I am trying to learn to use ktor and I'm trying to display the text "Hello Ktor" at the root path but all I keep getting is this site can't be reached.
This is my code:
import io.ktor.application.*
import io.ktor.http.ContentType
import io.ktor.response.respondText
import io.ktor.routing.get
import io.ktor.routing.routing
fun main(args: Array<String>): Unit = io.ktor.server.netty.EngineMain.main(args)
private val userData = "{\"users\": [\"Timi\", \"Tomi\", \"Temi\"]}"
#Suppress("unused") // Referenced in application.conf
#kotlin.jvm.JvmOverloads
fun Application.module(testing: Boolean = false) {
routing {
get("/") {
call.respondText("Hello Ktor", ContentType.Text.Plain)
}
}
}
What am I doing wrong?
Your code is fine.
I think you just need to access it correctly from browser.
Try
127.0.0.1:8080
or
localhost:8080
or simply follow nice tutorial from official website.
Are you trying to run without a main?
Did you follow this guide? https://ktor.io/quickstart/quickstart/gradle.html#intellij-extract-out-configuration-data
If you want to start from main, use embeddedServer. Otherwise you have to set the mainClassName.
Related
Hi im trying to write ktor testcases with koin dependency injection and in the tutorial im watching the person uses withTestApplication(moduleFunction = {install(Routing)}) Though withTestApplication() is deprecated and so the moduleFunction part does not work with the new testApplication() setup what should i do instead is my question? this is the tutorial im watching Tutorial
i have also checked
https://ktor.io/docs/migrating-2.html#testing-api
and
https://insert-koin.io/docs/reference/koin-test/testing
To configure a module using testApplication use the application method:
import io.ktor.server.application.*
import io.ktor.server.routing.*
import io.ktor.server.testing.*
import kotlin.test.Test
class KtorTest {
#Test
fun test() = testApplication {
application {
install(Routing)
}
}
}
Okay so this may sound like a stupid question, but I really need to know, is there a way to create multiple domains programatically with Ktor. For example, let's say that I have a domain: example.com
Now I need the logic on my backend server to create a new subdomain for each user that register on my website. For example, when John register, I want to immediately be able to create a new subdomain: john.example.com . Now I'm not sure what and how this can be achieved, that's why I'm asking here for some directions?
And if that's too complex, then is there a way to create multiple endpoints dynamically from the code, after each and every user registration on my website, like: example.com/John ?
Is there any good resource that I can read about that?
On the Ktor side, you can add routes dynamically after the server startup and use the host route builder to match the requested host. Additionally, you need to add DNS entries programmatically as #Stephen Jennings said. Here's an example where after 5 seconds the route for the host john.example.com is added. You can test it locally with the entry 127.0.0.1 john.example.com in the /etc/hosts file.
import io.ktor.application.*
import io.ktor.http.*
import io.ktor.response.*
import io.ktor.routing.*
import io.ktor.server.engine.*
import io.ktor.server.netty.*
import kotlinx.coroutines.*
fun main() {
val server = embeddedServer(Netty, port = 4444) {
routing {
get("/example") {
call.respondText { "example" }
}
}
}
server.start(wait = false)
CoroutineScope(Dispatchers.IO).launch {
delay(5000)
val routing = server.application.feature(Routing)
routing.addRoutesForHost("john.example.com")
}
}
fun Route.addRoutesForHost(host: String) {
host(host) {
get("/hello") {
call.respondText { "Hello ${call.request.headers[HttpHeaders.Host]}" }
}
}
}
I want to make a simple http server using ktor. However, when I enter the site (127.0.0.1:8080 or 0.0.0.0:8080), it just isn't there. It doesn't print and doesn't respond.
However if I use NanoHttpd instead of ktor, everything works fine. What is my issue?
import io.ktor.application.call
import io.ktor.http.ContentType
import io.ktor.response.respondText
import io.ktor.routing.get
import io.ktor.routing.routing
import io.ktor.server.engine.embeddedServer
import io.ktor.server.netty.Netty
fun main() {
val server = embeddedServer(Netty, port = 8080) {
routing {
get("/") {
println("TEST")
call.respondText("Hello World!", ContentType.Text.Plain)
}
}
}
server.start(wait = true)
}
The output is just:
[main] INFO ktor.application - No ktor.deployment.watch patterns specified, automatic reload is not active
[main] INFO ktor.application - Responding at http://0.0.0.0:8080
It could be one of the following things:
The application code
The run configuration
I am leaning towards there being a problem with the run configuration rather than the application code.
Application code
Even though I think your issue is with the run configuration, in case that it isn't, I'm providing sample code here.
When I use the IntelliJ Ktor plugin, the Ktor app is bootstrapped as follows:
Application.kt
package com.example
import io.ktor.application.*
import io.ktor.http.*
import io.ktor.response.*
import io.ktor.routing.*
fun main(args: Array<String>): Unit = io.ktor.server.netty.EngineMain.main(args)
#kotlin.jvm.JvmOverloads
#Suppress("unused") // Referenced in application.conf
fun Application.module(testing: Boolean = false) {
routing {
get("/") {
call.respondText("Hello, world!", ContentType.Text.Plain)
}
}
}
application.conf
ktor {
deployment {
port = 8080
port = ${?PORT}
}
application {
modules = [ com.example.ApplicationKt.module ]
}
}
I've provided an example Ktor code base here: https://gitlab.com/tinacious/ktor-example
Run configuration
It could be your run configuration in IntelliJ. It needs to be set up as a Kotlin script (and not an Application). When it's set up as an Application, I get the same error you do. Here is how to set up the run configuration I have, allowing me to run the server in IntelliJ:
Add a configuration
Choose Kotlin script from the Templates section. Do not choose Application.
Near the bottom where it says "Use classpath of module" choose your application.main.
Near the top where it says "Main class" you should be able to choose your main application. I found this only showed up after I chose the classpath of the module.
Here are the relevant sections in the configuration:
Here is what I describe in step 4, i.e. I can choose my main class after the class path is added:
The run symbol should be a Kotlin logo:
I would recommend installing the IntelliJ Ktor plugin for bootstrapping your project. It uses Gradle and bootstraps everything so when you run ./gradlew run, you are running it properly and can access it without the manual build configuration step.
I am trying to use micronaut from Kotlin. I have this:
package me.test
import io.micronaut.http.MediaType
import io.micronaut.http.annotation.Controller
import io.micronaut.http.annotation.Get
import io.micronaut.http.annotation.Produces
#Controller("/hello")
class Controller() {
#Get("/")
#Produces(MediaType.TEXT_PLAIN)
fun ping(): String {
return "hello world"
}
}
package me.test
import io.micronaut.runtime.Micronaut
object Application {
#JvmStatic
fun main(args: Array<String>) {
Micronaut.build()
.packages("me.test")
.mainClass(Application.javaClass)
.start()
}
}
I wrote the following controller test:
package me.test
import io.micronaut.http.client.RxHttpClient
import io.micronaut.http.client.annotation.Client
import io.micronaut.test.annotation.MicronautTest
import org.junit.jupiter.api.Test
import javax.inject.Inject
#MicronautTest(application = Application::class)
class ControllerTest {
#Inject
#field:Client("/")
private lateinit var client: RxHttpClient
#Test
fun `should server ping with a pong`() {
val result = client.toBlocking().retrieve("/hello")
println(result)
}
}
but the test fails with a HttpClientResponseException: Page Not Found.
I have debugged this and from what I can tell, during the test, in DefaultBeanContext.getBeanDefinitions it doesn't find any beans for the #Controller qualifier. When I start the application using my Application class, I can see that it finds the Controller and makes the route available.
This is pretty much the Hello World for Micronaut, I am not sure what's going wrong here.
I think this is purely IDE related. I have Intellij set up to use Annotation Processors, to delegate builds to Gradle and to use the Gradle Test Runner. However, you also need to delete any existing test configurations and then the problem goes away.
I'm learning how to use Dagger 2 and MVP architeture.
But I'm stuck in this error now:
Unresolved reference: DaggerHelloComponent
Look, this is my module:
#Module
class HelloModule {
lateinit var activityDagger: HelloActivityDagger
constructor(activityDagger: HelloActivityDagger) {
this.activityDagger = activityDagger
}
#Provides
fun providesHelloPresenter(): HelloActivityPresenterDagger = HelloActivityPresenterDagger(activityDagger)
}
and my component:
#Component(modules = [HelloModule::class])
interface HelloComponent {
fun inject(activityDagger: HelloActivityDagger)
}
So when I try to builder this component like this DaggerHelloComponent.create().inject(this) in my HelloActivityDagger shows me the error above.
Anyone know what I am doing wrong?
Cause I can see whats wrong in this code.
Oh, I already have followed this kapt things from this question Unresolved reference DaggerApplicationComponent and nothing happens
EDIT
To be more readable I`ve uploaded my project to Git. https://github.com/luangs7/DaggerMvpExample
Putting this code in the MyApplication class works for me to create the module starting off from your GitHub project - after the first failed build, kapt generates the DaggerHelloComponent class, and I can import it.
import android.app.Application
import br.com.squarebits.mvpexample.DaggerMvp.componentes.DaggerHelloComponent
import br.com.squarebits.mvpexample.DaggerMvp.componentes.HelloComponent
import br.com.squarebits.mvpexample.DaggerMvp.modules.HelloModule
class MyApplication : Application() {
val component: HelloComponent by lazy {
DaggerHelloComponent.builder()
.helloModule(HelloModule(HelloActivityDagger()))
.build()
}
}
If this is not happening at all, you should try the usual debugging steps of restarting Studio with File -> Invalidate Caches / Restart, cleaning and rebuilding your project, etc. Perhaps try pulling the GitHub repo to a new location and see if that builds for you - the code isn't the problem.