Administering Liferay Sync

Liferay Sync is an add-on product for Liferay 6.2 CE and EE that synchronizes files between your Liferay server and users’ desktop and mobile environments. With Liferay Sync, users can publish and access shared documents and files from their native environments without using a browser. Clients for Windows and Mac OS desktops and Android and iOS mobile platforms are supported. As users add and collaborate on documents and files, Liferay Sync automatically synchronizes them across all configured Sync clients and in your portal. Liferay Sync integrates completely with the Liferay Platform so that features such as authentication and versioning function in the supported environments. The Liferay Sync desktop client stores files locally so they’re always available, even when users are offline. It automatically synchronizes files upon client reconnection. The Liferay Sync mobile client saves storage space on users’ devices by downloading only the files they choose.

This guide walks you through setting up Sync for your portal and its sites. In addition to basic portal configuration, important topics such as portal security and accidental data loss are covered. Note, you must be an administrator to set up your portal for Sync. If you’re not a portal or site administrator, you can skip this guide and move on to installing and using the Sync desktop client.

To prepare your portal for Sync, you must first install the Sync Connector plugin.

Installing the Sync Connector Plugin

Prior to Liferay 6.2, Liferay Portal’s Documents and Media services contained all the logic Liferay Sync used. As of Liferay 6.2, the Sync Connector plugin instead contains the logic Sync requires. On Liferay 6.2, you must therefore install this plugin. Even though Liferay Portal 6.2 includes the Sync Connector Web plugin (an older version of the Sync Connector plugin), you must use the new Sync Connector plugin for Sync to work properly. The new Sync clients also require the latest Sync Connector plugin. To get the new Sync Connector plugin, search for sync on the Liferay Marketplace, and download the version of the plugin that matches your portal’s version and edition. Note, older Sync 1.x clients can’t connect to the new Sync Connector plugin.

Sync Connector contains two applications: Sync Web (sync-web) and Sync Admin (sync-admin-portlet). Sync Web transparently provides Sync’s functional logic. Sync Admin’s provides a UI that lets you control how Sync clients function with your portal. For example, you can disable Sync across the portal or on a site-by-site basis. Sync Connector installs the same as any other Liferay plugin. Once you’ve installed Sync, it’s enabled by default for all the portal’s sites, so you can start using it.

If you want to use Sync Admin’s default settings, are fine with Sync being enabled for all the portal’s sites, and aren’t using SSO (single sign-on), you can skip the next two sections. Before directing your users to install and configure the Sync desktop and mobile clients, however, Make sure to read this guide’s sections on preventing accidental file deletion and ensuring Sync security, and warn your users about the potential for accidental data loss.

Configuring Sync to Use SSO

If your portal uses a SSO (single sign-on) server, there are some steps you must take to ensure that Sync can work properly. First, you must be running Liferay EE. To work with SSO, Sync requires Liferay’s EE-only OAuth Provider app. This app is included with the Sync Connector EE app. Make sure that you don’t undeploy OAuth Provider if you plan to use Sync with SSO. You must also enable OAuth in the Sync Admin app. The next section discusses this.

You must also ensure that Sync can access the following URLs without being redirected to your SSO server. Sync can’t work without direct access to these URLs. You must therefore whitelist these URLs in your web server:


For example, if your portal’s address is, then you must whitelist the following URLs in your web server:***

Sync uses the paths specified in the first URL for communication via OAuth, and the paths specified in the remaining URLs for normal communication with your portal.

Next, you’ll learn how to use Sync Admin to configure Sync.

Using Sync Admin to Configure Liferay Sync

Sync Admin’s UI lets you enable or disable Sync across the portal or for specific sites. You can also configure default file permissions on a per-site basis. Sync Admin is accessible in the Control Panel’s Configuration section.

Figure 5.11: The Control Panels Configuration section contains the Sync Admin portlet.

Figure 5.11: The Control Panel's Configuration section contains the Sync Admin portlet.

Sync Admin has two tabs: Settings and Sites. The Settings tab has General and Advanced settings that apply globally to Sync. In General settings, you can disable Sync for all sites by unchecking the checkbox Allow the use of Sync?. You can also disable user personal sites from syncing by unchecking the checkbox Allow users to sync their personal sites?. Sync is enabled by default on all these sites.

The Advanced section in Settings lets you tune the portal’s data exchange with Sync clients. To enable OAuth, and therefore SSO, check OAuth Enabled. Note that to enable OAuth here, you must be running Liferay EE and the OAuth Provider app. Next, the Max Connections value specifies the maximum number of simultaneous connections each client is allowed per account. For example, if Max Connections is three, a client can simultaneously upload or download up to three files for each account. Note, this setting operates on a per client basis. If the Max Connections is set to three and a user has two clients connected to an account (which is possible if Sync is installed on two different machines), then the user is effectively allowed six simultaneous connections. While increasing Max Connections can speed up file transfers it also places a heavier load on the server. Max Connections is set to one by default.

Poll Interval is the next Advanced setting. It’s the frequency in seconds that clients automatically check the portal for updates. For example, if set to ten, connected clients check the portal for updates every ten seconds. The default Poll Interval is five.

Next up is the Sites tab, which lets you can control Sync on a per-site basis.

Figure 5.12: Sync Admins Sites tab lets you manage Sync on a per-site basis.

Figure 5.12: Sync Admin's Sites tab lets you manage Sync on a per-site basis.

For each site in the portal, the Sites tab lists each site’s default file permissions (more on this in a moment) and whether Sync is enabled for that site. Sync is enabled by default for all sites. To disable Sync for a site, click the drop-down arrow in the last column for the site and select Disable Sync Site. To disable multiple sites at once, select their checkboxes and click the Disable Sync Sites link that appears above the table. Please use caution when disabling Sync for a site, as doing so deletes files for that site from the Sync clients. Disabling Sync for a site, however, doesn’t affect the site’s files in the portal.

You can enable Sync for a site by selecting Enable Sync Site from its dropdown arrow. To enable Sync for multiple sites, select their checkboxes and click the Enable Sync Sites link that appears above the table.

Make sure that each site for which Sync is enabled has a Documents and Media portlet on at least one of its pages. If a site doesn’t have the portlet on any of its pages and users click the Open Website link from their Sync menus, the error message The requested resource was not found appears.

The Sites tab also lets you set default file permissions for files uploaded from Sync clients. The process for setting permissions is nearly the same as for enabling or disabling Sync for sites. To set the default file permissions for a single site, click its drop-down arrow and select Default File Permissions. This opens a window that lets you select the default file permissions for that site. Click Choose for the permissions you want to use.

Figure 5.13: Click Choose to select the default file permissions for a site in Sync.

Figure 5.13: Click *Choose* to select the default file permissions for a site in Sync.

To set the default file permissions for several sites, select the checkboxes for the sites, click the Default File Permissions link that appears above the table, and select the permissions you want to use.

Now that you know how to set default file permissions, you should learn more about what exactly they do.

Understanding Default File Permissions

The default file permissions might behave differently than you’d expect. They control only the permissions for new files uploaded through the Sync clients; they don’t affect permissions for uploading or restrict document owners (the user who originally uploaded a document) in any way. For example, even if you set a site’s default file permissions to View Only, that site’s users can still upload new documents to the site. The file’s owner has edit permission; the rest of the site’s users have the View Only permission.

Awesome! Now that you know how to configure Sync in your portal, it’s time to look closer at a use case that warrants special attention for administrators: accidental file deletion.

Protecting Against Accidental File Deletion

Liferay Sync’s power rests in its ability to propagate between the portal and connected Sync clients. When a user deletes a file from a connected client, Sync also deletes the file in the portal and in any other connected clients. Likewise, if a user deletes a file in the portal, Sync also deletes the file in all connected clients. In other words, anywhere a user deletes a file, Sync deletes it everywhere. You’re probably thinking, “This is a disaster waiting to happen!” Don’t fret! Liferay’s Recycle Bin is enabled by default and lets you recover deleted files. You can access the Recycle Bin from each site’s Site Administration menu.

Portal and site administrators can, of course, disable the Recycle Bin. Disabling the Recycle Bin in a site, however, leaves the site vulnerable to accidental file deletions that propagate through Sync.

Ensuring Sync Security

As an administrator, you’re undoubtedly concerned about the security of all connections to and from your portal. As long as your server is configured to use HTTPS, Sync clients communicate securely with your portal with user-supplied credentials. Users can only access the documents and sites they’re permitted to access. To support Security Mode in the Sync mobile client and securely transmit files, your Liferay server must also use SSL. The next section demonstrates how Sync’s permissions work with portal’s permissions.

Liferay Sync Permissions Demonstration

Sync uses Liferay’s default permissions to determine files and folders to sync with the user’s devices. It can only sync files a user can access in the portal. After installing the desktop Sync client, you can follow the steps below to test this functionality.

First, enter the text classified information into a new text file and save it on your desktop as secret.txt. Then use your browser to sign into your portal and create a new user with the user name secretagent and the email address Give this user a password and then create a new private site called Secret Site. Create a page on the site and add the Documents and Media portlet to it. Then add the secretagent user to the Secret Site and grant the Site Administrator role to the user. Log in as secretagent and select Secret Site from the My Sites menu on the Dockbar. Then upload the secret.txt document to the Documents and Media portlet. Make sure you also have a user that isn’t a member of the Secret Site and therefore doesn’t have access to any of its documents through Sync. If you don’t have such a user, create one now.

Next, configure your Liferay Sync client to sign in with the secretagent user’s credentials and sync with the Secret Site. Open the Liferay Sync menu from the system tray and select Preferences. In the Accounts tab, click the plus icon at the window’s bottom left to add an account. Provide the secretagent user’s credentials and uncheck all Liferay sites except the Secret Site. Now confirm that Sync downloaded the secret.txt file to your new Sync folder. Open it and check that it contains the text classified information. Next, use Sync to connect to your portal with the user that doesn’t belong to the Secret Site. The file doesn’t sync because this user isn’t a site member.

Now go to Sync Admin and set the Secret Site’s default file permissions to View Only. Create a new user, add them to the Secret Site, and add their account in your Liferay Sync client. As with the secretagent user, Sync downloads the secret.txt file to this user’s local Sync folder because the user is a member of the Secret Site. Now edit and save this file. Even though you can edit and save it locally, the edits aren’t synced because the site’s default file permissions are View Only. After attempting the sync, a red x appears next to the file in the local Sync folder. Right click the file to see the error. It confirms the user doesn’t have the required permissions.

Figure 5.14: The upload error occurs because the user only has permission to view files.

Figure 5.14: The upload error occurs because the user only has permission to view files.

To confirm that the error didn’t propagate through Sync, open the file in the secretagent user’s local Sync folder. It still contains the original text. Likewise, the original file remains in the site’s Documents and Media portlet. To get rid of the error in the other user’s local Sync folder, return there and then right click the file and select Download From Server. This replaces the file with the latest file in the portal.

Now edit secret.txt in the secretagent user’s local Sync folder. When you check the file in the other user’s local Sync folder and in the portal, notice that Sync propagated the edits. The changes were propagated because the secretagent user owns the file in the portal. Owners can do anything with their files, even when the site’s default file permissions are set to View Only.

Congratulations! You’ve successfully set up a Liferay Sync folder that can only be accessed by site members and administrators. You’ve also seen how Sync’s default file permissions work. By using Liferay’s permissions alongside Sync Admin’s default file permissions, Sync gives administrators two levels of control over files in their sites.

Great! Now you know how to enable and configure Liferay Sync in your portal. The next article explains how end users can install and configure the Sync desktop client.

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