Unstable downloads of Large Files with PHP SCRIPT option

[jpierre]

Hi all,

I am experiencing some similar behaviour that I found navigating in the forum on several messages about downloading some "large files"

For information, before describing the behaviour, I tested on your own platform -> https://jd40.jdownloads.org/downloads/category/62-test-files-of-different-sizes and get the same odd behaviour.

The behavior is the following :
When I download a "large" file via jDownloads (for example 250 Mb), the browser behaves as if the connection is constantly dropping and reconnecting. For example, in Google Chrome the download status keeps switching to "Resume" over and over, and the progress indicator blinks instead of progressing smoothly.
Because of this, Chrome is unable to show the remaining time, and the download never appears as a continuous stream, and sometimes fails in the middle.

However, if I download the exact same file through a direct link, the download is perfectly smooth, stable, and the progress bar behaves normally (that i couldn't test on your platform but on mine)

So the issue only happens when the file is delivered through jDownloads using Send Downloads using the PHP Script, not when served directly by the server.

Has anyone experienced this kind of repeated "disconnect/reconnect"? Any ideas what could cause this?

I can take as a workaround to uncheck Send Downloads using the PHP Script but i need then to Uncheck Protect your download Directory or I get a 403 Error, which may be quite unsecure.

I checked anything about :
- User Group Setting limit --> no limit applyed, default config
- Server PHP and Configuration etc. I have checked with my hosting provider (Infomaniak) before posting here. According to them, all server‑side settings that could affect downloads (timeouts, compression, caching, etc.) appear to be correct

And a final information, it may seem that depending on the geographical origin the behaviour is not the same ...

Thanks for sharing your experience about this

Joomla 5.4.5
Jdownloads 4.1.4 Stable
MariaDb 10.11

Server Host Infomaniak

(I am absolutely not saying it's a bug or something else, just trying to understand )

Pierre

[Arno]

Hi,
thanks for the detailed report and testing.

We investigated this in depth and were able to reproduce/verify the behavior pattern:

1. Resume/range support is working correctly (`206 Partial Content` + `Content-Range`).
2. The transfer still arrives as `Transfer-Encoding: chunked` on some setups.
3. In that case, many browsers can show transferred bytes and speed, but not the total file size in the download UI.

So at this point, this is not a simple "download broken" case, but mainly an environment-dependent delivery behavior (server/proxy stack) when using PHP-based delivery for large files.

For practical use:
1. If maximum stability/UX for very large files is the priority, direct web-server delivery is usually the best option.
2. PHP-based delivery remains useful for protected/special setups, but browser progress details may differ depending on hosting behavior.
3. We will keep improving best-effort handling in jDownloads, but some transfer characteristics are ultimately controlled outside the extension.

If you want, we can provide a short host-specific checklist (Apache/proxy/CDN) to help pinpoint exactly where chunked transfer is enforced in your environment.

Incidentally, I was able to download very large files (2 GB) from the demo without any problems or interruptions.