Ktor 2.0.3 Help

Default headers

The DefaultHeaders plugin adds the standard Server and Date headers into each response. Moreover, you can provide additional default headers and override the Server header.

Add dependencies

To use DefaultHeaders, you need to include the ktor-server-default-headers artifact in the build script:

implementation("io.ktor:ktor-server-default-headers:$ktor_version")
implementation "io.ktor:ktor-server-default-headers:$ktor_version"
<dependency> <groupId>io.ktor</groupId> <artifactId>ktor-server-default-headers-jvm</artifactId> <version>${ktor_version}</version> </dependency>

Install DefaultHeaders

To install the DefaultHeaders plugin, pass it to the install function in the application initialization code. Depending on the way used to create a server, this can be the embeddedServer function call ...

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

... or a specified module.

import io.ktor.server.application.* import io.ktor.server.plugins.defaultheaders.* // ... fun Application.module() { install(DefaultHeaders) // ... }

The DefaultHeaders plugin adds the Server and Date headers into each response. If necessary, you can override the Server, as described in Override headers.

Add additional headers

To customize a list of default headers, pass a desired header to install by using the header(name, value) function. The name parameter accepts an HttpHeaders value, for example:

install(DefaultHeaders) { header(HttpHeaders.ETag, "7c876b7e") }

To add a custom header, pass its name as a string value:

install(DefaultHeaders) { header("Custom-Header", "Some value") }

Override headers

To override the Server header, use a corresponding HttpHeaders value:

install(DefaultHeaders) { header(HttpHeaders.Server, "Custom") }

Note that the Date header is cached due to performance reasons and cannot be overridden by using DefaultHeaders.

Last modified: 28 June 2022