Restore Mojang skins proxy about chrly

[Nik-mmzd]

we easily performed 19k requests from the one IP for about a minute (Mojang, if it affects you, we are really sorry. You know, it's all for science!)

It was pretty easy. Only 1k curl threads and about 100% CPU load :D

[afdw]

It is also possible to make new versions of patched Authlib for Minecraft 1.2.5+ that will pass special flag to Ely.by (like noMojang=true). When the server receives a request with this flag, it does not make a request to Mojang if there is no skin in Ely.by database, but instead informs the client that it has to fetch the skin from Mojang itself, using IP address of the user.

[turikhay]

@afdw it may also work as a proxy for Ely.by itself by forwarding the full response from Mojang to Ely. As far as I know all responses are signed, so Ely is able to do the validation.

[erickskrauch]

@turikhay yes, I have thought about it, but there is one key problem: we are going to receive textures, that we don't know. Ely.by codebase uses md5 to identify skins, but even with over 1 500 000 skins in our DB there will be very low hit rate of known textures. I'm not saying that it would not work, but I'd imagine that there will be a lot of skins, that'll never appear on Ely.by. Of course, we can drastically increase Ely.by's skins base, but without a skin recognition system this will only increase the memory costs without a real benefit to the project.

@afdw yeah, it sounds like a good idea. We may decrease the load by reallocating this logic into Authlib (Minecraft 1.7.10+), but for old versions (we are still keeping support for Minecraft 1.2.5) this solution could be the only possible solution, since writing patch for obfuscated classes is not a good idea.

[Nik-mmzd]

@erickskrauch we can use both solutions at once: 1.7.10+ will request Mojang textures by itself, older versions will ask chrly for Mojang textures, so it will lower Mojang textures RPS

[TheRadioGuy]

If skin is not exists in database - get skin by mojang api.

If you reached mojang api limit - add this task to queue, and return default Steve skin to client;

You can create longpoll connection, and when we will get skin, we will return skin to client;