Embed AES/RSA/SHA-1 crypto implementation

docs/Impl-HTTP-Client.md

@@ -0,0 +1,41 @@
+# Ktor based http client
+
+```kotlin
+private val httpClient = HttpClient()
+
+public val CustomProtocolContext: ProtocolContextBuilder.() -> Unit = {
+    authProvider = AuthenticationProvider { url, accessToken, uuid, serverIdHash ->
+        val status = httpClient.post(url) {
+            headers { header("Content-Type", "application/json") }
+            setBody("{\"accessToken\":\"$accessToken\", \"selectedProfile\":\"$uuid\", \"serverId\":\"$serverIdHash\"}")
+        }.status
+        require(status == HttpStatusCode.NoContent)
+    }
+}
+```
+
+# HttpURLConnection based http client
+
+```kotlin
+private fun sendJoinRequest(url: String, accessToken: String, uuid: String, serverIdHash: String): Boolean {
+    val connection = (URL(url).openConnection() as HttpURLConnection).apply {
+        requestMethod = "POST"
+        setRequestProperty("Content-Type", "application/json")
+        doOutput = true
+        connectTimeout = 5000
+        readTimeout = 5000
+    }
+    val jsonPayload = """{"accessToken":"$accessToken","selectedProfile":"$uuid","serverId":"$serverIdHash"}"""
+    connection.outputStream.use { os -> os.write(jsonPayload.toByteArray(Charsets.UTF_8)) }
+    val responseCode = connection.responseCode
+    connection.disconnect()
+    return responseCode == HttpURLConnection.HTTP_NO_CONTENT
+}
+
+public val CustomProtocolContext: ProtocolContextBuilder.() -> Unit = {
+    authProvider = AuthenticationProvider { url, accessToken, uuid, serverIdHash ->
+        val success = sendJoinRequest(url, accessToken, uuid, serverIdHash)
+        require(success) { "Failed to authenticate with Mojang session server" }
+    }
+}
+```