Only filter specific media

[ilhamsyahids]

⭐️ Feature description

Add support for filtering specific media types so the bot only processes selected content types, such as photos, videos, documents, or audio.
This would help when a source contains mixed media and we want to save only a subset instead of everything. Ideally, the filter should apply before processing begins, so non-matching media is skipped cleanly.

Example use cases include saving only images from a chat, only videos from a parsed link, or only documents from a batch task.

[Bitm-m]

Each file has its own link—even files inside a media group. You can just copy the link for whichever file you want to download. I think media groups are already pretty good. I’d just like a way to save the whole media group together while keeping all the related information

[ilhamsyahids]

Yes, I agree that individual file links already cover manual selection well.

What I’m proposing is an optional pre-filter for multi-user setups, where users may submit many kinds of links but the operator only wants specific media types, such as audio or video, to be processed. In other words, the goal is to filter before download/transfer, not manually choose files afterward.

I currently have a simple implementation using audio_video_only, and it works well. I believe we can make it more general by adding something like allowed_media_types option supporting values like audio, video, image, and document.

It would remain fully backward compatible, if unset, the bot will allowed all the files.

If this approach sounds reasonable, I can open a PR for it @krau. Thanks!

[krau]

Good idea, but I'd prefer if it wasn't too intrusive to the existing code (after all, the current functions for collecting file information are scattered all over the place). That being said, PRs are always welcome if you're up for it!