Cookbooks
Kotlin
Chapter 11. HTML and the Web
Sending an HTTP request with basic authentication

Kotlin:
Sending an HTTP request with basic authentication

How to:

Kotlin handles HTTP requests with libraries like ktor or okhttp. Let’s roll with okhttp for now.

First, grab the library in your build.gradle:

dependencies {
    implementation("com.squareup.okhttp3:okhttp:4.9.0")
}

Time to code:

import okhttp3.Credentials
import okhttp3.OkHttpClient
import okhttp3.Request
import java.io.IOException

fun main() {
    val client = OkHttpClient()

    val username = "admin"
    val password = "password123"
    val credentials = Credentials.basic(username, password)

    val request = Request.Builder()
        .url("http://example.com/resource")
        .header("Authorization", credentials)
        .build()

    client.newCall(request).execute().use { response ->
        if (!response.isSuccessful) throw IOException("Unexpected code $response")

        println(response.body!!.string())
    }
}

Hit run and watch your console. You should see the secured resource spill out.

Deep Dive

Back in the day, HTTP Basic Auth was the go-to. Simple: just base64 the username:password and plop it in the header. Not secure alone, hence HTTPS joined the party.

Alternatives? Plenty. OAuth for tokens, API keys for simplicity, or digest authentication for an upgrade. Basic auth is good to start or for internal tools, but not for the modern, security-conscious web.

Implementation detail: Don’t invent the wheel. Libraries handle encoding and protocol nuances. OkHttp even deals with retries and connections for you. Remember, basic auth over HTTP is a no-go—always use HTTPS to keep credentials safe in transit.

See Also

Sending an HTTP request