nuget

/nuget/index.json

.NET packages, with the service index pointed back at you

Point your client at it

bash

dotnet nuget add source http://HOST:10220/nuget/index.json -n libworld

Replace HOST with your mirror’s address. Port 10220 is the server’s default.

Upstream: https://api.nuget.org
What is stored: Packages in the blob store and catalogued; registrations and the service index on local disk.

How it works

NuGet does not have fixed endpoints. It fetches one service index and discovers every other URL from it, which means a mirror that merely proxied that document would hand clients nuget.org's addresses and be bypassed on the very next request. So LibWorld SYNTHESIZES the service index, advertising its own URLs.
Registration documents get rewritten for the same reason: they carry absolute package-content URLs that would otherwise lead straight back out.
.nupkg files never change once published and are cached permanently.

Things that have cost real time

Written down because they were paid for once already.

NuGet's gz-semver2 endpoints serve gzipped JSON, and the mirror caches and serves the decompressed body. Storing the compressed bytes would mean re-serving an encoding the client never asked for.

Only the flat-container per-version files are immutable — the .nupkg and its .nuspec. The service index, the version list, and the registration pages all change as versions appear, so all three are revalidated.