Routing

Learn URL routes with routing.

What is routing?

Routing directs incoming HTTP requests to handler functions by URL path. In Ktor it is declared with the routing block.

Example: routing { get("/users") { call.respondText("users") } }. Here a GET request to /users is answered with call.respondText. Each route binds to an HTTP method: get, post, put, delete. Path parameters use the {id} syntax. The routing block lives inside the Application module.

HTTP methods

In the routing block each route binds to an HTTP method. get reads, post creates, put updates and delete removes.

Example: post("/users") { call.respondText("Created") }. To return a response use call.respondText, call.respond or call.respondBytes. To read the request body use call.receive<T>(). Path parameters are read with call.parameters["id"]. Routing is the basis of REST API design.

Exercise Add a route with routing

Define fun Application.module(). Inside it, open a routing { get("/users") { } } block. Also print println("Route added") inside fun main().

Show example solution

fun Application.module() {
    routing {
        get("/users") {
        }
    }
}

fun main() {
    println("Route added")
}

Test yourself

Complete the routing block

fun Application.module() {
    ____ {
        get("/users") { }
    }
}

Show answer

fun Application.module() {
    routing {
        get("/users") { }
    }
}

Match HTTP methods

get

Read
post

Create
put

Update
delete

Delete
Which is used to read a path parameter?
- call.respond
- call.respondText
- call.receive
- call.parameters
Show answer

call.parameters — call.parameters reads a path parameter.

Next lesson: Application

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies