kotlin connect to self-signed https server

Question

I have the following kotlin code:

val urlPath = "https://10.0.2.2:8080"
var data: String
try {
    data = URL(urlPath).readText()
} catch (e: Exception) {
    Log.e("doInBackground", "Exception caught: ${e.localizedMessage}")
    error = when (e) {
        is MalformedURLException -> "Invalid URL"
        is IOException -> "Network Error"
        else -> {
            "Network error: ${e.localizedMessage}"
        }
    }
}

If I use the above code to connect to a http server, the above code works. However when I try to connect to a https server with a self-signed certificate, it fails. Is there a way to allow https connections on localhost (only), even when the certificates are self-signed ?

Answer 1

Here's an example that reads from https://google.com using JSSE, it trusts literally every certificate and shouldn't be used productively.

fun main(args: Array<String>) {
    val urlPath = "https://google.com"
    try {
        (URL(urlPath).openConnection() as HttpsURLConnection).apply {
            sslSocketFactory = createSocketFactory(listOf("TLSv1.2"))
            hostnameVerifier = HostnameVerifier { _, _ -> true }
            readTimeout = 5_000
        }.inputStream.use {
            it.copyTo(System.out)
        }
    } catch (e: Exception) {
        TODO()
    }
}


private fun createSocketFactory(protocols: List<String>) =
    SSLContext.getInstance(protocols[0]).apply {
        val trustAllCerts = arrayOf<TrustManager>(object : X509TrustManager {
            override fun getAcceptedIssuers(): Array<X509Certificate> = arrayOf()
            override fun checkClientTrusted(certs: Array<X509Certificate>, authType: String) = Unit
            override fun checkServerTrusted(certs: Array<X509Certificate>, authType: String) = Unit
        })
        init(null, trustAllCerts, SecureRandom())
    }.socketFactory

I've got a little library for these kinds of things here, which is neither up-to-date nor published. Nevertheless, it provides a simple DSL for setting up TLS/SSL sockets and provides means for https connections.