SMTP interactive tester wrapper for swaks (https://jetmore.org/john/code/swaks/)

swaksWrapper.sh

#!/usr/bin/env bash
# SMTP interactive tester wrapper for swaks
# Gioxx, 2025 - https://github.com/gioxx
# - Checks and optionally installs swaks and Net::SSLeay (interactive)
# - Prompts the user for SMTP parameters with sensible defaults (Office365)
# - Builds a safe argument vector and runs swaks
# - Appends an RFC-like date to the Subject

set -euo pipefail

# Prompt with default value
prompt_default() {
  local var_name="$1"; shift
  local prompt_msg="$1"; shift
  local default="$1"; shift
  local reply

  if [ -t 0 ]; then
    read -r -p "$prompt_msg [$default]: " reply || reply=""
  else
    reply="$default"
  fi

  if [ -z "${reply}" ]; then
    eval "$var_name=\"\$default\""
  else
    eval "$var_name=\"\$reply\""
  fi
}

# Yes/No prompt (default yes = true)
prompt_yesno() {
  local var_name="$1"; shift
  local prompt_msg="$1"; shift
  local default_yes="${1:-y}"; shift
  local reply

  if [ -t 0 ]; then
    read -r -p "$prompt_msg ($([ "$default_yes" = "y" ] && echo "Y/n" || echo "y/N")): " reply || reply=""
  else
    reply="$default_yes"
  fi

  reply="${reply,,}" # to lowercase
  if [ -z "$reply" ]; then
    reply="$default_yes"
  fi

  if [[ "$reply" == "y" || "$reply" == "yes" ]]; then
    eval "$var_name=true"
  else
    eval "$var_name=false"
  fi
}

# Root or sudo helper
need_sudo() {
  if [ "$(id -u)" -eq 0 ]; then
    echo ""
  elif command -v sudo >/dev/null 2>&1; then
    echo "sudo"
  else
    echo ""
  fi
}

# Detect basic OS / package manager
detect_pkg_env() {
  # Outputs two values: PKG_MGR and FAMILY
  # FAMILY: deb|rhel|alpine|mac|unknown
  if [ "$(uname -s)" = "Darwin" ]; then
    echo "brew mac"
    return
  fi

  if [ -f /etc/os-release ]; then
    . /etc/os-release
    ID_LIKE="${ID_LIKE:-}"
    case "$ID $ID_LIKE" in
      *debian*|*ubuntu*|*Debian*|*Ubuntu*)
        if command -v apt >/dev/null 2>&1 || command -v apt-get >/dev/null 2>&1; then
          echo "apt deb"
          return
        fi
        ;;
      *rhel*|*fedora*|*centos*|*rocky*|*almalinux*)
        if command -v dnf >/dev/null 2>&1; then
          echo "dnf rhel"; return
        elif command -v yum >/dev/null 2>&1; then
          echo "yum rhel"; return
        fi
        ;;
      *alpine*)
        if command -v apk >/dev/null 2>&1; then
          echo "apk alpine"; return
        fi
        ;;
    esac
  fi

  # Fallback unknown
  echo "unknown unknown"
}

# Install swaks
install_swaks() {
  local SUDO; SUDO="$(need_sudo)"
  local PKG_MGR FAMILY; read -r PKG_MGR FAMILY < <(detect_pkg_env)

  case "$FAMILY" in
    deb)
      $SUDO apt update
      $SUDO apt install -y swaks
      ;;
    rhel)
      if [ "$PKG_MGR" = "dnf" ]; then
        $SUDO dnf install -y swaks || $SUDO dnf install -y perl-App-cpanminus
      else
        $SUDO yum install -y swaks || $SUDO yum install -y perl-App-cpanminus
      fi
      ;;
    alpine)
      $SUDO apk add --no-cache swaks
      ;;
    mac)
      if ! command -v brew >/dev/null 2>&1; then
        echo "Homebrew not found. Install it from https://brew.sh and re-run." >&2
        return 1
      fi
      brew install swaks
      ;;
    *)
      echo "Unsupported OS for auto-install of swaks. Please install swaks manually." >&2
      return 1
      ;;
  esac
}

# Install Net::SSLeay (and IO::Socket::SSL)
install_net_ssleay() {
  local SUDO; SUDO="$(need_sudo)"
  local PKG_MGR FAMILY; read -r PKG_MGR FAMILY < <(detect_pkg_env)

  case "$FAMILY" in
    deb)
      $SUDO apt update
      $SUDO apt install -y libnet-ssleay-perl libio-socket-ssl-perl
      ;;
    rhel)
      if [ "$PKG_MGR" = "dnf" ]; then
        $SUDO dnf install -y perl-Net-SSLeay perl-IO-Socket-SSL
      else
        $SUDO yum install -y perl-Net-SSLeay perl-IO-Socket-SSL
      fi
      ;;
    alpine)
      # Package names can vary by repo; try common ones:
      $SUDO apk add --no-cache perl-net-ssleay perl-io-socket-ssl || {
        echo "Falling back to cpan for Alpine ..." >&2
        $SUDO apk add --no-cache perl make gcc g++ openssl-dev perl-dev
        cpan -T -i Net::SSLeay IO::Socket::SSL
      }
      ;;
    mac)
      if ! command -v brew >/dev/null 2>&1; then
        echo "Homebrew not found. Install it from https://brew.sh and re-run." >&2
        return 1
      fi
      # Try system Perl via CPAN (often the most reliable for these modules)
      # Ensure Perl available (macOS has one), but we also prepare cpanminus if present
      if command -v cpanm >/dev/null 2>&1; then
        cpanm --notest Net::SSLeay IO::Socket::SSL
      else
        # cpan will ask first-time config; user interaction may be required
        cpan -T -i Net::SSLeay IO::Socket::SSL
      fi
      ;;
    *)
      echo "Unsupported OS for auto-install of Net::SSLeay. Please install it manually." >&2
      return 1
      ;;
  esac
}

# Checkers
have_swaks() { command -v swaks >/dev/null 2>&1; }
have_net_ssleay() { perl -MNet::SSLeay -e 'print $Net::SSLeay::VERSION' >/dev/null 2>&1; }

if ! have_swaks; then
  echo "swaks not found."
  prompt_yesno INSTALL_SWAKS "Install swaks now?" y
  if [ "$INSTALL_SWAKS" = true ]; then
    install_swaks || { echo "Failed to install swaks." >&2; exit 2; }
  else
    echo "Cannot proceed without swaks." >&2
    exit 2
  fi
fi

# Check Net::SSLeay now; if missing and user selects TLS later, we'll re-check and offer install again.
if ! have_net_ssleay; then
  echo "Perl module Net::SSLeay not found (required for TLS)."
  prompt_yesno INSTALL_SSL "Install Net::SSLeay (and IO::Socket::SSL) now?" y
  if [ "$INSTALL_SSL" = true ]; then
    install_net_ssleay || echo "Warning: failed to install Net::SSLeay. You can still use 'None' security."
  fi
fi

echo "=== SMTP interactive swaks wrapper ==="

DEFAULT_HOST="smtp.office365.com"
DEFAULT_PORT="587"
DEFAULT_AUTH_METHOD="LOGIN"  # LOGIN, PLAIN, CRAM-MD5

prompt_default HOST "SMTP server" "$DEFAULT_HOST"
prompt_default PORT "Port" "$DEFAULT_PORT"

echo "Choose security mode:"
echo "  1) STARTTLS (recommended for port 587)"
echo "  2) SMTPS (implicit TLS, typical port 465)"
echo "  3) None (plain, dev only)"
read -r -p "Select 1,2,3 [1]: " sec_choice
sec_choice=${sec_choice:-1}
case "$sec_choice" in
  1) SECURITY="starttls" ;;
  2) SECURITY="smtps" ;;
  3) SECURITY="none" ;;
  *) SECURITY="starttls" ;;
esac

# If TLS was chosen, ensure Net::SSLeay is present (offer install if still missing)
if [[ "$SECURITY" != "none" ]] && ! have_net_ssleay; then
  echo "TLS selected but Net::SSLeay is missing."
  prompt_yesno INSTALL_SSL2 "Install Net::SSLeay (and IO::Socket::SSL) now?" y
  if [ "$INSTALL_SSL2" = true ]; then
    install_net_ssleay || { echo "Failed to install Net::SSLeay; cannot proceed with TLS." >&2; exit 3; }
  else
    echo "Cannot proceed with TLS/SMTPS without Net::SSLeay. Choose 'None' or re-run." >&2
    exit 3
  fi
fi

prompt_yesno USE_AUTH "Use SMTP authentication?" y

if [ "$USE_AUTH" = true ]; then
  read -r -p "Auth method (LOGIN/PLAIN/CRAM-MD5) [${DEFAULT_AUTH_METHOD}]: " AUTH_METHOD
  AUTH_METHOD=${AUTH_METHOD:-$DEFAULT_AUTH_METHOD}
  read -r -p "Username (user@domain): " USERNAME
  if [ -t 0 ]; then
    read -r -s -p "Password: " PASSWORD; echo
  else
    PASSWORD=""
  fi
fi

prompt_default FROM "From address" "${USERNAME:-noreply@contoso.com}"
prompt_default TO "To address" "${FROM:-your.email@contoso.com}"
prompt_default SUBJECT "Subject base text" "swaks SMTP test"

echo "Enter message body — finish with Ctrl-D on an empty line:"
BODY=$(cat)  # Ctrl-D to end; empty -> default below

DATE_STR=$(LC_TIME=C date +"%a, %d %b %Y %T %z")
FINAL_SUBJECT="${SUBJECT} ${DATE_STR}"

args=()
args+=(--to "$TO")
args+=(--from "$FROM")
args+=(--server "$HOST")
args+=(--port "$PORT")

case "$SECURITY" in
  starttls) args+=(--tls) ;;
  smtps)    args+=(--smtps) ;;
  none)     : ;;
esac

if [ "$USE_AUTH" = true ]; then
  args+=(--auth "$AUTH_METHOD")
  args+=(--auth-user "$USERNAME")
  if [ -z "${PASSWORD:-}" ] && [ -t 0 ]; then
    read -r -s -p "Password (again): " PASSWORD; echo
  fi
  args+=(--auth-password "$PASSWORD")
fi

args+=(--header "Subject: $FINAL_SUBJECT")

if [ -z "$BODY" ]; then
  BODY="Hello from swaks wrapper at $(date -u +"%Y-%m-%dT%H:%M:%SZ")"
fi
args+=(--body "$BODY")

echo
echo "=== Summary ==="
echo "Server: $HOST:$PORT"
echo "Security: $SECURITY"
if [ "$USE_AUTH" = true ]; then
  echo "Auth: yes (method: $AUTH_METHOD, user: $USERNAME)"
  echo "Password: ******** (hidden)"
else
  echo "Auth: no"
fi
echo "From: $FROM"
echo "To: $TO"
echo "Subject: $FINAL_SUBJECT"
echo "Body length: ${#BODY} bytes"
echo "================"
echo

prompt_yesno CONFIRM "Run swaks now?" y
if [ "$CONFIRM" != true ]; then
  echo "Aborted by user."
  exit 0
fi

echo "Running swaks ..."
exec swaks "${args[@]}"