f881f7a017
NIX_DOWNLOAD_CACHE is set, then nix-prefetch-url will store the hash and timestamp of downloaded files in the directory $NIX_DOWNLOAD_CACHE. This allows it to figure out if the file is still in the Nix store.
118 lines
3.4 KiB
Plaintext
118 lines
3.4 KiB
Plaintext
#! @shell@ -e
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url=$1
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expHash=$2
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# needed to make it work on NixOS
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export PATH=$PATH:@coreutils@
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hashType=$NIX_HASH_ALGO
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if test -z "$hashType"; then
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hashType=sha256
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fi
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hashFormat=
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if test "$hashType" != "md5"; then
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hashFormat=--base32
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fi
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if test -z "$url"; then
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echo "syntax: nix-prefetch-url URL [EXPECTED-HASH]" >&2
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exit 1
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fi
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name=$(basename "$url")
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if test -z "$name"; then echo "invalid url"; exit 1; fi
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# If the hash was given, a file with that hash may already be in the
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# store.
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if test -n "$expHash"; then
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finalPath=$(@bindir@/nix-store --print-fixed-path "$hashType" "$expHash" "$name")
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if ! @bindir@/nix-store --check-validity "$finalPath" 2> /dev/null; then
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finalPath=
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fi
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hash=$expHash
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fi
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doDownload() {
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@curl@ $cacheFlags --fail -# --show-error --location --max-redirs 20 --disable-epsv \
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--cookie-jar $tmpPath/cookies "$url" -o $tmpFile
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}
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# If we don't know the hash or a file with that hash doesn't exist,
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# download the file and add it to the store.
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if test -z "$finalPath"; then
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tmpPath=/tmp/nix-prefetch-url-$$ # !!! security?
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tmpFile=$tmpPath/$name
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mkdir $tmpPath
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# Optionally do timestamp-based caching of the download.
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# Actually, the only thing that we cache in $NIX_DOWNLOAD_CACHE is
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# the hash and the timestamp of the file at $url. The caching of
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# the file *contents* is done in Nix store, where it can be
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# garbage-collected independently.
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if test -n "$NIX_DOWNLOAD_CACHE"; then
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urlHash="$(echo -n "$url" | nix-hash --type sha256 --base32 --flat /dev/stdin)"
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echo "$url" > "$NIX_DOWNLOAD_CACHE/$urlHash.url"
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cachedHashFN="$NIX_DOWNLOAD_CACHE/$urlHash.$hashType"
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cachedTimestampFN="$NIX_DOWNLOAD_CACHE/$urlHash.stamp"
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cacheFlags="--remote-time"
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if test -e "$cachedTimestampFN" -a -e "$cachedHashFN"; then
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# Only download the file if it is newer than the cached version.
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cacheFlags="$cacheFlags --time-cond $cachedTimestampFN"
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fi
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fi
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# Perform the download.
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doDownload
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if test -n "$NIX_DOWNLOAD_CACHE" -a ! -e $tmpFile; then
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# Curl didn't create $tmpFile, so apparently there's no newer
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# file on the server.
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hash=$(cat $cachedHashFN)
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finalPath=$(@bindir@/nix-store --print-fixed-path "$hashType" "$hash" "$name")
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if ! @bindir@/nix-store --check-validity "$finalPath" 2> /dev/null; then
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echo "cached contents of \`$url' disappeared, redownloading..." >&2
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finalPath=
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cacheFlags="--remote-time"
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doDownload
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fi
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fi
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if test -z "$finalPath"; then
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# Compute the hash.
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hash=$(@bindir@/nix-hash --type "$hashType" $hashFormat --flat $tmpFile)
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if ! test -n "$QUIET"; then echo "hash is $hash" >&2; fi
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if test -n "$NIX_DOWNLOAD_CACHE"; then
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echo $hash > $cachedHashFN
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touch -r $tmpFile $cachedTimestampFN
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fi
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# Add the downloaded file to the Nix store.
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finalPath=$(@bindir@/nix-store --add-fixed "$hashType" $tmpFile)
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if test -n "$tmpPath"; then rm -rf $tmpPath || true; fi
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if test -n "$expHash" -a "$expHash" != "$hash"; then
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echo "hash mismatch for URL \`$url'" >&2
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exit 1
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fi
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fi
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fi
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if ! test -n "$QUIET"; then echo "path is $finalPath" >&2; fi
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echo $hash
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if test -n "$PRINT_PATH"; then
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echo $finalPath
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fi
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