Example of using POST request to cssminifier.com to minify a css file.

CSSMinifier.kt

import java.io.File
import java.io.InputStreamReader
import java.io.OutputStreamWriter
import java.net.HttpURLConnection
import java.net.URL
import java.net.URLEncoder

fun main() {

    // Input File
    val input = File("/path/to/file.css")

    // Create Content
    val content = StringBuilder().apply {
        append(URLEncoder.encode("input", "UTF-8"))
        append("=")
        append(URLEncoder.encode(input.readText(), "UTF-8"))
    }.toString()

    // Create Request
    val request = (URL("https://cssminifier.com/raw").openConnection() as HttpURLConnection).apply {
        requestMethod = "POST"
        doOutput = true
        setRequestProperty("Content-Type", "application/x-www-form-urlencoded")
        setRequestProperty("charset", "utf-8")
        setRequestProperty("Content-Length", content.length.toString())
        OutputStreamWriter(outputStream).apply {
            write(content)
            flush()
        }
    }

    // Parse Response
    if(request.responseCode == 200) {

        // Print Result
        println(InputStreamReader(request.inputStream).readText())
    }

    // Handle Error
    else println("Error: ${request.responseCode} ${request.responseMessage}")

}