initial importshlib

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+#!/bin/sh
+# this file is licensed under any of the following SPDX licenses
+# to be chosen by the user:
+# * 0BSD (https://spdx.org/licenses/0BSD.html)
+# * BlueOak-1.0.0 (https://blueoakcouncil.org/license/1.0.0)
+# * CC0-1.0 (https://creativecommons.org/publicdomain/zero/1.0/)
+# * Unlicense (https://unlicense.org/)
+
+# this all works with toybox, busybox and coreutils
+# everything except http_src and http_run is POSIXLY correct
+# http_src and http_run are exceptions due to needing mktemp
+
+# the main issue with this is you ultimately need to fetch it too
+# because of this, http_eval, http_run and http_src are provided
+# the idea is that you copy paste this at the start of your script,
+# then use those to run your *actual* script, with all the stuff set
+# this is a bit awkward, but tends to provide the best user experience
+# as such, this file is the only code that gets duplicated
+
+# priority list for utilities, they're tried in order
+# you're not allowed to overwrite them because _fetch and _print
+# behavior is hardcoded
+
+# download speed order
+HTTP_FETCH_LIST='curl wget ht xh'
+
+# wget is a bit awkward on busybox-likes with tls
+HTTP_PRINT_LIST='curl ht xh wget'
+
+# $1: the command to check
+# returns true on null input
+hascmd() {
+	test -x "$(command -v $1)"
+}
+
+# detect http getting for downloads
+if [ -z "$HTTP_FETCH" ]; then
+	for c in $HTTP_FETCH_LIST
+	do
+		hascmd $c || continue
+		HTTP_FETCH=$c
+		break
+	done
+	echo "Using ${HTTP_FETCH:?could not find an http fetcher} for http fetching."
+fi
+
+# detect http getting for piping
+if [ -z "$HTTP_PRINT" ]; then
+	for c in $HTTP_PRINT_LIST
+	do
+		hascmd $c || continue
+		HTTP_PRINT=$c
+		break
+	done
+	echo "Using ${HTTP_PRINT:?could not find an http printer} for http piping."
+fi
+
+# for http_run
+export HTTP_FETCH HTTP_PRINT
+
+# $1 is the url
+# $2 is the destination file
+# intermediate directories are automatically handled
+http_fetch() {
+	mkdir -p "$(dirname $2)"
+
+	echo "fetch $2" >&2
+	case "$HTTP_FETCH" in
+	curl) curl -so "$2" "$1" ;;
+	ht) ht --ignore-stdin -bdo "$2" --overwrite "$1" ;;
+	wget) wget -qO "$2" "$1" ;;
+	xh) xh -Ibdo "$2" "$1" ;;
+	*) echo 'Invalid http fetching utility.' >&2; exit 1 ;;
+	esac >/dev/null
+}
+
+# $1 is the url
+http_print() {
+	case "$HTTP_PRINT" in
+	curl) curl -s "$1" ;;
+	ht) ht --ignore-stdin -b "$1" ;;
+	wget) wget -qO- "$1" ;;
+	xh) xh -Ib "$1" ;;
+	*) echo 'Invalid http printing utility.' >&2; exit 1 ;;
+	esac
+}
+
+# $1 is the url
+# prints the file to use
+http_run_src_prep() {
+	f=$(mktemp)
+	http_fetch "$1" "$f"
+	echo "$f"
+}
+
+# $1 is the url
+# args are not allowed
+# don't use this unless you know what you're doing
+http_eval() {
+	eval "$(http_print $1)"
+}
+
+# $1 is the url
+# rest are args to pass
+http_run() {
+	f="$(http_run_src_prep $1)"
+	shift
+	chmod +x "$f"
+	"$f" "$@"
+	rm "$f"
+}
+
+# $1 is the url
+# rest are args to pass
+http_src() {
+	f="$(http_run_src_prep $1)"
+	shift
+	. "$f" "$@"
+	rm "$f"
+}
+
+# print all keys in an s3 bucket
+# $1 is the bucket url
+s3_list() {
+	http_print "$1" |
+	sed 's/</\n</g' |
+	sed '/<Key>/!d;s/^<Key>//'
+}