Using Freemarker Templates

Estimated reading time: 1 minute

Ktor includes support for FreeMarker templates through the FreeMarker feature. Initialize the FreeMarker feature with a TemplateLoader:

    install(FreeMarker) {
        templateLoader = ClassTemplateLoader(TheApp::class.java.classLoader, "templates")
    }

This TemplateLoader sets up FreeMarker to look for the template files on the classpath in the “templates” package, relative to the current class path. A basic template looks like this:

This feature is defined in the class io.ktor.freemarker.FreeMarker in the artifact io.ktor:ktor-freemarker:$ktor_version.

dependencies {
    compile "io.ktor:ktor-freemarker:$ktor_version"
}

dependencies {
    compile("io.ktor:ktor-freemarker:$ktor_version")
}

<project>
    ...
    <dependencies>
        <dependency>
            <groupId>io.ktor</groupId>
            <artifactId>ktor-freemarker</artifactId>
            <version>${ktor.version}</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>
</project>

<html>
<h2>Hello ${user.name}!</h2>

Your email address is ${user.email}
</html>

With that template in resources/templates it is accessible elsewhere in the the application using the call.respond() method:

    get("/{...}") {
        val user = User("user name", "user@example.com")
        call.respond(FreeMarkerContent("index.ftl", mapOf("user" to user), "e"))
    }