The Application Installer
After applications have been packaged by the
application-packager, they can be installed by the application-manager at runtime. There are two interfaces for this functionality:
- a QML interface which can be used within the application-manager process, and
- a D-Bus interface which can be used by any process which is allowed to talk to the application-manager's
Both interfaces are very similar and both are documented in the ApplicationInstaller.
Note: A prerequisite for dynamically installed application packages is a valid installation location configuration for the application-manager.
When triggering a package installation, you have to provide a URL to the application-manager as the source of the package. Out of the box, the application-manager accepts the following schemes:
|A local filesystem path.|
|A remote path that will be downloaded via QNetworkAccessManager.|
|A path to a UNIX-domain socket in the local filesystem. This is very useful for streaming in packages, if you do not want to (or can) use the built-in downloader, or if your packages are wrapped inside another customer specific distribution file format.|
All of the above methods work asynchronously and also support streaming: this means that the actual installation is done while the package is being downloaded. If the package is successfully verified after the download, it only needs a quick finalization step. Otherwise, if an error occurred, the installation process is simply cancelled and rolled back.
If you want to make use of signed packages, you need to setup a public key infrastructure (PKI) to support this. You need:
- A Developer CA which is responsible for creating certicates that are distributed to developers in P12 format. The developers use these certificates to developer-sign their packages (using the Packager tool), before submitting to an app-store.
- An App-Store CA which is responsible for creating certificates that are used by app-store server backends to store-sign packages, before they are downloaded and installed onto devices.
Both these CAs can be the same, or they can be derived from a common root-CA.
As for the device, you need to install one or both of these CA-certificates (plus any root and intermediary ones), depending on the type of package you want the user to be able to install. Which CA-certificates are loaded is specified via the config file.
The application-manager sources contain a script that sets up such a PKI for the internal unit-tests: it can be found in
tests/data/certificates/create-test-certificates.sh. You should never use this to create a production environment, but it could be helpful to quickly and easily switch to developing with signed packages.
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