nixpkgs/pkgs/build-support/fetchurl/builder.sh
Eelco Dolstra 50321b735b * Basic transparent mirror support in fetchurl (NIXPKGS-70). When
fetching a file with hash HASH of type TYPE, we first try to
  download <base-url>/<type>/<hash>, where <base-url> is one of a list
  of mirrors.  For instance, given

    src = fetchurl {
      url = http://releases.mozilla.org/pub/mozilla.org/firefox/releases/2.0.0.6/source/firefox-2.0.0.6-source.tar.bz2;
      sha1 = "eb72f55e4a8bf08e8c6ef227c0ade3d068ba1082";
    };

  and the mirror list [http://nix.cs.uu.nl/dist/tarballs], we first
  try to download

    eb72f55e4a

  and if that fails, we use the original URL.

  The list of mirrors is not yet user-configurable.

* `fetchurl' now also accepts an argument `urls' instead of `url' for
  a list of alternative download locations, which fetchurl will try in
  sequence.

svn path=/nixpkgs/trunk/; revision=9190
2007-08-23 15:22:30 +00:00

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source $stdenv/setup
header "downloading file $name with $outputHashAlgo hash $outputHash..."
# Curl flags to handle redirects, not use EPSV, handle cookies for
# servers to need them during redirects, and work on SSL without a
# certificate (this isn't a security problem because we check the
# cryptographic hash of the output anyway).
curl="curl \
--location --max-redirs 20 \
--disable-epsv \
--cookie-jar cookies \
--insecure"
tryDownload() {
local url="$1"
echo
header "trying $url"
success=
if $curl --fail "$url" --output "$out"; then
success=1
fi
stopNest
}
finish() {
# On old versions of Nix, verify the hash of the output. On newer
# versions, Nix verifies the hash itself.
if test "$NIX_OUTPUT_CHECKED" != "1"; then
if test "$outputHashAlgo" != "md5"; then
echo "hashes other than md5 are unsupported in Nix <= 0.7, upgrade to Nix 0.8"
exit 1
fi
actual=$(md5sum -b "$out" | cut -c1-32)
if test "$actual" != "$id"; then
echo "hash is $actual, expected $id"
exit 1
fi
fi
stopNest
exit 0
}
for mirror in $hashedMirrors; do
url="$mirror/$outputHashAlgo/$outputHash"
if $curl --fail --silent --show-error --head "$url" \
--write-out "%{http_code}" --output /dev/null > code 2> log; then
tryDownload "$url"
if test -n "$success"; then finish; fi
else
# Be quiet about 404 errors, which we interpret as the file
# not being present on this particular mirror.
if test "$(cat code)" != 404; then
echo "error checking the existence of $url:"
cat log
fi
fi
done
success=
for url in $urls; do
tryDownload "$url"
if test -n "$success"; then finish; fi
done
echo "error: cannot download $name from any mirror"
exit 1