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I have a torrent that contains many files in it, but I don't want to download all of them because I need only few files among them. I am not downloading from a torrent client, but I am actually using put.io service that converts torrents into direct downloads for me.

I want to edit the .torrent file (or magnet link) in such a way that I get only those files which I need from the torrent. I tried by editing with text editors, but I am getting some crazy hash errors when I did that.

I have seen people editing trackers in a torrent file (using online editors and other editors), but none of them edited the list of files in the torrent file.

So, the question is:

How to edit a .torrent file (and save it back as another .torrent file) such that when you run that torrent file, it only downloads only those files you need?

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migrated from webapps.stackexchange.com Oct 4 '12 at 9:25

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2  
Why don't you download it through a torrent client which let you choose which file you want to download and which you don't want to. –  avirk Oct 4 '12 at 11:15
    
Can't be done. Plus I just read this on the put.io site: "When we download torrents for you, we seed every torrent until its ratio is 1:1.15." So it seems they're doing the right thing and seeding to >1:1, whereas your suggestion would ensure that they never seed the entire torrent (most likely leading to it eventually dying). If you don't want all the files, do it yourself by using a proper client as suggested above, instead of trying to get past put.io's restrictions (especially if you're using their free 1 GB account). –  Karan Oct 4 '12 at 18:45
    
I should have mentioned this before, but I am under a proxy that doesn't let me use a torrent client. Otherwise, who doesn't know about torrent clients these days? –  Forbidden Overseer Oct 22 '12 at 12:18
    
@Karan: They may not seed the entire torrent, but could just seed the part which I have downloaded to the same ratio. Doesn't that seem legit? –  Forbidden Overseer Oct 22 '12 at 12:21
    
As I mentioned above, if people don't seed entire torrents, they (the torrents, of course!) will eventually die due to lack of seeds. If that's put.io's chosen business models (making sure they seed full torrents to 1.15 ratio), I think it's a great idea. –  Karan Oct 22 '12 at 13:58

2 Answers 2

up vote 3 down vote accepted

It may not be possible - from some preliminary googling

"The torrent file format makes adding or removing files impossible without access to the original files. " from Faq - Torrent Editor

This might need client support to only download the needed files, however put.io doesnt seem to support it yet

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2  
The statement doesn't look completely true; it's certainly possible to edit the .torrent file (which is just a list of filenames+sizes+hashes+other stuff) - the problem is that editing the list will change the torrent's "infohash" regardless of whether you have the original files or not, and you won't be able to download from peers who only have the old .torrent file. –  grawity Oct 4 '12 at 13:00
    
@grawity: Yeah, but now the question is whether we can change the infohash without having those files with us? If we can generate a hash only for those files we selected, our job is pretty much done. Does the infohash work that way? Can we do that is the real question... –  Forbidden Overseer Oct 22 '12 at 12:24
    
@KarthikT: Yeah, put.io doesn't support it. But my question was more about the torrent files we upload to put.io rather than their service in the first place. Thanks for that link BTW, it's nice to know that a feature like that's gonna come up in services like put.io. Now, it's clear that put.io is having this feature in their mind despite having 1:1.15 rule like Karan said. I think they will either seed only those files we download or they would seed the complete torrent regardless of what we download in this scenario. –  Forbidden Overseer Oct 22 '12 at 12:28
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@ForbiddenOverseer: The .torrent file format is not magic. It's just a "Bencode" format structure, similar to JSON or XML, just more strictly formatted and less human-readable. You can convert it to JSON, edit it (e.g. to remove a file or to merge two .torrent files), convert to Bencode again, and it'll work. It is not the problem I'm talking about. –  grawity Oct 22 '12 at 14:57

Use BEncode Editor which can edit torrents and their file lists.

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