from the GET's query string or POST parameters

While this seems to work fine for non-optional query parameters, i can't find any documentation on how to make the query parameters optional. out of intuition i tried to make location data class parameters nullable but this does not seem to lead to expected behavior. I wanted to have these routes:

/user?page=1&count=10
/user/{id}

this was done with following code:

@Location("/user")
data class UserRoute(val page: Int?, val count: Int?) {

    @Location("/{id}")
    data class ById(val parent: UserRoute, val id: String)

}

but now performing a GET on

/user

results in a 404 if i don't provide the query parameters and works perfectly for

/user?page=1&count=10

is there any documentation i missed or maybe someone can give me a quick kick into the right direction? thank you in advance!

Hey folks! 👋 I'm a product manager for the :kotlin:Kotlin server-side. I'm looking for people to talk to about different aspects of their development experience from time to time. And today, I'm looking for folks who share code between their backend, web, and mobile apps. If you have such cases in your practice, please put ➕, and I will contact you. I appreciate your willingness and time, and after the interview, you will be able to choose your prize: an Amazon gift card or a one-year All-product pack subscription.🏆

hi, if I cancel a coroutine

Job

is there a way to find out where it was stuck? I can pass a

CancellationException

in, but what I really want is a traceback for where it was when it got cancelled.

Hi, please is there a way to automatically generate swagger ui in ktor?

I have a Kotlin/Spring Boot application in which I am doing a simple string comparison against a string literal within a list filter. Initially I used

===

, and all of my unit tests passed. However, once deployed, the filter function did not work as expected. I wrote an simple JVM app to see if it was an issue with JVM specifically, but in that case

"str" === "str"

resolved to true, which is not the behavior I was seeing in my Spring Boot app. Any ideas why I'd be seeing this discrepancy in the Spring Boot app?

Hello everyone, is it possible to get all the keys of nested Json using Kotlin without using actual class, similar to JavaScript?

How can I dynamically set CORS in ktor.io? Unfortunatelly

call.request.origin.host

returns

localhost

and after some reconfiguration of nginx it returns

<http://backend.domain.com|backend.domain.com>

instead of

<http://frontend.domain.com|frontend.domain.com>

. Setting up CORS for all endpoints with

host("<http://frontend.domain.com|frontend.domain.com>")

works properly, allows only frontend domain, and blocks all other

Hi guys, I've read that kafka consumers are not thread-safe. does this mean that I can't(or shouldn't) run consumers in asynchronous servers? sry if this is a dumb question. yep it was 😅 i guess multithreading is not allowed while async is different