Migrating from 2.2.x to 3.0.x

This guide provides instructions on how to migrate your Ktor application from the 2.2.x version to 3.0.x.

Ktor Server

Locations plugin has been removed

The Locations plugin for the Ktor server has been removed. To create type-safe routing, use the Resources plugin instead. This requires the following changes:

Replace the io.ktor:ktor-server-locations artifact with io.ktor:ktor-server-resources.
The Resources plugin depends on the Kotlin serialization plugin. To add the serialization plugin, see the kotlinx.serialization setup.
Update the plugin import from io.ktor.server.locations.* to io.ktor.server.resources.*.
Additionally, import the Resource module from io.ktor.resources.

The following example shows how to implement these changes:

import io.ktor.server.locations.*

@Location("/articles")
class article(val value: Int)

fun Application.module() {
    install(Locations)
    routing {
        get<article> {
            // Get all articles ...
            call.respondText("List of articles")
        }
    }
}

import io.ktor.resources.Resource
import io.ktor.server.resources.*

@Resource("/articles")
class Articles(val value: Int)

fun Application.module() {
    install(Resources)
    routing {
        get<Articles> {
            // Get all articles ...
            call.respondText("List of articles")
        }
    }
}

For more information on working with Resources, refer to Type-safe routing.

Last modified: 11 October 2023