Debug: proxy connections

app/src/main/java/com/sun/mail/util/SocketFetcher.java

@@ -312,7 +312,7 @@ public class SocketFetcher {
 	    } else {
 				SocketFactory f = (SocketFactory) props.get("fairemail.factory");
 				eu.faircode.email.Log.i("Using socket factory=" + f);
-				socket = (f == null ? new Socket() : f.createSocket());
+				socket = (f == null ? eu.faircode.email.ConnectionHelper.getSocket(host, port) : f.createSocket());
 	    }
 	}
 	if (to >= 0) {

app/src/main/java/eu/faircode/email/ApplicationEx.java

@@ -125,6 +125,8 @@ public class ApplicationEx extends Application
                 " process=" + android.os.Process.myPid());
         Log.logMemory(this, "App");
 
+        ConnectionHelper.setupProxy(this);
+
         if (BuildConfig.DEBUG)
             UriHelper.test(this);
 

app/src/main/java/eu/faircode/email/ConnectionHelper.java

@@ -48,8 +48,12 @@ import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.InterfaceAddress;
 import java.net.NetworkInterface;
+import java.net.Proxy;
+import java.net.ProxySelector;
 import java.net.Socket;
+import java.net.SocketAddress;
 import java.net.SocketException;
+import java.net.URI;
 import java.net.URL;
 import java.net.URLDecoder;
 import java.net.UnknownHostException;
@@ -906,4 +910,32 @@ public class ConnectionHelper {
             Log.w(ex);
         }
     }
+
+    static void setupProxy(Context context) {
+        if (!BuildConfig.DEBUG)
+            return;
+
+        // https://docs.oracle.com/javase/8/docs/technotes/guides/net/proxies.html
+        ProxySelector.setDefault(new ProxySelector() {
+            @Override
+            public List<Proxy> select(URI uri) {
+                // new Proxy(Proxy.Type.SOCKS, new InetSocketAddress("", 0));
+                Log.i("PROXY uri=" + uri);
+                return Arrays.asList(Proxy.NO_PROXY);
+            }
+
+            @Override
+            public void connectFailed(URI uri, SocketAddress sa, IOException ex) {
+                Log.e("PROXY uri=" + uri + " sa=" + sa, ex);
+            }
+        });
+    }
+
+    public static Socket getSocket(String host, int port) {
+        if (BuildConfig.DEBUG) {
+            Proxy proxy = ProxySelector.getDefault().select(URI.create("socket://" + host + ":" + port)).get(0);
+            return new Socket(proxy);
+        } else
+            return new Socket();
+    }
 }

app/src/main/java/eu/faircode/email/Whois.java

@@ -42,7 +42,7 @@ public class Whois {
     }
 
     static String get(String domain, String host, int port) throws IOException {
-        Socket socket = new Socket();
+        Socket socket = ConnectionHelper.getSocket(host, port);
         socket.connect(new InetSocketAddress(host, port), WHOIS_TIMEOUT);
         try {
             byte[] request = (domain + "\r\n").getBytes(StandardCharsets.UTF_8);