asn1dump

#!/usr/bin/env bash

# asn1dump: a convenience wrapper for `openssl asn1parse`

set -eo pipefail

function asn1parse {
  # macOS's default OpenSSL is obnoxiously old and often fails to fully decode
  # X.509v3 extensions, so we try to use Homebrew's, if available.
  if [[ "$(uname)" = "Darwin" && -n "$(command -v brew)" ]]; then
    "$(brew --prefix openssl)/bin/openssl" asn1parse "${@}"
  else
    openssl asn1parse "${@}"
  fi
}

input="${1}"
if [[ -z "${input}" ]]; then
  2>&1 echo "Usage: asn1dump <input>"
fi

suffix="${input##*.}"
suffix="${suffix,,}"
if [[ "${suffix}" = "der" ]]; then
  inform="DER"
elif [[ "${suffix}" = "pem" ]]; then
  inform="PEM"
else
  2>&1 echo "Barf: expected filename ending in .der or .pem"
  exit 1
fi

asn1parse -in "${input}" -inform "${inform}" -dump