little-things/ia-metadata

#!/usr/bin/env bash
if [[ $# -eq 0 || "$1" == @(--help|-h) ]]; then
	printf 'Usage: ia-metadata ITEM [CHANGE...]\n' >&2
	printf 'Reads or modifies metadata of an item or file in an item\n' >&2
	printf 'Each CHANGE consists of two or more arguments: an operation, a field, and potentially variable further arguments for the operation.\n' >&2
	printf 'The following operations are supported:\n' >&2
	printf '  append FIELD VALUE       appends a value to a list field\n' >&2
	printf '  remove FIELD VALUE       removes the first appearance of the value in a list field\n' >&2
	printf '  set FIELD VALUE          sets the field to the value; any existing value is overwritten\n' >&2
	printf '  unset FIELD              removes the field\n' >&2
	exit 1
fi

if (($# == 1)); then
	# Read
	curl --silent --show-error --user-agent 'little-things +https://gitea.arpa.li/JustAnotherArchivist/little-things' "https://archive.org/metadata/$1"
	st="$?"

	# Emit an LF terminator if stdout is a TTY
	[[ -t 1 ]] && printf '\n'

	exit "${st}"
fi

# Write
#TODO Add 'test' operations to ensure the local state matches what's in the item: https://archive.org/developers/md-write-adv.html#use-the-test-operator
target="$1"
shift
args=()
while (($#)); do
	case "$1" in
		append)
			(($# >= 3)) || { printf 'Error: expected two arguments on append\n' >&2; exit 1; }
			args+=(op add path "/$2/-" value "$3")
			shift 3
			;;
		remove)
			printf 'Error: remove is currently unsupported due to a an apparent bug on the Internet Archive side\n' >&2
			exit 1
			(($# >= 3)) || { printf 'Error: expected two arguments on remove\n' >&2; exit 1; }
			# IA extension to JSON Patch
			args+=(op remove-first path "/$2" value "$3")
			shift 3
			;;
		set)
			(($# >= 3)) || { printf 'Error: expected two arguments on set\n' >&2; exit 1; }
			args+=(op add path "/$2" value "$3")
			shift 3
			;;
		unset)
			(($# >= 2)) || { printf 'Error: expected an argument on unset\n' >&2; exit 1; }
			args+=(op remove path "/$2")
			shift 2
			;;
		*)
			printf 'Error: invalid operation %q\n' "$1" >&2
			exit 1
			;;
	esac
done

patch="$(jq --null-input --compact-output '$ARGS.positional | . as $arr | [range(0; length/2) * 2 | $arr[. : . + 2]] | reduce .[] as [$key, $value] ([]; if $key == "op" then . += [{($key): $value}] elif .[-1][$key] then if .[-1][$key] | type == "array" then .[-1][$key] += [$value] else .[-1][$key] = [.[-1][$key], $value] end else .[-1] += {($key): $value} end)' --args "${args[@]}")"

"$(cd "$(dirname "$0")"; pwd -P)/curl-ia" header --silent --show-error --user-agent 'little-things +https://gitea.arpa.li/JustAnotherArchivist/little-things' --form '-target=metadata' --form "-patch=${patch}" "https://archive.org/metadata/${target}"
st="$?"
[[ -t 1 ]] && printf '\n'
exit "${st}"