File: fetch.sh
   1 #!/bin/sh
   2 
   3 # The MIT License (MIT)
   4 #
   5 # Copyright (c) 2026 pacman64
   6 #
   7 # Permission is hereby granted, free of charge, to any person obtaining a copy
   8 # of this software and associated documentation files (the "Software"), to deal
   9 # in the Software without restriction, including without limitation the rights
  10 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11 # copies of the Software, and to permit persons to whom the Software is
  12 # furnished to do so, subject to the following conditions:
  13 #
  14 # The above copyright notice and this permission notice shall be included in
  15 # all copies or substantial portions of the Software.
  16 #
  17 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23 # SOFTWARE.
  24 
  25 
  26 # fetch [options...] [URIs/data-URIs...]
  27 #
  28 # Fetch/web-request all URIs given, using protcol HTTPS when none is given.
  29 # Base64-encoded data-URI are also supported, being simply decoded into the
  30 # bytes they represent, no loading/fetching required.
  31 #
  32 # The options are, available both in single and double-dash versions
  33 #
  34 #   -h, -help    show this help message
  35 
  36 
  37 # This version is compatible with busybox/alpine-linux.
  38 
  39 # fail quits the script right after showing the message given, using the
  40 # exit code given as its 2nd arg
  41 fail() {
  42     if [ "$2" = 23 ] || [ "$2" = 141 ]; then
  43         exit 0
  44     fi
  45     printf "%s\n" "$1" >&2
  46     exit "${2:-1}"
  47 }
  48 
  49 
  50 case "$1" in
  51     -h|--h|-help|--help)
  52         awk '/^# +fetch /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  53         exit 0
  54     ;;
  55 
  56     -) ;;
  57 
  58     --) shift ;;
  59 
  60     -*)
  61         printf "unsupported option '%s'\n" "$1" >&2
  62         exit 1
  63     ;;
  64 esac
  65 
  66 if [ $# -eq 0 ]; then
  67     awk '/^# +fetch /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  68     exit 0
  69 fi
  70 
  71 dashes=0
  72 for uri in "$@"; do
  73     if [ "${uri}" = '-' ]; then
  74         dashes="$(("${dashes}" + 1))"
  75     fi
  76 done
  77 
  78 if [ "${dashes}" -gt 1 ]; then
  79     printf "can't use dash (standard input) more than once\n" >&2
  80     exit 1
  81 fi
  82 
  83 trap 'exit 0' PIPE
  84 
  85 for uri in "$@"; do
  86     case "${uri}" in
  87         -) cat;;
  88 
  89         file://*)
  90             cat "$(echo "${uri}" | sed 's-^file://--')" ||
  91                 fail "failed to fetch ${uri}" $?
  92         ;;
  93 
  94         https://*|http://*|ftp://*|ftps://*|sftp://*|dict://*)
  95             curl -s -L "${uri}" || fail "failed to fetch ${uri}" $?
  96         ;;
  97 
  98         data:,) continue;;
  99         data:*)
 100             {
 101                 echo "${uri}" | sed -E 's-^data:.{0,50};base64,--' | base64 -d
 102             } || fail "failed to decode base64 payload from data URI" $?
 103         ;;
 104 
 105         *)
 106             if [ -e "${uri}" ]; then
 107                 cat "${uri}" || fail "failed to fetch ${uri}" $?
 108                 continue
 109             fi
 110 
 111             uri="https://${uri}"
 112             curl -s -L "${uri}" || fail "failed to fetch ${uri}" $?
 113         ;;
 114     esac
 115 done