[gnome-boxes] downloader: Error out if server is unreachable

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit 575b8f14ecb19acdff1cbde7f1463dcb18d150ff
Author: Zeeshan Ali (Khattak) <zeeshanak gnome org>
Date:   Mon Dec 10 16:47:39 2012 +0200

    downloader: Error out if server is unreachable
    
    https://bugzilla.gnome.org/show_bug.cgi?id=689977

 src/downloader.vala |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/src/downloader.vala b/src/downloader.vala
index d6b0aa1..3392b1f 100644
--- a/src/downloader.vala
+++ b/src/downloader.vala
@@ -60,6 +60,12 @@ private class Boxes.Downloader : GLib.Object {
 
         try {
             var msg = new Soup.Message ("GET", uri);
+            var address = msg.get_address ();
+            var connectable = new NetworkAddress (address.name, (uint16) address.port);
+            var network_monitor = NetworkMonitor.get_default ();
+            if (!(yield network_monitor.can_reach_async (connectable)))
+                throw new Boxes.Error.INVALID ("Failed to reach host '%s' on port '%d'", address.name, address.port);
+
             session.queue_message (msg, (session, msg) => {
                 download.callback ();
             });