image-upload

#!/bin/bash

set -o errexit
set -o nounset
set -o pipefail

### Example: image upload bot
###
### Upload and display inline images.
###
### * shell 1
###
###     export XMPPIPE_USERNAME=...
###     export XMPPIPE_PASSWORD=...
###
###     image-upload -o <groupchat>
###     image-upload --chat -o <jid>
###
###     # to debug
###     image-upload -vvv -o <groupchat>
###     bash -x image-upload -o <groupchat>
###
### * shell 2
###
###     echo "upload::::example.png" > /tmp/image_upload/stdin
###

trap cleanup 0

TMPDIR="${TMPDIR-/tmp/image_upload}"
mkdir "$TMPDIR"

in="$TMPDIR/stdin"
out="$TMPDIR/stdout"

mkfifo "$in"
mkfifo "$out"

cleanup() {
  rm -rf "$TMPDIR"
}

encode() {
  local string="${1}"
  local strlen=${#string}
  local encoded=""

  for ((pos = 0; pos < strlen; pos++)); do
    c=${string:$pos:1}
    case "$c" in
      [@-_.~a-zA-Z0-9]) o="${c}" ;;
      *) printf -v o '%%%02X' "'$c" ;;
    esac
    encoded+="${o}"
  done
  echo "${encoded}"
}

decode() {
  printf '%b' "${1//%/\\x}"
}

bot() {
  local filename
  # shellcheck disable=SC2034
  while IFS=: read stanza _type _from _to body; do
    case "$stanza" in
      upload)
        filename="$body"
        if [ ! -f "$filename" ]; then
          echo "error: not found: $filename"
          continue
        fi
        local content_type
        local size
        local encoded

        content_type="$(file --brief --mime-type "$filename")"
        size="$(stat --format="%s" "$filename")"
        encoded="$(encode "$(basename "$filename")|$size|$content_type")"

        echo "u::::$encoded"
        ;;
      U)
        local decoded
        decoded="$(decode "$body")"

        OFS="$IFS"
        IFS="|"
        # shellcheck disable=SC2086
        set -- $decoded

        local GET
        local PUT
        GET="$1"
        PUT="$2"

        IFS="$OFS"

        curl "$PUT" --upload-file "$filename"

        echo "$GET" >/dev/stderr

        local encoded
        encoded="$(encode "$GET")"
        echo "I::::$encoded"
        ;;
      *) echo "received: $stanza $_type $_from $_to $body" 1>&2 ;;
    esac
  done <"$in"
}

cat <<EOF
in="$TMPDIR/stdin"
out="$TMPDIR/stdout"
EOF

bot >"$out" &
xmppipe --format csv "$@" <"$out" >"$in"