Limit number of internet connections, connect to random node.

android/src/main/scala/com/nutomic/ensichat/service/ChatService.scala

@@ -32,7 +32,7 @@ class ChatService extends Service {
 
   private lazy val connectionHandler =
     new ConnectionHandler(new SettingsWrapper(this), new Database(this), callbackHandler,
-                          ChatService.newCrypto(this))
+                          ChatService.newCrypto(this), 1)
 
   private val networkReceiver = new NetworkChangedReceiver()
 

core/src/main/scala/com/nutomic/ensichat/core/ConnectionHandler.scala

@@ -12,9 +12,13 @@ import scala.concurrent.ExecutionContext.Implicits.global
 
 /**
  * High-level handling of all message transfers and callbacks.
+ *
+ * @param maxInternetConnections Maximum number of concurrent connections that should be opened by
+ *                               [[InternetInterface]].
  */
 final class ConnectionHandler(settings: SettingsInterface, database: DatabaseInterface,
-                              callbacks: CallbackInterface, crypto: Crypto) {
+                              callbacks: CallbackInterface, crypto: Crypto,
+                              maxInternetConnections: Int) {
 
   private val Tag = "ConnectionHandler"
 
@@ -40,7 +44,7 @@ final class ConnectionHandler(settings: SettingsInterface, database: DatabaseInt
       Log.i(Tag, "Service started, address is " + crypto.localAddress)
       Log.i(Tag, "Local user is " + settings.get(SettingsInterface.KeyUserName, "none") +
         " with status '" + settings.get(SettingsInterface.KeyUserStatus, "") + "'")
-      transmissionInterfaces += new InternetInterface(this, crypto, settings)
+      transmissionInterfaces += new InternetInterface(this, crypto, settings, maxInternetConnections)
       transmissionInterfaces.foreach(_.create())
     }
   }

core/src/main/scala/com/nutomic/ensichat/core/internet/InternetInterface.scala

@@ -9,6 +9,7 @@ import com.nutomic.ensichat.core.util.FutureHelper
 import com.nutomic.ensichat.core.{Address, ConnectionHandler, Crypto, Message}
 
 import scala.concurrent.ExecutionContext.Implicits.global
+import scala.util.Random
 
 object InternetInterface {
 
@@ -18,9 +19,12 @@ object InternetInterface {
 
 /**
  * Handles all Internet connectivity.
+ *
+ * @param maxConnections Maximum number of concurrent connections that should be opened.
  */
 class InternetInterface(connectionHandler: ConnectionHandler, crypto: Crypto,
-                        settings: SettingsInterface) extends TransmissionInterface {
+                        settings: SettingsInterface, maxConnections: Int)
+  extends TransmissionInterface {
 
   private val Tag = "InternetInterface"
 
@@ -37,7 +41,7 @@ class InternetInterface(connectionHandler: ConnectionHandler, crypto: Crypto,
   override def create(): Unit = {
     FutureHelper {
       serverThread.start()
-      openAllConnections()
+      openAllConnections(maxConnections)
     }
   }
 
@@ -49,11 +53,15 @@ class InternetInterface(connectionHandler: ConnectionHandler, crypto: Crypto,
     connections.foreach(_.close())
   }
 
-  private def openAllConnections(): Unit =
+  private def openAllConnections(maxConnections: Int): Unit = {
-    settings.get(SettingsInterface.KeyServers, "")
+    val addresses = settings.get(SettingsInterface.KeyServers, "")
       .split(",")
       .map(_.trim())
+
+    Random.shuffle(addresses.toList)
+      .take(maxConnections)
       .foreach(openConnection)
+  }
 
   private def openConnection(addressPort: String): Unit = {
     val split = addressPort.split(":")
@@ -124,9 +132,9 @@ class InternetInterface(connectionHandler: ConnectionHandler, crypto: Crypto,
 
   def connectionChanged(): Unit = {
     FutureHelper {
-      Log.i(Tag, "Network has changed. Close all connections and connect to bootstrap nodes again")
+      Log.i(Tag, "Network has changed. Closing all connections and connecting to bootstrap nodes again")
       connections.foreach(_.close())
-      openAllConnections()
+      openAllConnections(maxConnections)
     }
   }
 

server/src/main/scala/com/nutomic/ensichat/server/Main.scala

@@ -22,7 +22,8 @@ object Main extends App with CallbackInterface {
   private lazy val logInstance       = new Logging()
   private lazy val settings          = new Settings(ConfigFile)
   private lazy val crypto            = new Crypto(settings, KeyFolder)
-  private lazy val connectionHandler = new ConnectionHandler(settings, new Database(), this, crypto)
+  private lazy val connectionHandler =
+    new ConnectionHandler(settings, new Database(), this, crypto, 7)
 
   init()