File: fetch.sh
   1 #!/bin/sh
   2 
   3 # The MIT License (MIT)
   4 #
   5 # Copyright © 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 only options show this help message, via any of `-h`, `--h`, `-help`,
  33 # or `--help`.
  34 
  35 
  36 # fail quits the script right after showing the message given, using
  37 # exit code given as its 2nd arg
  38 fail() {
  39     if [ "$2" = 23 ] || [ "$2" = 141 ]; then
  40         exit 0
  41     fi
  42     printf "%s\n" "$1" > /dev/stderr
  43     exit "${2:-1}"
  44 }
  45 
  46 
  47 case "$1" in
  48     -h|--h|-help|--help)
  49         awk '/^# +fetch /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  50         exit 0
  51     ;;
  52 esac
  53 
  54 [ "$1" = '--' ] && shift
  55 
  56 if [ $# -eq 0 ]; then
  57     awk '/^# +fetch /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  58     exit 0
  59 fi
  60 
  61 dashes=0
  62 for uri in "$@"; do
  63     if [ "${uri}" = '-' ]; then
  64         dashes="$(("${dashes}" + 1))"
  65     fi
  66 done
  67 
  68 if [ "${dashes}" -gt 1 ]; then
  69     printf "can't use dash (standard input) more than once\n" >&2
  70     exit 1
  71 fi
  72 
  73 command='curl -s'
  74 # command='curl --show-error -s'
  75 
  76 trap 'exit 0' PIPE
  77 
  78 for uri in "$@"; do
  79     case "${uri}" in
  80         -) cat;;
  81 
  82         data:,) continue;;
  83 
  84         file://*)
  85             cat "$(echo "${uri}" | sed 's-^file://--')" ||
  86                 fail "failed to fetch ${uri}" $?
  87         ;;
  88 
  89         https://*|http://*|ftp://*|ftps://*|sftp://*|dict://*)
  90             ${command} "${uri}" || fail "failed to fetch ${uri}" $?
  91         ;;
  92 
  93         data:*)
  94             {
  95                 echo "${uri}" | sed -E 's-^data:.{0,50};base64,--' | base64 -d
  96             } || fail "failed to decode base64 payload from data URI" $?
  97         ;;
  98 
  99         *)
 100             if [ -e "${uri}" ]; then
 101                 cat "${uri}" || fail "failed to fetch ${uri}" $?
 102                 continue
 103             fi
 104 
 105             uri="https://${uri}"
 106             ${command} "${uri}" || fail "failed to fetch ${uri}" $?
 107         ;;
 108     esac
 109 done