Files
lix/scripts
Eelco Dolstra b74d92755d download-from-binary-cache: Use HEAD requests if possible
In "nix-env -qas", we don't need the substitute info, we just need to
know if it exists.  This can be done using a HTTP HEAD request, which
saves bandwidth.

Note however that curl currently has a bug that prevents it from
reusing HTTP connections if HEAD requests return a 404:

https://sourceforge.net/tracker/?func=detail&aid=3542731&group_id=976&atid=100976

Without the patch attached to the issue, using HEAD is actually quite
a bit slower than GET.
2012-07-11 17:53:20 -04:00
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