Pre and Post Requisites allow you to check particular conditions before and/or after the patch process.
Prerequisites allow you to perform checks before the patch process starts.
Postrequisites allow you to perform checks after the patch process has completed.
This allows you to check certain things like is a particular file installed? Is a particular registry entry available? Is a particular version of the VC++ Runtime installed? And you can then choose to perform actions if these conditions are rendered true.
To add/edit/delete a prerequisite, just load the list up in the patch builder and select a choice. In this documentation, we will cover the possible conditions and actions you can have.
Here is a list of conditions you can check against. Here is the syntax for them and a description of what they do. You put these in the ‘Condition Check’ box of the Edit Requisite dialog.
Condition – Check Reg File Exists
This allows you to check if a file is found on the user’s computer, specifying the directory via a registry entry.
To use this conditional check, just type in the Condition Check Box: Check Reg File Exists
Then you need to specify (in this exact order) the commands, separating each one with a colon : for the conditions and a pipe | to separate the conditions from the actions. We will provide an example below.
0/1 – 64-bit Registry Key
Registry Root – The root key of the registry
Registry Path – The path inside the root of the registry
Registry String – The String inside the path and root of the registry
Filename – the executable filename to look for
Command line Switches – Use command line switches here
Here is an example showing you how we want to check for a file on the user’s computer called myapp.exe and the patch system can use the InstallDir key inside the registry to find it. The key is a 64-bit registry key and is located under HKEY_CURRENT_USER and a path SOFTWARE\ByteBox Media\Test EXE and inside there, a string called InstallDir which is a string we setup inside our initial installer to log where the user installed to.
Check Reg File Exists:1:HKEY_CURRENT_USER:SOFTWARE\ByteBox Media\Test EXE:InstallDir:myapp.exe