New abortDownload function for downloadFile (#4157)

[MohabCodeX]

Warning

This feature has not been fully tested. Please test thoroughly and report any issues or unexpected behaviors. Your feedback is highly appreciated.

Sorry if I may have disappointed you, but this will take time and will need a different solution 🫠

New Functionality

• abortDownload(handlerId)
  Cancels an ongoing download using a unique handler ID.

The function returns false in these cases:

• Invalid handler ID (download doesn't exist)
• Download already completed
• Download already cancelled
• HTTP cancellation failed
• It returns true when the download was successfully cancelled.

Usage Example

local download, handlerId = downloadFile("file.txt")
-- ... later ...
local success = abortDownload(handlerId)

🛠️ Changes

• Added download tracking using unique handler IDs.
• Integrated proper cancellation logic with the HTTP manager.
• Implemented input validation for both downloadFile and abortDownload.
• memory safety and error handling throughout.

Breaking Changes

• downloadFile() now returns two values (download object, handler ID) instead of a single boolean.

🔗 Resolves

• Issue a function to abort downloads initiated with downloadFile #4157

[Fernando-A-Rocha]

I think new feature PRs are on-hold for now. 1.7 release is waiting for fixes first

Either way, this is cool

[ffsPLASMA]

Thank you for adding this feature, much needed.
If it isnt too much work, could you also add something like:

local numBytesDownloaded, numTotalBytesToDownload = getDownloadProgress(downloadHandler);

Very good addition for UIs to display the download progress.

[MohabCodeX]

The main problem is that practical usage is limited due to a fundamental issue with downloadFile.
Currently, downloadFile is blocking (synchronous), it halts script execution until the file is fully downloaded.
This prevents proper asynchronous handling and makes progress tracking ineffective during the actual download.

[ffsPLASMA]

How feasible would it be to create something like asyncDownloadFile function?

[Fernando-A-Rocha]

How feasible would it be to create something like asyncDownloadFile function?

Why not just make downloadFile not blocking? I think that wouldn't break scripts. It returns true if file to download was queued successfully - is this the slow operation?

[ffsPLASMA]

How feasible would it be to create something like asyncDownloadFile function?

Why not just make downloadFile not blocking? I think that wouldn't break scripts. It returns true if file to download was queued successfully - is this the slow operation?

Yes I see no problem making downloadFile async in general. No one sane would put lua logic after downloadFile call.