Merge pull request #10312 from birarda/upload-new-models-to-entity

add an entity file replacement via domain-server content page

assignment-client/src/octree/OctreeServer.cpp

@@ -11,12 +11,14 @@
 
 #include "OctreeServer.h"
 
+#include <QJsonDocument>
 #include <QJsonObject>
 #include <QTimer>
 
 #include <time.h>
 
 #include <AccountManager.h>
+#include <Gzip.h>
 #include <HTTPConnection.h>
 #include <LogHandler.h>
 #include <shared/NetworkUtils.h>
@@ -924,6 +926,57 @@ void OctreeServer::handleJurisdictionRequestPacket(QSharedPointer<ReceivedMessag
     _jurisdictionSender->queueReceivedPacket(message, senderNode);
 }
 
+void OctreeServer::handleOctreeFileReplacement(QSharedPointer<ReceivedMessage> message) {
+    if (!_isFinished && !_isShuttingDown) {
+        // these messages are only allowed to come from the domain server, so make sure that is the case
+        auto nodeList = DependencyManager::get<NodeList>();
+        if (message->getSenderSockAddr() == nodeList->getDomainHandler().getSockAddr()) {
+            // it's far cleaner to load up the new content upon server startup
+            // so here we just store a special file at our persist path
+            // and then force a stop of the server so that it can pick it up when it relaunches
+            if (!_persistAbsoluteFilePath.isEmpty()) {
+
+                // before we restart the server and make it try and load this data, let's make sure it is valid
+                auto compressedOctree = message->getMessage();
+                QByteArray jsonOctree;
+
+                // assume we have GZipped content
+                bool wasCompressed = gunzip(compressedOctree, jsonOctree);
+                if (!wasCompressed) {
+                    // the source was not compressed, assume we were sent regular JSON data
+                    jsonOctree = compressedOctree;
+                }
+
+                // check the JSON data to verify it is an object
+                if (QJsonDocument::fromJson(jsonOctree).isObject()) {
+                    if (!wasCompressed) {
+                        // source was not compressed, we compress it before we write it locally
+                        gzip(jsonOctree, compressedOctree);
+                    }
+
+                    // write the compressed octree data to a special file
+                    auto replacementFilePath = _persistAbsoluteFilePath.append(OctreePersistThread::REPLACEMENT_FILE_EXTENSION);
+                    QFile replacementFile(replacementFilePath);
+                    if (replacementFile.open(QIODevice::WriteOnly) && replacementFile.write(compressedOctree) != -1) {
+                        // we've now written our replacement file, time to take the server down so it can
+                        // process it when it comes back up
+                        qInfo() << "Wrote octree replacement file to" << replacementFilePath << "- stopping server";
+                        setFinished(true);
+                    } else {
+                        qWarning() << "Could not write replacement octree data to file - refusing to process";
+                    }
+                } else {
+                    qDebug() << "Received replacement octree file that is invalid - refusing to process";
+                }
+            } else {
+                qDebug() << "Cannot perform octree file replacement since current persist file path is not yet known";
+            }
+        } else {
+            qDebug() << "Received an octree file replacement that was not from our domain server - refusing to process";
+        }
+    }
+}
+
 bool OctreeServer::readOptionBool(const QString& optionName, const QJsonObject& settingsSectionObject, bool& result) {
     result = false; // assume it doesn't exist
     bool optionAvailable = false;
@@ -1148,6 +1201,7 @@ void OctreeServer::domainSettingsRequestComplete() {
     packetReceiver.registerListener(getMyQueryMessageType(), this, "handleOctreeQueryPacket");
     packetReceiver.registerListener(PacketType::OctreeDataNack, this, "handleOctreeDataNackPacket");
     packetReceiver.registerListener(PacketType::JurisdictionRequest, this, "handleJurisdictionRequestPacket");
+    packetReceiver.registerListener(PacketType::OctreeFileReplacement, this, "handleOctreeFileReplacement");
     
     readConfiguration();
     
@@ -1173,25 +1227,25 @@ void OctreeServer::domainSettingsRequestComplete() {
         // If persist filename does not exist, let's see if there is one beside the application binary
         // If there is, let's copy it over to our target persist directory
         QDir persistPath { _persistFilePath };
-        QString persistAbsoluteFilePath = persistPath.absolutePath();
+        _persistAbsoluteFilePath = persistPath.absolutePath();
 
         if (persistPath.isRelative()) {
             // if the domain settings passed us a relative path, make an absolute path that is relative to the
             // default data directory
-            persistAbsoluteFilePath = QDir(PathUtils::getAppDataFilePath("entities/")).absoluteFilePath(_persistFilePath);
+            _persistAbsoluteFilePath = QDir(PathUtils::getAppDataFilePath("entities/")).absoluteFilePath(_persistFilePath);
         }
 
         static const QString ENTITY_PERSIST_EXTENSION = ".json.gz";
 
         // force the persist file to end with .json.gz
-        if (!persistAbsoluteFilePath.endsWith(ENTITY_PERSIST_EXTENSION, Qt::CaseInsensitive)) {
+        if (!_persistAbsoluteFilePath.endsWith(ENTITY_PERSIST_EXTENSION, Qt::CaseInsensitive)) {
-            persistAbsoluteFilePath += ENTITY_PERSIST_EXTENSION;
+            _persistAbsoluteFilePath += ENTITY_PERSIST_EXTENSION;
         } else {
             // make sure the casing of .json.gz is correct
-            persistAbsoluteFilePath.replace(ENTITY_PERSIST_EXTENSION, ENTITY_PERSIST_EXTENSION, Qt::CaseInsensitive);
+            _persistAbsoluteFilePath.replace(ENTITY_PERSIST_EXTENSION, ENTITY_PERSIST_EXTENSION, Qt::CaseInsensitive);
         }
 
-        if (!QFile::exists(persistAbsoluteFilePath)) {
+        if (!QFile::exists(_persistAbsoluteFilePath)) {
             qDebug() << "Persist file does not exist, checking for existence of persist file next to application";
 
             static const QString OLD_DEFAULT_PERSIST_FILENAME = "resources/models.json.gz";
@@ -1217,7 +1271,7 @@ void OctreeServer::domainSettingsRequestComplete() {
                 pathToCopyFrom = oldDefaultPersistPath;
             }
 
-            QDir persistFileDirectory { QDir::cleanPath(persistAbsoluteFilePath + "/..") };
+            QDir persistFileDirectory { QDir::cleanPath(_persistAbsoluteFilePath + "/..") };
 
             if (!persistFileDirectory.exists()) {
                 qDebug() << "Creating data directory " << persistFileDirectory.absolutePath();
@@ -1225,15 +1279,15 @@ void OctreeServer::domainSettingsRequestComplete() {
             }
 
             if (shouldCopy) {
-                qDebug() << "Old persist file found, copying from " << pathToCopyFrom << " to " << persistAbsoluteFilePath;
+                qDebug() << "Old persist file found, copying from " << pathToCopyFrom << " to " << _persistAbsoluteFilePath;
 
-                QFile::copy(pathToCopyFrom, persistAbsoluteFilePath);
+                QFile::copy(pathToCopyFrom, _persistAbsoluteFilePath);
             } else {
                 qDebug() << "No existing persist file found";
             }
         }
 
-        auto persistFileDirectory = QFileInfo(persistAbsoluteFilePath).absolutePath();
+        auto persistFileDirectory = QFileInfo(_persistAbsoluteFilePath).absolutePath();
         if (_backupDirectoryPath.isEmpty()) {
             // Use the persist file's directory to store backups
             _backupDirectoryPath = persistFileDirectory;
@@ -1264,7 +1318,7 @@ void OctreeServer::domainSettingsRequestComplete() {
         qDebug() << "Backups will be stored in: " << _backupDirectoryPath;
         
         // now set up PersistThread
-        _persistThread = new OctreePersistThread(_tree, persistAbsoluteFilePath, _backupDirectoryPath, _persistInterval,
+        _persistThread = new OctreePersistThread(_tree, _persistAbsoluteFilePath, _backupDirectoryPath, _persistInterval,
                                                  _wantBackup, _settings, _debugTimestampNow, _persistAsFileType);
         _persistThread->initialize(true);
     }

assignment-client/src/octree/OctreeServer.h

@@ -136,6 +136,7 @@ private slots:
     void handleOctreeQueryPacket(QSharedPointer<ReceivedMessage> message, SharedNodePointer senderNode);
     void handleOctreeDataNackPacket(QSharedPointer<ReceivedMessage> message, SharedNodePointer senderNode);
     void handleJurisdictionRequestPacket(QSharedPointer<ReceivedMessage> message, SharedNodePointer senderNode);
+    void handleOctreeFileReplacement(QSharedPointer<ReceivedMessage> message);
     void removeSendThread();
 
 protected:
@@ -172,6 +173,7 @@ protected:
     QString _statusHost;
 
     QString _persistFilePath;
+    QString _persistAbsoluteFilePath;
     QString _persistAsFileType;
     QString _backupDirectoryPath;
     int _packetsPerClientPerInterval;

domain-server/resources/web/content/index.shtml

@@ -0,0 +1,44 @@
+<!--#include virtual="header.html"-->
+
+<div class="col-md-10 col-md-offset-1">
+  <div class="row">
+    <div class="col-xs-12">
+      <div class="alert" style="display:none;"></div>
+    </div>
+  </div>
+
+  <div class="row">
+    <div class="col-xs-12">
+      <div class="panel panel-default">
+        <div class="panel-heading">
+          <h3 class="panel-title">Upload Entities File</h3>
+        </div>
+        <form id="upload-form" action="upload" enctype="multipart/form-data" method="post">
+          <div class="panel-body">
+            <p>
+              Upload an entities file (e.g.: models.json.gz) to replace the content of this domain.<br>
+              Note: <strong>Your domain's content will be replaced by the content you upload</strong>, but the backup files of your domain's content will not immediately be changed.
+            </p>
+            <p>
+              If your domain has any content that you would like to re-use at a later date, save a manual backup of your models.json.gz file, which is usually stored at the following paths:<br>
+              <pre>C:\Users\[username]\AppData\Roaming\High Fidelity\assignment-client/entities/models.json.gz</pre>
+              <pre>/Users/[username]/Library/Application Support/High Fidelity/assignment-client/entities/models.json.gz</pre>
+              <pre>/home/[username]/.local/share/High Fidelity/assignment-client/entities/models.json.gz</pre>
+            </p>
+            <br>
+            <input type="file" name="entities-file" class="form-control-file" accept=".json, .gz">
+            <br>
+          </div>
+          <div class="panel-footer">
+            <input type="submit" class="btn btn-info" value="Upload">
+          </div>
+        </form>
+      </div>
+    </div>
+  </div>
+</div>
+
+<!--#include virtual="footer.html"-->
+<script src='js/content.js'></script>
+<script src='/js/sweetalert.min.js'></script>
+<!--#include virtual="page-end.html"-->

domain-server/resources/web/content/js/content.js

@@ -0,0 +1,45 @@
+$(document).ready(function(){
+
+  function showSpinnerAlert(title) {
+    swal({
+      title: title,
+      text: '<div class="spinner" style="color:black;"><div class="bounce1"></div><div class="bounce2"></div><div class="bounce3"></div></div>',
+      html: true,
+      showConfirmButton: false,
+      allowEscapeKey: false
+    });
+  }
+
+  var frm = $('#upload-form');
+  frm.submit(function (ev) {
+    $.ajax({
+      type: frm.attr('method'),
+      url: frm.attr('action'),
+      data: new FormData($(this)[0]),
+      cache: false,
+      contentType: false,
+      processData: false,
+      success: function (data) {
+        swal({
+          title: 'Uploaded',
+          type: 'success',
+          text: 'Your Entity Server is restarting to replace its local content with the uploaded file.',
+          confirmButtonText: 'OK'
+        })
+      },
+      error: function (data) {
+        swal({
+          title: '',
+          type: 'error',
+          text: 'Your entities file could not be transferred to the Entity Server.</br>Verify that the file is a <i>.json</i> or <i>.json.gz</i> entities file and try again.',
+          html: true,
+          confirmButtonText: 'OK',
+        });
+      }
+    });
+
+    ev.preventDefault();
+
+    showSpinnerAlert("Uploading Entities File");
+  });
+});

domain-server/resources/web/header.html

@@ -36,6 +36,7 @@
                   <li><a href="/assignment">New Assignment</a></li>
                 </ul>
             </li>
+            <li><a href="/content/">Content</a></li>
             <li><a href="/settings/">Settings</a></li>
           </ul>
         </div>

domain-server/resources/web/settings/index.shtml

@@ -99,7 +99,7 @@
 <script src='/js/underscore-keypath.min.js'></script>
 <script src='/js/bootbox.min.js'></script>
 <script src='js/bootstrap-switch.min.js'></script>
-<script src='js/sweetalert.min.js'></script>
+<script src='/js/sweetalert.min.js'></script>
 <script src='js/settings.js'></script>
 <script src='js/form2js.min.js'></script>
 <script src='js/sha256.js'></script>

domain-server/src/DomainServer.cpp

@@ -1633,6 +1633,15 @@ QString pathForAssignmentScript(const QUuid& assignmentUUID) {
     return directory.absoluteFilePath(uuidStringWithoutCurlyBraces(assignmentUUID));
 }
 
+QString DomainServer::pathForRedirect(QString path) const {
+    // make sure the passed path has a leading slash
+    if (!path.startsWith('/')) {
+        path.insert(0, '/');
+    }
+
+    return "http://" + _hostname + ":" + QString::number(_httpManager.serverPort()) + path;
+}
+
 const QString URI_OAUTH = "/oauth";
 bool DomainServer::handleHTTPRequest(HTTPConnection* connection, const QUrl& url, bool skipSubHandler) {
     const QString JSON_MIME_TYPE = "application/json";
@@ -1640,6 +1649,7 @@ bool DomainServer::handleHTTPRequest(HTTPConnection* connection, const QUrl& url
     const QString URI_ASSIGNMENT = "/assignment";
     const QString URI_NODES = "/nodes";
     const QString URI_SETTINGS = "/settings";
+    const QString URI_ENTITY_FILE_UPLOAD = "/content/upload";
 
     const QString UUID_REGEX_STRING = "[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}";
 
@@ -1869,6 +1879,25 @@ bool DomainServer::handleHTTPRequest(HTTPConnection* connection, const QUrl& url
             // respond with a 200 code for successful upload
             connection->respond(HTTPConnection::StatusCode200);
 
+            return true;
+        } else if (url.path() == URI_ENTITY_FILE_UPLOAD) {
+            // this is an entity file upload, ask the HTTPConnection to parse the data
+            QList<FormData> formData = connection->parseFormData();
+
+            Headers redirectHeaders;
+
+            if (formData.size() > 0 && formData[0].second.size() > 0) {
+                // invoke our method to hand the new octree file off to the octree server
+                QMetaObject::invokeMethod(this, "handleOctreeFileReplacement",
+                                          Qt::QueuedConnection, Q_ARG(QByteArray, formData[0].second));
+
+                // respond with a 200 for success
+                connection->respond(HTTPConnection::StatusCode200);
+            } else {
+                // respond with a 400 for failure
+                connection->respond(HTTPConnection::StatusCode400);
+            }
+
             return true;
         }
     } else if (connection->requestOperation() == QNetworkAccessManager::DeleteOperation) {
@@ -2159,8 +2188,7 @@ Headers DomainServer::setupCookieHeadersFromProfileReply(QNetworkReply* profileR
     cookieHeaders.insert("Set-Cookie", cookieString.toUtf8());
 
     // redirect the user back to the homepage so they can present their cookie and be authenticated
-    QString redirectString = "http://" + _hostname + ":" + QString::number(_httpManager.serverPort());
+    cookieHeaders.insert("Location", pathForRedirect().toUtf8());
-    cookieHeaders.insert("Location", redirectString.toUtf8());
 
     return cookieHeaders;
 }
@@ -2560,3 +2588,20 @@ void DomainServer::setupGroupCacheRefresh() {
         _metaverseGroupCacheTimer->start(REFRESH_GROUPS_INTERVAL_MSECS);
     }
 }
+
+void DomainServer::handleOctreeFileReplacement(QByteArray octreeFile) {
+    // enumerate the nodes and find any octree type servers with active sockets
+
+    auto limitedNodeList = DependencyManager::get<LimitedNodeList>();
+    limitedNodeList->eachMatchingNode([](const SharedNodePointer& node) {
+        return node->getType() == NodeType::EntityServer && node->getActiveSocket();
+    }, [&octreeFile, limitedNodeList](const SharedNodePointer& octreeNode) {
+        // setup a packet to send to this octree server with the new octree file data
+        auto octreeFilePacketList = NLPacketList::create(PacketType::OctreeFileReplacement, QByteArray(), true, true);
+        octreeFilePacketList->write(octreeFile);
+
+        qDebug() << "Sending an octree file replacement of" << octreeFile.size() << "bytes to" << octreeNode;
+
+        limitedNodeList->sendPacketList(std::move(octreeFilePacketList), *octreeNode);
+    });
+}

domain-server/src/DomainServer.h

@@ -100,6 +100,8 @@ private slots:
     void handleSuccessfulICEServerAddressUpdate(QNetworkReply& requestReply);
     void handleFailedICEServerAddressUpdate(QNetworkReply& requestReply);
 
+    void handleOctreeFileReplacement(QByteArray octreeFile);
+
 signals:
     void iceServerChanged();
     void userConnected();
@@ -161,6 +163,8 @@ private:
 
     void setupGroupCacheRefresh();
 
+    QString pathForRedirect(QString path = QString()) const;
+
     SubnetList _acSubnetWhitelist;
 
     DomainGatekeeper _gatekeeper;

interface/src/Application.cpp

@@ -798,7 +798,7 @@ Application::Application(int& argc, char** argv, QElapsedTimer& startupTimer, bo
     connect(&domainHandler, SIGNAL(resetting()), SLOT(resettingDomain()));
     connect(&domainHandler, SIGNAL(connectedToDomain(const QString&)), SLOT(updateWindowTitle()));
     connect(&domainHandler, SIGNAL(disconnectedFromDomain()), SLOT(updateWindowTitle()));
-    connect(&domainHandler, SIGNAL(disconnectedFromDomain()), SLOT(clearDomainOctreeDetails()));
+    connect(&domainHandler, &DomainHandler::disconnectedFromDomain, this, &Application::clearDomainAvatars);
     connect(&domainHandler, &DomainHandler::disconnectedFromDomain, this, [this]() {
         getOverlays().deleteOverlay(getTabletScreenID());
         getOverlays().deleteOverlay(getTabletHomeButtonID());
@@ -5179,7 +5179,6 @@ void Application::clearDomainOctreeDetails() {
     qCDebug(interfaceapp) << "Clearing domain octree details...";
 
     resetPhysicsReadyInformation();
-    getMyAvatar()->setAvatarEntityDataChanged(true); // to recreate worn entities
 
     // reset our node to stats and node to jurisdiction maps... since these must be changing...
     _entityServerJurisdictions.withWriteLock([&] {
@@ -5198,14 +5197,18 @@ void Application::clearDomainOctreeDetails() {
     skyStage->setBackgroundMode(model::SunSkyStage::SKY_DEFAULT);
 
     _recentlyClearedDomain = true;
-
+    
-    DependencyManager::get<AvatarManager>()->clearOtherAvatars();
     DependencyManager::get<AnimationCache>()->clearUnusedResources();
     DependencyManager::get<ModelCache>()->clearUnusedResources();
     DependencyManager::get<SoundCache>()->clearUnusedResources();
     DependencyManager::get<TextureCache>()->clearUnusedResources();
 }
 
+void Application::clearDomainAvatars() {
+    getMyAvatar()->setAvatarEntityDataChanged(true); // to recreate worn entities
+    DependencyManager::get<AvatarManager>()->clearOtherAvatars();
+}
+
 void Application::domainChanged(const QString& domainHostname) {
     updateWindowTitle();
     // disable physics until we have enough information about our new location to not cause craziness.
@@ -5275,33 +5278,8 @@ void Application::nodeKilled(SharedNodePointer node) {
     if (node->getType() == NodeType::AudioMixer) {
         QMetaObject::invokeMethod(DependencyManager::get<AudioClient>().data(), "audioMixerKilled");
     } else if (node->getType() == NodeType::EntityServer) {
-        QUuid nodeUUID = node->getUUID();
+        // we lost an entity server, clear all of the domain octree details
-        // see if this is the first we've heard of this node...
+        clearDomainOctreeDetails();
-        _entityServerJurisdictions.withReadLock([&] {
-            if (_entityServerJurisdictions.find(nodeUUID) == _entityServerJurisdictions.end()) {
-                return;
-            }
-
-            auto rootCode = _entityServerJurisdictions[nodeUUID].getRootOctalCode();
-            VoxelPositionSize rootDetails;
-            voxelDetailsForCode(rootCode.get(), rootDetails);
-
-            qCDebug(interfaceapp, "model server going away...... v[%f, %f, %f, %f]",
-                (double)rootDetails.x, (double)rootDetails.y, (double)rootDetails.z, (double)rootDetails.s);
-
-        });
-
-        // If the model server is going away, remove it from our jurisdiction map so we don't send voxels to a dead server
-        _entityServerJurisdictions.withWriteLock([&] {
-            _entityServerJurisdictions.erase(_entityServerJurisdictions.find(nodeUUID));
-        });
-
-        // also clean up scene stats for that server
-        _octreeServerSceneStats.withWriteLock([&] {
-            if (_octreeServerSceneStats.find(nodeUUID) != _octreeServerSceneStats.end()) {
-                _octreeServerSceneStats.erase(nodeUUID);
-            }
-        });
     } else if (node->getType() == NodeType::AvatarMixer) {
         // our avatar mixer has gone away - clear the hash of avatars
         DependencyManager::get<AvatarManager>()->clearOtherAvatars();

interface/src/Application.h

@@ -409,6 +409,7 @@ public slots:
 private slots:
     void showDesktop();
     void clearDomainOctreeDetails();
+    void clearDomainAvatars();
     void aboutToQuit();
 
     void resettingDomain();

libraries/networking/src/udt/PacketHeaders.cpp

@@ -39,7 +39,7 @@ const QSet<PacketType> NON_SOURCED_PACKETS = QSet<PacketType>()
     << PacketType::ICEServerPeerInformation << PacketType::ICEServerQuery << PacketType::ICEServerHeartbeat
     << PacketType::ICEServerHeartbeatACK << PacketType::ICEPing << PacketType::ICEPingReply
     << PacketType::ICEServerHeartbeatDenied << PacketType::AssignmentClientStatus << PacketType::StopNode
-    << PacketType::DomainServerRemovedNode << PacketType::UsernameFromIDReply;
+    << PacketType::DomainServerRemovedNode << PacketType::UsernameFromIDReply << PacketType::OctreeFileReplacement;
 
 PacketVersion versionForPacketType(PacketType packetType) {
     switch (packetType) {

libraries/networking/src/udt/PacketHeaders.h

@@ -113,7 +113,8 @@ public:
         EntityPhysics,
         EntityServerScriptLog,
         AdjustAvatarSorting,
-        LAST_PACKET_TYPE = AdjustAvatarSorting
+        OctreeFileReplacement,
+        LAST_PACKET_TYPE = OctreeFileReplacement
     };
 };
 

libraries/octree/src/OctreePersistThread.cpp

@@ -33,6 +33,7 @@
 #include "OctreePersistThread.h"
 
 const int OctreePersistThread::DEFAULT_PERSIST_INTERVAL = 1000 * 30; // every 30 seconds
+const QString OctreePersistThread::REPLACEMENT_FILE_EXTENSION = ".replace";
 
 OctreePersistThread::OctreePersistThread(OctreePointer tree, const QString& filename, const QString& backupDirectory, int persistInterval,
                                          bool wantBackup, const QJsonObject& settings, bool debugTimestampNow,
@@ -131,10 +132,47 @@ quint64 OctreePersistThread::getMostRecentBackupTimeInUsecs(const QString& forma
     return mostRecentBackupInUsecs;
 }
 
+void OctreePersistThread::possiblyReplaceContent() {
+    // before we load the normal file, check if there's a pending replacement file
+    auto replacementFileName = _filename + REPLACEMENT_FILE_EXTENSION;
+
+    QFile replacementFile { replacementFileName };
+    if (replacementFile.exists()) {
+        // we have a replacement file to process
+        qDebug() << "Replacing models file with" << replacementFileName;
+
+        // first take the current models file and move it to a different filename, appended with the timestamp
+        QFile currentFile { _filename };
+        if (currentFile.exists()) {
+            static const QString FILENAME_TIMESTAMP_FORMAT = "yyyyMMdd-hhmmss";
+            auto backupFileName = _filename + ".backup." + QDateTime::currentDateTime().toString(FILENAME_TIMESTAMP_FORMAT);
+
+            if (currentFile.rename(backupFileName)) {
+                qDebug() << "Moved previous models file to" << backupFileName;
+            } else {
+                qWarning() << "Could not backup previous models file to" << backupFileName << "- removing replacement models file";
+
+                if (!replacementFile.remove()) {
+                    qWarning() << "Could not remove replacement models file from" << replacementFileName
+                        << "- replacement will be re-attempted on next server restart";
+                    return;
+                }
+            }
+        }
+
+        // rename the replacement file to match what the persist thread is just about to read
+        if (!replacementFile.rename(_filename)) {
+            qWarning() << "Could not replace models file with" << replacementFileName << "- starting with empty models file";
+        }
+    }
+}
+
 
 bool OctreePersistThread::process() {
 
     if (!_initialLoadComplete) {
+        possiblyReplaceContent();
+
         quint64 loadStarted = usecTimestampNow();
         qCDebug(octree) << "loading Octrees from file: " << _filename << "...";
 

libraries/octree/src/OctreePersistThread.h

@@ -32,6 +32,7 @@ public:
     };
 
     static const int DEFAULT_PERSIST_INTERVAL;
+    static const QString REPLACEMENT_FILE_EXTENSION;
 
     OctreePersistThread(OctreePointer tree, const QString& filename, const QString& backupDirectory,
                         int persistInterval = DEFAULT_PERSIST_INTERVAL, bool wantBackup = false,
@@ -60,6 +61,7 @@ protected:
     bool getMostRecentBackup(const QString& format, QString& mostRecentBackupFileName, QDateTime& mostRecentBackupTime);
     quint64 getMostRecentBackupTimeInUsecs(const QString& format);
     void parseSettings(const QJsonObject& settings);
+    void possiblyReplaceContent();
 
 private:
     OctreePointer _tree;