JTE

Ktor allows you to use JTE templates as views within your application by installing the Jte plugin.

Add dependencies

To use Jte, you need to include the ktor-server-jte artifact in the build script:

implementation("io.ktor:ktor-server-jte:$ktor_version")

implementation "io.ktor:ktor-server-jte:$ktor_version"

        
                    <dependency>
                        <groupId>io.ktor</groupId>
                        <artifactId>ktor-server-jte-jvm</artifactId>
                        <version>${ktor_version}</version>
                    </dependency>
                    
        

Install Jte

To install the Jte plugin to the application, pass it to the install function in the specified module. The code snippets below show how to install Jte...

... inside the embeddedServer function call.
... inside the explicitly defined module, which is an extension function of the Application class.

                    import io.ktor.server.application.*
                    import io.ktor.server.jte.*
                    // ...
                    fun main() {
                        embeddedServer(Netty, port = 8080) {
                            install(Jte)
                            // ...
                        }.start(wait = true)
                    }
                

                    import io.ktor.server.application.*
                    import io.ktor.server.jte.*
                    // ...
                    fun Application.module() {
                        install(Jte)
                        // ...
                    }
                

Inside the install block, you can configure how to load JTE templates.

Configure Jte

Configure template loading

To load JTE templates, you need to:

Create a CodeResolver used to resolve template code. For example, you can configure DirectoryCodeResolver to load templates from a given directory or ResourceCodeResolver to load templates from application resources.
Use the templateEngine property to specify a template engine, which uses a created CodeResolver to transfer templates into native Java/Kotlin code.

For instance, the code snippet below enables Ktor to look up JTE templates in the templates directory:

import gg.jte.TemplateEngine
import gg.jte.resolve.DirectoryCodeResolver
import io.ktor.server.application.*
import io.ktor.server.jte.*
import java.nio.file.Path

fun Application.module() {
    install(Jte) {
        val resolver = DirectoryCodeResolver(Path.of("templates"))
        templateEngine = TemplateEngine.create(resolver, gg.jte.ContentType.Html)
    }
}

Send a template in response

Suppose you have the index.kte template in the templates directory:

@param id: Int
@param name: String
<html>
    <body>
        <h1>Hello, ${name}!</h1>
    </body>
</html>

To use the template for the specified route, pass JteContent to the call.respond method in the following way:

        get("/index") {
            val params = mapOf("id" to 1, "name" to "John")
            call.respond(JteContent("index.kte", params))
        }

Last modified: 21 September 2022