[facebook] add support

[zWolfrost]

Fixes #470 and #2612 (probably duplicate)
For now it supports Account Photos & Photo Albums.
The only way it can work is by making one request per post, so it's not really optimized unfortunately.
Further testing is needed.

[zWolfrost]

It looks like Facebook blocks your account for about one hour when running the extractor for too many images.
It happened to me, after running the extractor and downloading 1800 of them.
Also, it only appears to be an account ban (logging out removes the block), and it only prevents you from viewing images by opening them from a link (opening them using the react UI works).
It's probably best if the extractor actively avoids using the imported cookies, unless requested otherwise (with proper warnings).
Please let me know your thoughts.

[MrJmpl3]

It's probably best if the extractor actively avoids using the imported cookies, unless requested otherwise (with proper warnings).

I think photos and videos have a signature in the url, Facebook maybe can track you and ban using this info.

[zWolfrost]

I think photos and videos have a signature in the url, Facebook maybe can track you and ban using this info.

I don't think i understand how you would be able to ban someone using a signature in the photo url. I think the most reasonable option would just be to use the request cookies (which include your account ids and such) to account-ban you.

As i mentioned, it's not really a complete ban, it's only limited to some parts of the UI, and logging out (thus not sending the account request cookies) does remove the block, with the tradeoff that you can't view private or R-18 images.

I still don't know if being logged out in advance prevents the ban altogether. If that's the case then i think i will add a warning about that.

[zWolfrost]

After doing some more testing i can tell that not using cookies still gets you blocked from viewing images, in the sense that you are forced to log in, and it happens much faster than when using them.
I think it's best not to use cookies unless facebook forces the user to login, and print a small warning whenever the extractor uses them. Doing this i could extract about 2400 images before getting temporarily blocked, and i think that's pretty good.

Also, I'd love to know if the extractor works for anyone else other than me, so please feel free to let me know.

[AdBlocker69]

Hi, I've tested your version and it seems to be working fine for pictures. I'm planning to save quite a few images from a public Facebook page and was wondering if using one of the --sleep commands could circumvent you from being blocked (or if Facebook just reacts to an arbitrary number of request, no matter the frequency). And just overall - does that mean I'm generally unable to connect to the Facebook services (like using gallery-dl with it) or does it just prevent browser/account interaction?
Let me not forget - thanks for your work. I hope this gets implemented in the official project soon. Facebook is (still) such a big platform; so having a tool like gallery-dl supporting it is pretty important (imo)...

Facebook video support would be nice too: Luckily in my case they weren't that many so I was able to download them one by one with yt-dlp... ...But they also don't support Album/Account video downloading (yet) like they do with YouTube for example.

[zWolfrost]

Hi, thank you for your feedback.

I'm not sure if waiting to continue extracting would work, and if it did work, i have no idea for how long or after how many images the wait should start. That would require a lot of testing and unfortunately every time i get blocked i have to wait about 6 hours to try again.

To be more specific, the "block" which I'm talking about only prevents you from accessing images by their URL (the way the extractor does it), but you can still access them by using the React user interface.
That means, accessing them by clicking them, scrolling with the arrows etc., but if, for example, you reload the page while viewing one, an error pops up about you "using this feature too fast".
When not using an account, instead, you don't get the error but you get redirected to the login page (aside from that the behavior is the same though).

As far as i can tell this block is only limited to this and you can do any other thing on Facebook

About the video support, i will keep that in mind. I'm not sure how yt-dlp downloads them and i will check that out when i have time.

[AdBlocker69]

Thanks for the info :)
Btw, do you know what to do when let's say, you have downloaded 2400 pictures and get blocked afterwards, and want to continue downloading from the same profile; can you just continue after the 6 hours because I guess when checking for duplicates gallery-dl still does requests for the 2400 images (as it goes chronologically from newest to oldest post) or does that work differently?

[zWolfrost]

No, I'm sorry, once you get blocked the photo page doesn't load at all (assuming you're loading it by its URL) so there is no way to know the metadata and stuff. This is the reason why I just added a way to continue the extraction from an image in the set/album instead of having to start from the beginning. Just take the photo URL and add "&setextract" to it to download the whole set from there instead of the photo alone. The user will be prompted with this URL if they get blocked while extracting

[AdBlocker69]

Good idea for implementing that 👍🏻 Does it only work with the prompted URL because I just tried it up front by using an image link and adding "&setextract" to it but it gave me an 'unknown command' error after downloading just the singular image?

Also, it seems like your video extraction only pulls the version without audio (the best one in the list of formats in yt-dlp but it gets merged with an audio-only version there by default)... So it would be best to either add the ffmpeg merge-by-default or have it select the "hd" format by default which has video+audio.

[zWolfrost]

The "&setextract" feature didn't work to you because you probably passed it to gallery-dl without using the double quotes (") and the command prompt recognized the "&" as the split character between two commands (you can use the ampersand to execute two commands in one line). That would also explain why it downloaded the image, and then gave you an "unknown command" message, as you probably don't have a command assigned to the "setextract" keyword

By the way, after further inspection, I don't think there's a way to make an "all profile videos" extractor, as they don't share a set id i can use to navigate though them all.

Good catch for the audio thing though, i wasn't wearing headphones :)
I have fixed it right now, the audio gets downloaded as well. By default they will be separate, to merge the two you'll have to let youtube-dl/yt-dlp handle the download, by adding "videos": "ytdl" in the facebook extractor configuration

[AdBlocker69]

Okay, several things I just realized by doing some trial and error 😅:
First of all, I need to use the full link for gallery-dl to detect what "set" I even want to continue downloading from; I had just used the short version (as marked blue) and wondered why it didn't do anything anymore after downloading the image the link directs to.

Secondly, I need to then put the full link into quotation marks since it otherwise, as you said, detects the text after the ampersand as a secondary command (as marked red), giving me a 'syntax error' and not processing the rest further after downloading the image the link directs to.

So this is how it's to be written to avoid any errors due to the link format and command logic etc.

Now I got it to work successfully 👌🏻

Alternatively you can also just add the set id given to you by the previous downloading as it is in the folder name where your set images were saved to (e.g. the 'Timeline photos' set (all account images)) manually after the 'short' image link with the addition of "&set=" in front of it:

[zWolfrost]

I'm sorry if things got confusing 😥 at least you managed to make it work now.
Of course, someone who would've had their download blocked would have been prompted with the full URL already so there is no chance of this happening in a real situation (at least i hope so).
I will see if there is a way to maybe get the set id by inspecting the photo page by itself (if i remember correctly there should be a default one)

[AdBlocker69]

No problem, that's just what happens when the outgoing situation is slightly different :)
I just like to use short links as sometimes, when taking them directly from browsing the web, they have some certain parameters in them (like a less than source size of an image etc.) which are undesirable. So it's more or less best practice for me to take the link as 'raw' as possible to avoid any of that.
In this case the extra information given in the link was vital though...

[zWolfrost]

There, i just had to change the matching URL pattern a little. Now it works even without including the set id. Hopefully it's the same for you. I recommend you to avoid this anyway, as Facebook acts a little weird when you navigate images without their set id. Sometimes their sequence gets changed or some images get skipped altogether. Or maybe it just works fine and i unintentionally bugfixed it some while ago, i don't know.

[AdBlocker69]

Works 🤙🏻
Thanks; I guess it's generally helpful to have it work like that too for when you maybe just have the image link from a 3rd source of whatever and want to download from that point back - and you then don't have to specifically go back to the profile page itself to find the set id.
So quality of life wise good, no question.