Handle network error during proxy config better.

Don't assume we need a proxy and show the user an inscrutable dialog. Pop up a
dialog that says that we were unable to connect and tell them to check their
internet connection. From there they can either try again or configure a proxy
if they know that's a thing they might need to do.

launcher/src/main/java/com/threerings/getdown/launcher/Getdown.java

@@ -38,6 +38,7 @@ import javax.swing.AbstractAction;
 import javax.swing.JButton;
 import javax.swing.JFrame;
 import javax.swing.JLayeredPane;
+import javax.swing.JOptionPane;
 
 import com.samskivert.swing.util.SwingUtil;
 import com.threerings.getdown.data.Application;
@@ -202,11 +203,17 @@ public abstract class Getdown
         _dead = false;
         // if we fail to detect a proxy, but we're allowed to run offline, then go ahead and
         // run the app anyway because we're prepared to cope with not being able to update
+        try {
             if (detectProxy() || _app.allowOffline()) getdown();
             else requestProxyInfo(false);
+        } catch (IOException ioe) {
+            log.info("Failed to detect if proxy is needed", "error", ioe);
+            log.info("We may need a proxy, or maybe their network is down.");
+            showConnectionFailedDialog();
+        }
     }
 
-    protected boolean detectProxy () {
+    protected boolean detectProxy () throws IOException {
         // first we have to initialize our application to get the appbase URL, etc.
         log.info("Checking whether we need to use a proxy...");
         try {
@@ -223,6 +230,7 @@ public abstract class Getdown
         // see if we actually need a proxy
         updateStatus("m.detecting_proxy");
         URL configURL = _app.getConfigResource().getRemote();
+        // if this detection fails to connect, we'll let the IOException propagate out
         if (!ProxyUtil.canLoadWithoutProxy(configURL, tryNoProxy ? 2 : 5)) {
             // if we didn't auto-detect proxy first thing, do auto-detect now
             return tryNoProxy ? ProxyUtil.autoDetectProxy(_app) : false;
@@ -262,6 +270,33 @@ public abstract class Getdown
         showContainer();
     }
 
+    /**
+     * Shows a dialog informing the user that we could not connect to the download servers,
+     * with buttons to try again or configure a proxy.
+     */
+    protected void showConnectionFailedDialog () {
+        if (_silent) {
+            log.warning("Unable to connect to download servers. Exiting.");
+            return;
+        }
+
+        String message = _msgs.getString("m.proxy_connect_failed");
+        String tryAgain = _msgs.getString("m.try_again");
+        String configureProxy = _msgs.getString("m.configure_proxy_button");
+        Object[] options = { tryAgain, configureProxy };
+        int choice = JOptionPane.showOptionDialog(
+            null, message, "",
+            JOptionPane.YES_NO_OPTION, JOptionPane.WARNING_MESSAGE,
+            null, options, options[0]);
+        if (choice == JOptionPane.YES_OPTION) {
+            // "Try again" — re-run the update/launch sequence
+            run();
+        } else if (choice == JOptionPane.NO_OPTION) {
+            // "Configure proxy" — show the proxy configuration panel
+            requestProxyInfo(false);
+        }
+    }
+
     /**
      * Downloads and installs (without verifying) any resources that are marked with a
      * {@code PRELOAD} attribute.

launcher/src/main/java/com/threerings/getdown/launcher/ProxyUtil.java

@@ -124,9 +124,9 @@ public final class ProxyUtil {
     }
 
     public static boolean canLoadWithoutProxy (URL rurl, int timeoutSeconds)
+      throws IOException
     {
         log.info("Attempting to fetch without proxy: " + rurl);
-        try {
         URLConnection conn = Connector.DEFAULT.open(rurl, timeoutSeconds, timeoutSeconds);
         // if the appbase is not an HTTP/S URL (like file:), then we don't need a proxy
         if (!(conn instanceof HttpURLConnection)) {
@@ -142,17 +142,13 @@ public final class ProxyUtil {
             if (rcode == HttpURLConnection.HTTP_PROXY_AUTH ||
                 rcode == HttpURLConnection.HTTP_FORBIDDEN) {
                 log.warning("Got an 'HTTP credentials needed' response", "code", rcode);
+                return false;
             } else {
                 return true;
             }
         } finally {
             hcon.disconnect();
         }
-        } catch (IOException ioe) {
-            log.info("Failed to HEAD " + rurl + ": " + ioe);
-            log.info("We probably need a proxy, but auto-detection failed.");
-        }
-        return false;
     }
 
     public static void configProxy (Application app, String host, String port,

launcher/src/main/resources/com/threerings/getdown/messages.properties

@@ -11,6 +11,10 @@ m.abort_cancel = Continue installation
 
 m.detecting_proxy = Trying to auto-detect proxy settings
 
+m.proxy_connect_failed = We were unable to connect to the download servers. Please check your Internet connection.
+m.try_again = Try again
+m.configure_proxy_button = Configure proxy
+
 m.configure_proxy = <html>We were unable to connect to the application server to download data. \
   <p> Please make sure that no virus scanner or firewall is blocking network communication with \
   the server. \