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delphidelphi-xe2shellexecute

Suggestions for replacing the current exe

I need to do a quick and dirty way of upgrading my application.

Currently I have an exe per every release.

If exe is wrong i flash a message "relase X found on db, you are using exe for release Y, please download the correct vetsion".

I have every exe at a fixed addresss, like: http://myip.com/exes/N/Project.exe (where N is the releease)

So my idea was instead of the message above i would prompt the user "the correct exe will be downloaded, press ok to continue".

my idea is after OK:

1) Run with ShellExecute another exe (let's call id Update.exe) that takes care of downlaod and replace (this exe could be stored in exe resources)

2) Close the application

2) Update.exe will download the correct exe from internet and save it to a temp folder

4) Update.exe will delete Project.exe and replace it with the downloaded one

5) Update.exe will run the new Project.exe

So the corret exe will be run and the user will have the new exe in the same location as the old exe. This would be a non hortodox upgrade (not using Windos update, but believe me I need this. I don't ue WIndows update).

Could you comment on this approach? Or suggest a similar trick?

Solution

  • I do this, and it works well for me:

    After OK, this is done in UpdateOKClick:

    1. Display a progress bar and use InternetReadFile to read the new version install executable and write it to a temporary file (use GetTempPath in the System unit).
    2. Display a message box stating "Download complete. Closing program to install new version."
    3. Call ShellExecute to run the new version install executable from the temporary file location. The trick is that I call the install program (I'm using Inno Setup) with two special parameters: /silent and /noicons.
    4. Run Application.Terminate to close the program.

    The program terminates immediately, and the install has a bit of a delay to it, so it starts after the program is already closed. The user will see the install progress screen that Inno Setup displays, but because of the two parameters, it will not ask any questions.

    The final step of the Inno Setup install is to launch the program. It does so calling it with a /webupdate parameter.

    When the program is launched, it checks if the webupdate parameter was used. If so, it does any initialization necessary for the new version, and then displays a message box stating "Program is now updated to Version xxx".

    There are a lot of checks and possible messages to issue along the way, including giving the user the option to cancel at any time, but that is basically it.

    ... and I don't have to delete the previous executable. It just gets overwritten. That will fail if the user has a second instance of the program open, but that's another thing to check for.