Currently working on a WPF app as a side project I came upon and interesting requirement regarding installation and deployment of the application. As a result I ended with some Squirrel and NSIS knowledge I would like to share.
The client came with a specific set of requirement for the installer
- Check for .NET 4.5.2 and offer installation if not present
- Install the application for all users (Program Files)
- Install a hardware driver as part of the install process
- Create desktop and start menu shortcuts
- Create an uninstaller
- Set the application to start after boot / logon
and the update process
- a Check for updates button in the app
- automatically and installing a newer version if available
- periodically checking for updates and installing them silently when app is minimized to tray
As you may have noticed, most .NET apps nowdays use Squirrel.Windows. The problem with Squirrel is that it cannot install a hardware driver as part of the installation process and it typically install applications to the users profile. But Squirrel is a good choice for the applictaion update requirements, so we decided to combine it with a classic installer.
We came up with an idea to combine Squirrel with NSIS. We chose NSIS because it seemed reasonable. I think it is the best of bad choices. The documentation is not very good, especially when using MUI to create a GUI with some meaningful texts and branding.
The idea was to create a NSIS installer that install the hardware driver and a Squirrel app packages and make the updates work after such installation.
The final solution consisted of multiple things combined together. We added Squirrel to the build process of the app, so each build in Release created a Squirrel install package. Then we created the NSIS installer that
- Checks for .NET 4.5.2 presence (using the NsisDotNetChecker plugin)
- Copies and installs the hardware driver (using a
/sswitch for instalaltion without a GUI)
- Installs the Squirrel package by unpacking it to the install directory in Program Files (using the NsUnzip plugin)
- Set appropriate permission for the install directory (using the AccessControl plugin)
- Copies Squirrel.exe as Update.exe to the install directory
- Creates shortcuts using the Update.exe instead of the app binary
To make Squirrel work in this scenario we also had to create a
SquirrelTemp directory one level above the install directory and make it writeable.
We also had to create a custom update logic to check for new releases and restart the app with full path to correct exe file, but in the ends, it all works.