Automatically checking for a new version of my application

Question

Trying to honor a feature request from our customers, I\'d like that my application, when Internet is available, check on our website if a new version is available.

The

Answer 1

Just put an (XML) file on your server with the version number of the latest version, and a URL to the download the new version from. Your application can then request the XML file, look if the version differs from its own, and take action accordingly.

Answer 2

If you want to keep it really basic, simply upload a version.txt to a webserver, that contains an integer version number. Download that check against the latest version.txt you downloaded and then just download the msi or setup package and run it.

More advanced versions would be to use rss, xml or similar. It would be best to use a third-party library to parse the rss and you could include information that is displayed to your user about changes if you wish to do so.

Basically you just need simple download functionality.

Both these solutions will only require you to access port 80 outgoing from the client side. This should normally not require any changes to firewalls or networking (on the client side) and you simply need to have a internet facing web server (web hosting, colocation or your own server - all would work here).

There are a couple of commercial auto-update solutions available. I'll leave the recommendations for those to others answerers, because I only have experience on the .net side with Click-Once and Updater Application Block (the latter is not continued any more).

Answer 3

I think that simple XML file on the server would be sufficient for version checking only purposes.

You would need then only an ftp account on your server and build system that is able to send a file via ftp after it has built a new version. That build system could even put installation files/zip on your website directly!

Answer 4

Martin,

you are absolutely right of course. But I would deliver the launcher with the installer. Or just download the installer, launch it and quit myself as soon as possible. The reason is bugs in the launcher. You would never, ever, want to be dependent on a component you cannot update (or forget to include in the initial drop).

So the payload I distribute with the updating process of my application is just the standard installer, but devoid of any significant UI. Once the client has checked that the installer has a chance of running successfully and once it has downloaded the updater, it runs that and quits itself.

The updater than runs, installs its payload into the original installation directory and restarts the (hopefully updated) application.

Still: The process is hairy and you better think twice before implementing an Auto Update functionality on the Windows Platform when your application has a wide focus of usage.

Answer 5

in php, the thing is easy:

<?php
    if (version_compare($_GET['version'], "1.4.0") < 0){
        echo "http://www.example.com/update.exe";
    }else{
        echo "no update";
    }
?>

if course you could extend this so the currently available version isn't hard-coded inside the script, but this is just about illustrating the point.

In your application you would have this pseudo code:

result = makeHTTPRequest("http://www.example.com/update?version=" + getExeVersion());
if result != "no update" then
    updater = downloadUpdater(result);
    ShellExecute(updater);
    ExitApplication;
end;

Feel free to extend the "protocol" by specifying something the PHP script could return to tell the client whether it's an important, mandatory update or not.

Or you can add some text to display to the user - maybe containing some information about what's changed.

Your possibilities are quite limitless.

Answer 6

The simplest way to make this happen is to fire an HTTP request using a library like libcurl and make it download an ini or xml file which contains the online version and where a new version would be available online.

After parsing the xml file you can determine if a new version is needed and download the new version with libcurl and install it.