How to keep already downloaded packages when internet disconnects (Burn / Wix)?

[alirezafatehi]

Question

Hi,

I’m using a WiX version 5 to have a web installer that downloads EXE/MSI packages from the internet/network.

One of our requirements is offline resiliency:
If the internet connection drops, it’s OK to lose the file currently being downloaded, but already downloaded files should be kept and reused when the connection comes back.

From my testing, Burn behaves like this:

When a download fails (network issue), Burn clears the package cache folder and deletes all downloaded files.

When the connection is restored and the install is retried, Burn tries to download everything again.

This often results in:
Error 0x80091007: Hash mismatch ...
Error 0x80091007: Failed to verify hash of payload ...
for the partially downloaded file.

and If I use:

Bootstrapper.Engine.Plan(LaunchAction.Layout);

the downloaded files are copied to a layout folder and are preserved — but this is not the behavior I want for normal install.

My question:
Is there a way to configure Burn so that:

Already downloaded packages in the cache are not deleted on network failure, and

Burn can retry downloading only the missing/failed package after the internet connection is restored?

Or is the only supported solution to use Layout mode for this scenario?

Any guidance would be appreciated. Thanks!

Open Source Maintenance Fee

• I (or an organization I'm a member of) pay the Open Source Maintenance Fee by sponsoring the wixtoolset project because I support the maintainers.

[robmen]

Burn really works hard to clean up after itself when something goes wrong. There are RollbackBoundaries for installation packages, so the whole transaction isn't rolledback. But nothing like that exists for caching payloads. It could maybe be an interesting feature for someone to think through all the design challenges.