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/*!
    \example online
    \ingroup qtifwexamples
    \title Online Installer Example

    \brief Using the repogen tool and the configuration file to set up an
    online installer.

    \image qtifw-examples-online.png

    \e{Online Installer} illustrates how to set up an online installer that
    fetches the original packages and updates to them from a server.

    \include installerfw-examples-configuring.qdocinc

    \list
        \li The \c <RemoteRepositories> element is specific to an online
            installer. It can contain one or several \c <Repository> child
            elements that specify a connection to an online repository. For more
            information about the available options, see
            \l{Configuring Repositories}.
    \endlist

    \quotefile online/config/config.xml

    \include installerfw-examples-packaging.qdocinc

    \list
        \li The \c <Default> element is set to \c true to preselect the
            component in the installer.
    \endlist

    \quotefile online/packages/A/meta/package.xml

    This installer contains two components, A and B, that each have their own
    package information file with slightly different contents.

    \section1 Generating the Online Repository

    The packages need to be converted to a file structure that the installer can
    fetch at runtime. To use the \c repogen tool to convert the packages, switch
    to the example source directory on the command line and enter the following
    command:

    \list
        \li On Windows:
            \code
            ..\..\bin\repogen.exe -p packages repository
            \endcode
        \li On Linux or macOS:
            \code
            ../../bin/repogen -p packages repository
            \endcode
    \endlist

    The generated \c repository directory will now contain a full copy of the
    package data and some additionally generated metadata, such as SHA
    checksums.

    The directory now needs to be made available at the URL set in
    \c config.xml: \c{http://localhost/repository}. How this is done depends on
    the platform and web server used. If you do not have a running web server
    yet, but have Python available, you should be able to start a minimal web
    server from the command line. Make sure you are in the example directory,
    and then enter:

    \code
        python -m SimpleHTTPServer 80
    \endcode

    You should now be able to open and explore \l{http://localhost/repository}
    in your web browser.

    \note If you do not have enough permissions to set up a web server locally,
    you can also specify an absolute \c{file:///} URL as the value of the \c URL
    element in \c config.xml. For example,
    \c file:///C:/Qt/QtIFW/examples/online/repository would be a valid URL on
    Windows if \c repository is located in \c C:\Qt\QtIFW\examples\online.

    \section1 Generating the Example Installer

    To create the example installer, switch to the example source directory on
    the command line and enter the following command:

    \list
        \li On Windows:
            \code
            ..\..\bin\binarycreator.exe --online-only -c config\config.xml -p packages installer.exe
            \endcode
        \li On Linux or macOS:
            \code
            ../../bin/binarycreator --online-only -c config/config.xml -p packages installer
            \endcode
    \endlist

    You should now be able to run the installer and install from the repository.

    \section1 Providing Updates

    A benefit of using an online installer is that you can add new packages over
    time or update the existing ones. During new installations, the new and
    updated packages are automatically used, and existing installations can be
    upgraded to use them.

    To update a package, you need to increase its \c <Version> element in
    \c package.xml. The \c packages_update directory in the example folder is
    a copy of \c the package directory, with an updated component
    A. To deploy an update, you again use \c{repogen}:

    \list
        \li On Windows:
            \code
            ..\..\bin\repogen.exe --update-new-components -p packages_update repository
            \endcode
        \li On Linux or macOS:
            \code
            ../../bin/repogen --update-new-components -p packages_update repository
            \endcode
    \endlist

    \c {--update-new-components} lets \c {repogen} compare the version
    numbers of components in the repository and the packages directory, and
    only updates packages that are new, or have a higher version number.
    See also the \l{Summary of repogen Parameters}.

    If you then run the maintenance tool from the previous installation and
    select \gui {Update Components}, you should see that an update of package
    \c A is available.

    For more information on providing updates, see \l {Promoting Updates}.

    \image qtifw-examples-online-1.png
*/
