Thymeleaf

Ktor allows you to use Thymeleaf templates as views within your application by installing the Thymeleaf feature.

Add Dependencies

To enable Thymeleaf support, you need to include the ktor-thymeleaf artifact in the build script:

Gradle (Groovy)

Gradle (Kotlin)

Maven

1. implementation "io.ktor:ktor-thymeleaf:$ktor_version"

Install Thymeleaf

To install the Thymeleaf feature, pass it to the install function in the application initialization code. This can be the main function …

1. import io.ktor.features.*
2. // ...
3. fun Application.main() {
4. install(Thymeleaf)
5. // ...
6. }

… or a specified module:

1. import io.ktor.features.*
2. // ...
3. fun Application.module() {
4. install(Thymeleaf)
5. // ...
6. }

Configure Thymeleaf

Configure Template Loading

Inside the install block, you can configure the ClassLoaderTemplateResolver. For example, the code snippet below enables Ktor to look up *.html templates in the templates package relative to the current classpath:

1. import io.ktor.thymeleaf.*

3. install(Thymeleaf) {
4. setTemplateResolver(ClassLoaderTemplateResolver().apply {
5. prefix = "templates/"
6. suffix = ".html"
7. characterEncoding = "utf-8"
8. })
9. }

Send a Template in Response

Imagine you have the index.html template in resources/templates:

1. <html xmlns:th="http://www.thymeleaf.org">
2. <body>
3. <h1 th:text="'Hello, ' + ${user.name}"></h1>
4. </body>
5. </html>

A data model for a user looks as follows:

1. data class User(val id: Int, val name: String)

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

1. get("/index") {
2. val sampleUser = User(1, "John")
3. call.respond(ThymeleafContent("index", mapOf("user" to sampleUser)))
4. }