People grabbing a seed and uploading their own images there and using the bandwidth for themselves?

Indeed, a refer check might help.  Also, if a person was seeding to <whatever>Chan, building the .php to only accept incoming files from the IP or host-mask from <whatever>Chan might also do the trick.

People running a fake seed that contains nothing but goatse.

You mean “ghosts”? Well, the way I was thinking this was gonna work was to have a .php on the seeder, and a .php on the <whatever>Chan that acts as an extension to the <whatever>Chan (Wakaba/Futallaby) board.  When a seeder tells the <whatever>Chan’s .php that they are going to seed, they will tell their IP address, and the location of their .php file used to seed.  This will need to be done anyways as the <whatever>Chan will obviously need to know the IP address of the seeders to rout users to the seeder.  Anyways, the seeder’s .php would return a file-list of all files they are sharing upon request.  I guess to take care of what you asked, the <whatever>Chans’s .php could check the file list.  It would test random files on the file list.  PHP supports the code like:

$s =implode(“”, file(“http://filezilla.sourceforge.net/misc/ip.php”));

This means you can get the file contents of another website and domain, (the above example will return your external IP address into a string $s. I guess I could make the <whatever>Chan’s .php test this using the above code, only replacing the above URL with a seeders shared file.

Latency issues? If a seed goes down, the connection there will most likely take a long time before it timeouts, making it hard to know when to try a new one.

Hm… that’s a hard one to deal with.  Before I talked about sending a JavaScript to a user who is being redirected to a seeder, and having the JavaScript redirect the user to another seeder if that first target seeder times out or doesn’t have the file.  I guess, to deal with this issue, I could make the JavaScript do the following in response to a seeder timing out:

- Open a new window
- Redirect the user to another seeder (not the new window)
- Have the newly opened window redirect to <whatever>Chan’s .php with a parameter like: whatever.php?Cmd=ReportSeedFail&SeedIP=555.555.555.555
- Have the whatever.php on the <whatever>Chan’s side send a java script in return that will try to close the newly opened window after registering that a seeder has timed out.
- Now that the <whatever>Chan has been giving a report that a seeder has timed out, it can test for it self, verify the seeder is lagging, and…. I dunno do something, like maybe not redirect as many users to that seeder, or even ignore the seeder completely.

Though your question really is hard to deal with because FireFox users probably won’t open a new window (that’s a built in function of FireFox). Though if it was a hidden frame, that would be doable. Dunno… I’ll have to think about that, like where I would put the frame, I would have to plan in advance on where the frame would go, and how exactly it would even be given to the user machine.