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lix/scripts/nix-prefetch-url.in
Eelco Dolstra d4ca5c3952 * Use the regular progress bar; the hash bar isn't very useful when
the size of the download isn't known in advance.
2009-02-27 13:55:11 +00:00

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#! @shell@ -e
url=$1
expHash=$2
# needed to make it work on NixOS
export PATH=$PATH:@coreutils@
hashType=$NIX_HASH_ALGO
if test -z "$hashType"; then
hashType=sha256
fi
hashFormat=
if test "$hashType" != "md5"; then
hashFormat=--base32
fi
if test -z "$url"; then
echo "syntax: nix-prefetch-url URL [EXPECTED-HASH]" >&2
exit 1
fi
name=$(basename "$url")
if test -z "$name"; then echo "invalid url"; exit 1; fi
# If the hash was given, a file with that hash may already be in the
# store.
if test -n "$expHash"; then
finalPath=$(@bindir@/nix-store --print-fixed-path "$hashType" "$expHash" "$name")
if ! @bindir@/nix-store --check-validity "$finalPath" 2> /dev/null; then
finalPath=
fi
hash=$expHash
fi
mkTempDir() {
if test -n "$tmpPath"; then return; fi
local i=0
while true; do
if test -z "$TMPDIR"; then TMPDIR=/tmp; fi
tmpPath=$TMPDIR/nix-prefetch-url-$$-$i
if mkdir "$tmpPath"; then break; fi
# !!! to bad we can't check for ENOENT in mkdir, so this check
# is slightly racy (it bombs out if somebody just removed
# $tmpPath...).
if ! test -e "$tmpPath"; then exit 1; fi
i=$((i + 1))
done
trap removeTempDir EXIT SIGINT SIGQUIT
}
removeTempDir() {
if test -n "$tmpPath"; then
rm -rf "$tmpPath" || true
fi
}
doDownload() {
@curl@ $cacheFlags --fail --location --max-redirs 20 --disable-epsv \
--cookie-jar $tmpPath/cookies "$url" -o $tmpFile
}
# Hack to support the mirror:// scheme from Nixpkgs.
if test "${url:0:9}" = "mirror://"; then
if test -z "$NIXPKGS_ALL"; then
echo "Resolving mirror:// URLs requires Nixpkgs. Please point \$NIXPKGS_ALL at a Nixpkgs tree." >&2
exit 1
fi
mkTempDir
nix-build "$NIXPKGS_ALL" -A resolveMirrorURLs --argstr url "$url" -o $tmpPath/urls > /dev/null
expanded=($(cat $tmpPath/urls))
if test "${#expanded[*]}" = 0; then
echo "$0: cannot resolve $url." >&2
exit 1
fi
echo "$url expands to ${expanded[*]} (using ${expanded[0]})" >&2
url="${expanded[0]}"
fi
# If we don't know the hash or a file with that hash doesn't exist,
# download the file and add it to the store.
if test -z "$finalPath"; then
mkTempDir
tmpFile=$tmpPath/$name
# Optionally do timestamp-based caching of the download.
# Actually, the only thing that we cache in $NIX_DOWNLOAD_CACHE is
# the hash and the timestamp of the file at $url. The caching of
# the file *contents* is done in Nix store, where it can be
# garbage-collected independently.
if test -n "$NIX_DOWNLOAD_CACHE"; then
echo -n "$url" > $tmpPath/url
urlHash=$(@bindir@/nix-hash --type sha256 --base32 --flat $tmpPath/url)
echo "$url" > "$NIX_DOWNLOAD_CACHE/$urlHash.url"
cachedHashFN="$NIX_DOWNLOAD_CACHE/$urlHash.$hashType"
cachedTimestampFN="$NIX_DOWNLOAD_CACHE/$urlHash.stamp"
cacheFlags="--remote-time"
if test -e "$cachedTimestampFN" -a -e "$cachedHashFN"; then
# Only download the file if it is newer than the cached version.
cacheFlags="$cacheFlags --time-cond $cachedTimestampFN"
fi
fi
# Perform the download.
doDownload
if test -n "$NIX_DOWNLOAD_CACHE" -a ! -e $tmpFile; then
# Curl didn't create $tmpFile, so apparently there's no newer
# file on the server.
hash=$(cat $cachedHashFN)
finalPath=$(@bindir@/nix-store --print-fixed-path "$hashType" "$hash" "$name")
if ! @bindir@/nix-store --check-validity "$finalPath" 2> /dev/null; then
echo "cached contents of \`$url' disappeared, redownloading..." >&2
finalPath=
cacheFlags="--remote-time"
doDownload
fi
fi
if test -z "$finalPath"; then
# Compute the hash.
hash=$(@bindir@/nix-hash --type "$hashType" $hashFormat --flat $tmpFile)
if ! test -n "$QUIET"; then echo "hash is $hash" >&2; fi
if test -n "$NIX_DOWNLOAD_CACHE"; then
echo $hash > $cachedHashFN
touch -r $tmpFile $cachedTimestampFN
fi
# Add the downloaded file to the Nix store.
finalPath=$(@bindir@/nix-store --add-fixed "$hashType" $tmpFile)
if test -n "$expHash" -a "$expHash" != "$hash"; then
echo "hash mismatch for URL \`$url'" >&2
exit 1
fi
fi
fi
if ! test -n "$QUIET"; then echo "path is $finalPath" >&2; fi
echo $hash
if test -n "$PRINT_PATH"; then
echo $finalPath
fi