nix-super/scripts/nix-prefetch-url.in
2007-09-18 08:26:55 +00:00

118 lines
3.4 KiB
Text

#! @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
doDownload() {
@curl@ $cacheFlags --fail -# --location --max-redirs 20 --disable-epsv \
--cookie-jar $tmpPath/cookies "$url" -o $tmpFile
}
# If we don't know the hash or a file with that hash doesn't exist,
# download the file and add it to the store.
if test -z "$finalPath"; then
tmpPath=/tmp/nix-prefetch-url-$$ # !!! security?
tmpFile=$tmpPath/$name
mkdir $tmpPath # !!! retry if tmpPath already exists
# 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" > $tmpPath/url
urlHash=$(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" $tmpFile)
if test -n "$tmpPath"; then rm -rf $tmpPath || true; fi
if test -n "$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