Try to fix #119

src/connection.cpp

@@ -71,7 +71,21 @@ void ConnectionLoader::loadConnection()
 
 void ConnectionLoader::loadProgress()
 {
-    QTimer::singleShot(1, [=]() { this->ShowProgress(); });
+    bool failed = false;
+    QTimer::singleShot(1, [=]() mutable {
+        // continually retry ShowProgress() until it succeeds
+        // by running without an exception
+        do {
+            try {
+                this->ShowProgress();
+                failed = false;
+            } catch (const std::exception& e)  {
+                DEBUG("caught exception " << e.what() );
+                failed = true;
+            }
+        } while (failed);
+
+    });
     if (!Settings::getInstance()->isHeadless())
         d->exec();
 }
@@ -85,7 +99,7 @@ void ConnectionLoader::ShowProgress()
 
     auto connection = makeConnection(config);
     auto me   = this;
-    qDebug() << __func__ << ": server=" <<  config->server << " connection=" << connection << " me=" << me;
+    DEBUG("server=" <<  config->server << " connection=" << connection << " me=" << me);
 
     isSyncing = new QAtomicInteger<bool>();
     isSyncing->store(true);
@@ -107,33 +121,36 @@ void ConnectionLoader::ShowProgress()
         // Check the sync status
         if (isSyncing != nullptr && isSyncing->load()) {
             // Get the sync status
-    
             try {
                 connection->doRPC("syncstatus", "", [=](json reply) {
-                if (isSyncing != nullptr && reply.find("synced_blocks") != reply.end())
+                    if (isSyncing != nullptr && reply.find("synced_blocks") != reply.end()) {
-    
-                {
                         qint64 synced = reply["synced_blocks"].get<json::number_unsigned_t>();
                         qint64 total = reply["total_blocks"].get<json::number_unsigned_t>();
                         me->showInformation(
                             "Syncing... " + QString::number(synced) + " / " + QString::number(total)
                         );
                     }
-            },
+                }, [=](QString err) {
-            [=](QString err) {
+                    DEBUG("Sync error " << err);
-                qDebug() << "Sync error" << err;
+                    // We may have gotten "Unexpected compression flag: 60"
+                    // or some other error, so let's try another server
+                    config->server = Settings::getRandomServer();
+                    DEBUG("Changed server to " << config->server );
                 });
-        }catch (...)
+            } catch (const std::exception& e)  {
-        {
+                DEBUG("syncstatus exception: " << e.what() );
                 main->logger->write("catch sync progress reply");
-        }
 
+                // rethrow exception so loadProgress can catch
+                // it and retry the entire ShowProgress() function again
+                throw new std::runtime_error(std::string("syncstatus failed"));
+            }
         }
-});
+    });
 
-syncTimer->setInterval(1* 1000);
+    syncTimer->setInterval(1*1000);
-syncTimer->start();
+    syncTimer->start();
-main->logger->write("Start sync timer");
+    main->logger->write("Start sync timer");
 
 }