http_download.sh

# http_download_curl
#
# on error: displays a message on STDERR and returns non-zero code
http_download_curl() {
  local_file=$1
  source_url=$2
  header=$3
  if [ -z "$header" ]; then
    curl -fsSL -o "$local_file" "$source_url"
  else
    curl -fsSL -H "$header" -o "$local_file" "$source_url"
  fi
}

# http_download_wget
#
# unable to get server response code in a portable manner
# busybox wget (used on alpine linux) does not support "--server-response"
#
http_download_wget() {
  local_file=$1
  source_url=$2
  header=$3
  if [ -z "$header" ]; then
    wget -q -O "$local_file" "$source_url"
  else
    wget -q --header "$header" -O "$local_file" "$source_url"
  fi
}
#
# http_download [local-file] [url] [optional extra header]
#
# if arg3 is not empty it will add it as an extra HTTP header
# must be in the form "foo: bar"
#
http_download() {
  log_debug "http_download $2"
  if is_command curl; then
    http_download_curl "$@"
    return
  elif is_command wget; then
    http_download_wget "$@"
    return
  fi
  log_crit "http_download unable to find wget or curl"
  return 1
}

# http_copy - copies contents of a URL to stdout or fail
#
# needed since curl is broken
#
http_copy() {
  tmp=$(mktemp)
  http_download "${tmp}" "$1" "$2" || return 1
  body=$(cat "$tmp")
  rm -f "${tmp}"
  echo "$body"
}