The Updater class (in the flash.desktop package) includes one method, update(), which you can use to update the currently running application with a different version. For example, if the user has a version of the AIR file ("Sample_App_v2.air") located on the desktop, the following code updates the application.
var updater:Updater = new Updater(); var airFile:File = File.desktopDirectory.resolvePath("Sample_App_v2.air"); var version:String = "2.01"; updater.update(airFile, version);
var updater = new air.Updater(); var airFile = air.File.desktopDirectory.resolvePath("Sample_App_v2.air"); var version = "2.01"; updater.update(airFile, version);
Before an application uses the Updater class, the user or the application must download the updated version of the AIR file to the computer. For more information, see Downloading an AIR file to the user’s computer .
When an application in the runtime calls the update() method, the runtime closes the application, and it then attempts to install the new version from the AIR file. The runtime checks that the application ID and publisher ID specified in the AIR file matches the application ID and publisher ID for the application calling the update() method. (For information on the application ID and publisher ID, see AIR application descriptor files.) It also checks that the version string matches the version string passed to the update() method. If installation completes successfully, the runtime opens the new version of the application. Otherwise (if the installation cannot complete), it reopens the existing (pre-install) version of the application.
On Mac OS, to install an updated version of an application, the user must have adequate system privileges to install to the application directory. On Windows and Linux, a user must have administrative privileges.
If the updated version of the application requires an updated version of the runtime, the new runtime version is installed. To update the runtime, a user must have administrative privileges for the computer.
When testing an application using ADL, calling the update() method results in a runtime exception.
The string that is specified as the version parameter of the update() method must match the string in the version or versionNumber element in the application descriptor file for the AIR file to be installed. Specifying the version parameter is required for security reasons. By requiring the application to verify the version number in the AIR file, the application will not inadvertently install an older version. (An older version of the application might contain a security vulnerability that has been fixed in the currently installed application.) The application should also check the version string in the AIR file with version string in the installed application to prevent downgrade attacks.
Prior to AIR 2.5, the version string can be of any format. For example, it can be "2.01" or "version 2". In AIR 2.5, or later, the version string must be a sequence of up to three, three-digit numbers separated by periods. For example, “.0”, “1.0”, and “67.89.999” are all valid version numbers. You should validate the update version string before updating the application.
If an Adobe AIR application downloads an AIR file via the web, it is a good practice to have a mechanism by which the web service can notify the Adobe AIR application of the version being downloaded. The application can then use this string as the version parameter of the update() method. If the AIR file is obtained by some other means, in which the version of the AIR file is unknown, the AIR application can examine the AIR file to determine the version information. (An AIR file is a ZIP-compressed archive, and the application descriptor file is the second record in the archive.)
For details on the application descriptor file, see AIR application descriptor files.
Publishing updates in an ad-hoc manner complicates the tasks of managing multiple application versions and also makes tracking certificate expiry dates difficult. Certificates may expire before you can publish an update.
Adobe AIR runtime treats an application update published without a migration signature as a new application. Users must uninstall their current AIR application before they can install the application update.
To resolve the problem, upload each updated application with the latest certificate to a separate deployment URL. Include a mechanism that reminds you to apply migration signatures when your certificate is within the 180 days grace period. See Signing an updated version of an AIR application for more information.
See ADT commands for information on how to apply signatures.
Perform the following tasks to streamline the process of applying the migration signatures:
Upload each updated application to a separate deployment URL.
Upload the upgrade descriptor XML file and the latest certificate for the update to the same URL.
Sign the updated application with the latest certificate.
Apply a migration signature to the updated application with the certificate used to sign the previous version located at a different URL.