From 1de9ffacb0e38a6a26291b088645638d0a3a890c Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Tue, 29 Dec 2020 16:28:38 -0800
Subject: [PATCH 01/17] Implement smtp notify hook

Support notifications via direct SMTP server connection.
Uses Python (2.7.x or 3.4+) to communicate with SMTP server.
---
 notify/smtp.sh | 185 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 183 insertions(+), 2 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index 6aa37ca3..367021c8 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -2,7 +2,103 @@
 
 # support smtp
 
+# This implementation uses Python (2 or 3), which is available in many environments.
+# If you don't have Python, try "mail" notification instead of "smtp".
+
+# SMTP_FROM="from@example.com"  # required
+# SMTP_TO="to@example.com"  # required
+# SMTP_HOST="smtp.example.com"  # required
+# SMTP_PORT="25"  # defaults to 25, 465 or 587 depending on SMTP_SECURE
+# SMTP_SECURE="none"  # one of "none", "ssl" (implicit TLS, TLS Wrapper), "tls" (explicit TLS, STARTTLS)
+# SMTP_USERNAME=""  # set if SMTP server requires login
+# SMTP_PASSWORD=""  # set if SMTP server requires login
+# SMTP_TIMEOUT="15"  # seconds for SMTP operations to timeout
+# SMTP_PYTHON="/path/to/python"  # defaults to system python3 or python
+
 smtp_send() {
+  # Find a Python interpreter:
+  SMTP_PYTHON="${SMTP_PYTHON:-$(_readaccountconf_mutable SMTP_PYTHON)}"
+  if [ "$SMTP_PYTHON" ]; then
+    if _exists "$SMTP_PYTHON"; then
+      _saveaccountconf_mutable SMTP_PYTHON "$SMTP_PYTHON"
+    else
+      _err "SMTP_PYTHON '$SMTP_PYTHON' does not exist."
+      return 1
+    fi
+  else
+    # No SMTP_PYTHON setting; try to run default Python.
+    # (This is not saved with the conf.)
+    if _exists python3; then
+      SMTP_PYTHON="python3"
+    elif _exists python; then
+      SMTP_PYTHON="python"
+    else
+      _err "Can't locate Python interpreter; please define SMTP_PYTHON."
+      return 1
+    fi
+  fi
+  _debug "SMTP_PYTHON" "$SMTP_PYTHON"
+  _debug "Python version" "$($SMTP_PYTHON --version 2>&1)"
+
+  # Validate other settings:
+  SMTP_FROM="${SMTP_FROM:-$(_readaccountconf_mutable SMTP_FROM)}"
+  if [ -z "$SMTP_FROM" ]; then
+    _err "You must define SMTP_FROM as the sender email address."
+    return 1
+  fi
+
+  SMTP_TO="${SMTP_TO:-$(_readaccountconf_mutable SMTP_TO)}"
+  if [ -z "$SMTP_TO" ]; then
+    _err "You must define SMTP_TO as the recipient email address."
+    return 1
+  fi
+
+  SMTP_HOST="${SMTP_HOST:-$(_readaccountconf_mutable SMTP_HOST)}"
+  if [ -z "$SMTP_HOST" ]; then
+    _err "You must define SMTP_HOST as the SMTP server hostname."
+    return 1
+  fi
+  SMTP_PORT="${SMTP_PORT:-$(_readaccountconf_mutable SMTP_PORT)}"
+
+  SMTP_SECURE="${SMTP_SECURE:-$(_readaccountconf_mutable SMTP_SECURE)}"
+  SMTP_SECURE="${SMTP_SECURE:-none}"
+  case "$SMTP_SECURE" in
+    "none") SMTP_DEFAULT_PORT="25";;
+    "ssl")  SMTP_DEFAULT_PORT="465";;
+    "tls")  SMTP_DEFAULT_PORT="587";;
+    *)
+      _err "Invalid SMTP_SECURE='$SMTP_SECURE'. It must be 'ssl', 'tls' or 'none'."
+      return 1
+      ;;
+  esac
+
+  SMTP_USERNAME="${SMTP_USERNAME:-$(_readaccountconf_mutable SMTP_USERNAME)}"
+  SMTP_PASSWORD="${SMTP_PASSWORD:-$(_readaccountconf_mutable SMTP_PASSWORD)}"
+
+  SMTP_TIMEOUT="${SMTP_TIMEOUT:-$(_readaccountconf_mutable SMTP_TIMEOUT)}"
+  SMTP_DEFAULT_TIMEOUT="15"
+
+  _saveaccountconf_mutable SMTP_FROM "$SMTP_FROM"
+  _saveaccountconf_mutable SMTP_TO "$SMTP_TO"
+  _saveaccountconf_mutable SMTP_HOST "$SMTP_HOST"
+  _saveaccountconf_mutable SMTP_PORT "$SMTP_PORT"
+  _saveaccountconf_mutable SMTP_SECURE "$SMTP_SECURE"
+  _saveaccountconf_mutable SMTP_USERNAME "$SMTP_USERNAME"
+  _saveaccountconf_mutable SMTP_PASSWORD "$SMTP_PASSWORD"
+  _saveaccountconf_mutable SMTP_TIMEOUT "$SMTP_TIMEOUT"
+
+  # Send the message:
+  if ! _smtp_send "$@"; then
+    _err "$smtp_send_output"
+    return 1
+  fi
+
+  return 0
+}
+
+# _send subject content statuscode
+# Send the message via Python using SMTP_* settings
+_smtp_send() {
   _subject="$1"
   _content="$2"
   _statusCode="$3" #0: success, 1: error 2($RENEW_SKIP): skipped
@@ -10,6 +106,91 @@ smtp_send() {
   _debug "_content" "$_content"
   _debug "_statusCode" "$_statusCode"
 
-  _err "Not implemented yet."
-  return 1
+  _debug "SMTP_FROM" "$SMTP_FROM"
+  _debug "SMTP_TO" "$SMTP_TO"
+  _debug "SMTP_HOST" "$SMTP_HOST"
+  _debug "SMTP_PORT" "$SMTP_PORT"
+  _debug "SMTP_DEFAULT_PORT" "$SMTP_DEFAULT_PORT"
+  _debug "SMTP_SECURE" "$SMTP_SECURE"
+  _debug "SMTP_USERNAME" "$SMTP_USERNAME"
+  _secure_debug "SMTP_PASSWORD" "$SMTP_PASSWORD"
+  _debug "SMTP_TIMEOUT" "$SMTP_TIMEOUT"
+  _debug "SMTP_DEFAULT_TIMEOUT" "$SMTP_DEFAULT_TIMEOUT"
+
+  if [ "${DEBUG:-$DEBUG_LEVEL_NONE}" -ge "$DEBUG_LEVEL_2" ]; then
+    # Output the SMTP server dialogue. (Note this will include SMTP_PASSWORD!)
+    smtp_debug="True"
+  else
+    smtp_debug=""
+  fi
+
+  # language=Python
+  smtp_send_output="$($SMTP_PYTHON <<EOF
+# This code is meant to work with either Python 2.7.x or Python 3.4+.
+try:
+    try:
+        from email.message import EmailMessage
+    except ImportError:
+        from email.mime.text import MIMEText as EmailMessage  # Python 2
+    from smtplib import SMTP, SMTP_SSL, SMTPException
+    from socket import error as SocketError
+except ImportError as err:
+    print("A required Python standard package is missing. This system may have"
+          " a reduced version of Python unsuitable for sending mail: %s" % err)
+    exit(1)
+
+smtp_debug = """$smtp_debug""" == "True"
+
+smtp_host = """$SMTP_HOST"""
+smtp_port = int("""${SMTP_PORT:-$SMTP_DEFAULT_PORT}""")
+smtp_secure = """$SMTP_SECURE"""
+username = """$SMTP_USERNAME"""
+password = """$SMTP_PASSWORD"""
+timeout=int("""${SMTP_TIMEOUT:-$SMTP_DEFAULT_TIMEOUT}""")  # seconds
+
+from_email="""$SMTP_FROM"""
+to_emails="""$SMTP_TO"""  # can be comma-separated
+subject="""$_subject"""
+content="""$_content"""
+
+try:
+    msg = EmailMessage()
+    msg.set_content(content)
+except (AttributeError, TypeError):
+    # Python 2 MIMEText
+    msg = EmailMessage(content)
+msg["Subject"] = subject
+msg["From"] = from_email
+msg["To"] = to_emails
+
+smtp = None
+try:
+    if smtp_secure == "ssl":
+        smtp = SMTP_SSL(smtp_host, smtp_port, timeout=timeout)
+    else:
+        smtp = SMTP(smtp_host, smtp_port, timeout=timeout)
+    smtp.set_debuglevel(smtp_debug)
+    if smtp_secure == "tls":
+        smtp.starttls()
+    if username or password:
+        smtp.login(username, password)
+    smtp.sendmail(msg["From"], msg["To"].split(","), msg.as_string())
+
+except SMTPException as err:
+    # Output just the error (skip the Python stack trace) for SMTP errors
+    print("Error sending: %r" % err)
+    exit(1)
+
+except SocketError as err:
+    print("Error connecting to %s:%d: %r" % (smtp_host, smtp_port, err))
+    exit(1)
+
+finally:
+    if smtp is not None:
+        smtp.quit()
+EOF
+)"
+  _ret=$?
+  _debug "smtp_send_output" "$smtp_send_output"
+  return "$_ret"
 }

From e48b6bd22daa3c9ddb3f029cfcc1613a57527330 Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Tue, 29 Dec 2020 17:10:36 -0800
Subject: [PATCH 02/17] Make shfmt happy

(I'm open to better ways of formatting the heredoc
that embeds the Python script.)
---
 notify/smtp.sh | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index 367021c8..6171cb9b 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -63,13 +63,13 @@ smtp_send() {
   SMTP_SECURE="${SMTP_SECURE:-$(_readaccountconf_mutable SMTP_SECURE)}"
   SMTP_SECURE="${SMTP_SECURE:-none}"
   case "$SMTP_SECURE" in
-    "none") SMTP_DEFAULT_PORT="25";;
-    "ssl")  SMTP_DEFAULT_PORT="465";;
-    "tls")  SMTP_DEFAULT_PORT="587";;
-    *)
-      _err "Invalid SMTP_SECURE='$SMTP_SECURE'. It must be 'ssl', 'tls' or 'none'."
-      return 1
-      ;;
+  "none") SMTP_DEFAULT_PORT="25" ;;
+  "ssl") SMTP_DEFAULT_PORT="465" ;;
+  "tls") SMTP_DEFAULT_PORT="587" ;;
+  *)
+    _err "Invalid SMTP_SECURE='$SMTP_SECURE'. It must be 'ssl', 'tls' or 'none'."
+    return 1
+    ;;
   esac
 
   SMTP_USERNAME="${SMTP_USERNAME:-$(_readaccountconf_mutable SMTP_USERNAME)}"
@@ -125,7 +125,8 @@ _smtp_send() {
   fi
 
   # language=Python
-  smtp_send_output="$($SMTP_PYTHON <<EOF
+  smtp_send_output="$(
+    $SMTP_PYTHON <<EOF
 # This code is meant to work with either Python 2.7.x or Python 3.4+.
 try:
     try:
@@ -189,7 +190,7 @@ finally:
     if smtp is not None:
         smtp.quit()
 EOF
-)"
+  )"
   _ret=$?
   _debug "smtp_send_output" "$smtp_send_output"
   return "$_ret"

From 2439bb30e89aefae4d7ee87d71505d6db61e969b Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Mon, 11 Jan 2021 11:46:26 -0800
Subject: [PATCH 03/17] Only save config if send is successful

---
 notify/smtp.sh | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index 6171cb9b..092bb2b9 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -78,6 +78,13 @@ smtp_send() {
   SMTP_TIMEOUT="${SMTP_TIMEOUT:-$(_readaccountconf_mutable SMTP_TIMEOUT)}"
   SMTP_DEFAULT_TIMEOUT="15"
 
+  # Send the message:
+  if ! _smtp_send "$@"; then
+    _err "$smtp_send_output"
+    return 1
+  fi
+
+  # Save remaining config if successful. (SMTP_PYTHON is saved earlier.)
   _saveaccountconf_mutable SMTP_FROM "$SMTP_FROM"
   _saveaccountconf_mutable SMTP_TO "$SMTP_TO"
   _saveaccountconf_mutable SMTP_HOST "$SMTP_HOST"
@@ -87,12 +94,6 @@ smtp_send() {
   _saveaccountconf_mutable SMTP_PASSWORD "$SMTP_PASSWORD"
   _saveaccountconf_mutable SMTP_TIMEOUT "$SMTP_TIMEOUT"
 
-  # Send the message:
-  if ! _smtp_send "$@"; then
-    _err "$smtp_send_output"
-    return 1
-  fi
-
   return 0
 }
 

From fe273b3829511febe42f9b854ba921213f7bedbb Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Mon, 11 Jan 2021 12:59:51 -0800
Subject: [PATCH 04/17] Add instructions for reporting bugs

---
 notify/smtp.sh | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index 092bb2b9..a74ce092 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -2,6 +2,8 @@
 
 # support smtp
 
+# Please report bugs to https://github.com/acmesh-official/acme.sh/issues/3358
+
 # This implementation uses Python (2 or 3), which is available in many environments.
 # If you don't have Python, try "mail" notification instead of "smtp".
 

From 557a747d55a91eb7f1ac97028decc5d141fb2466 Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Sun, 14 Feb 2021 15:47:51 -0800
Subject: [PATCH 05/17] Prep for curl or Python; clean up SMTP_* variable usage

---
 notify/smtp.sh | 207 ++++++++++++++++++++++++++++---------------------
 1 file changed, 120 insertions(+), 87 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index a74ce092..cb29d0f7 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -4,8 +4,8 @@
 
 # Please report bugs to https://github.com/acmesh-official/acme.sh/issues/3358
 
-# This implementation uses Python (2 or 3), which is available in many environments.
-# If you don't have Python, try "mail" notification instead of "smtp".
+# This implementation uses either curl or Python (3 or 2.7).
+# (See also the "mail" notify hook, which supports other ways to send mail.)
 
 # SMTP_FROM="from@example.com"  # required
 # SMTP_TO="to@example.com"  # required
@@ -14,79 +14,132 @@
 # SMTP_SECURE="none"  # one of "none", "ssl" (implicit TLS, TLS Wrapper), "tls" (explicit TLS, STARTTLS)
 # SMTP_USERNAME=""  # set if SMTP server requires login
 # SMTP_PASSWORD=""  # set if SMTP server requires login
-# SMTP_TIMEOUT="15"  # seconds for SMTP operations to timeout
-# SMTP_PYTHON="/path/to/python"  # defaults to system python3 or python
+# SMTP_TIMEOUT="30"  # seconds for SMTP operations to timeout
+# SMTP_BIN="/path/to/curl_or_python"  # default finds first of curl, python3, or python on PATH
 
+# subject content statuscode
 smtp_send() {
-  # Find a Python interpreter:
-  SMTP_PYTHON="${SMTP_PYTHON:-$(_readaccountconf_mutable SMTP_PYTHON)}"
-  if [ "$SMTP_PYTHON" ]; then
-    if _exists "$SMTP_PYTHON"; then
-      _saveaccountconf_mutable SMTP_PYTHON "$SMTP_PYTHON"
-    else
-      _err "SMTP_PYTHON '$SMTP_PYTHON' does not exist."
-      return 1
-    fi
-  else
-    # No SMTP_PYTHON setting; try to run default Python.
-    # (This is not saved with the conf.)
-    if _exists python3; then
-      SMTP_PYTHON="python3"
-    elif _exists python; then
-      SMTP_PYTHON="python"
-    else
-      _err "Can't locate Python interpreter; please define SMTP_PYTHON."
-      return 1
-    fi
-  fi
-  _debug "SMTP_PYTHON" "$SMTP_PYTHON"
-  _debug "Python version" "$($SMTP_PYTHON --version 2>&1)"
+  _SMTP_SUBJECT="$1"
+  _SMTP_CONTENT="$2"
+  # UNUSED: _statusCode="$3" # 0: success, 1: error 2($RENEW_SKIP): skipped
 
-  # Validate other settings:
+  # Load config:
   SMTP_FROM="${SMTP_FROM:-$(_readaccountconf_mutable SMTP_FROM)}"
+  SMTP_TO="${SMTP_TO:-$(_readaccountconf_mutable SMTP_TO)}"
+  SMTP_HOST="${SMTP_HOST:-$(_readaccountconf_mutable SMTP_HOST)}"
+  SMTP_PORT="${SMTP_PORT:-$(_readaccountconf_mutable SMTP_PORT)}"
+  SMTP_SECURE="${SMTP_SECURE:-$(_readaccountconf_mutable SMTP_SECURE)}"
+  SMTP_USERNAME="${SMTP_USERNAME:-$(_readaccountconf_mutable SMTP_USERNAME)}"
+  SMTP_PASSWORD="${SMTP_PASSWORD:-$(_readaccountconf_mutable SMTP_PASSWORD)}"
+  SMTP_TIMEOUT="${SMTP_TIMEOUT:-$(_readaccountconf_mutable SMTP_TIMEOUT)}"
+  SMTP_BIN="${SMTP_BIN:-$(_readaccountconf_mutable SMTP_BIN)}"
+
+  _debug "SMTP_FROM" "$SMTP_FROM"
+  _debug "SMTP_TO" "$SMTP_TO"
+  _debug "SMTP_HOST" "$SMTP_HOST"
+  _debug "SMTP_PORT" "$SMTP_PORT"
+  _debug "SMTP_SECURE" "$SMTP_SECURE"
+  _debug "SMTP_USERNAME" "$SMTP_USERNAME"
+  _secure_debug "SMTP_PASSWORD" "$SMTP_PASSWORD"
+  _debug "SMTP_TIMEOUT" "$SMTP_TIMEOUT"
+  _debug "SMTP_BIN" "$SMTP_BIN"
+
+  _debug "_SMTP_SUBJECT" "$_SMTP_SUBJECT"
+  _debug "_SMTP_CONTENT" "$_SMTP_CONTENT"
+
+  # Validate config and apply defaults:
+  # _SMTP_* variables are the resolved (with defaults) versions of SMTP_*.
+  # (The _SMTP_* versions will not be stored in account conf.)
+
+  if [ -n "$SMTP_BIN" ] && ! _exists "$SMTP_BIN"; then
+    _err "SMTP_BIN '$SMTP_BIN' does not exist."
+    return 1
+  fi
+  _SMTP_BIN="$SMTP_BIN"
+  if [ -z "$_SMTP_BIN" ]; then
+    # Look for a command that can communicate with an SMTP server.
+    # (Please don't add sendmail, ssmtp, mutt, mail, or msmtp here.
+    # Those are already handled by the "mail" notify hook.)
+    for cmd in curl python3 python2.7 python pypy3 pypy; do
+      if _exists "$cmd"; then
+        _SMTP_BIN="$cmd"
+        break
+      fi
+    done
+    if [ -z "$_SMTP_BIN" ]; then
+      _err "The smtp notify-hook requires curl or Python, but can't find any."
+      _err 'If you have one of them, define SMTP_BIN="/path/to/curl_or_python".'
+      _err 'Otherwise, see if you can use the "mail" notify-hook instead.'
+      return 1
+    fi
+    _debug "_SMTP_BIN" "$_SMTP_BIN"
+  fi
+
   if [ -z "$SMTP_FROM" ]; then
     _err "You must define SMTP_FROM as the sender email address."
     return 1
   fi
+  _SMTP_FROM="$SMTP_FROM"
 
-  SMTP_TO="${SMTP_TO:-$(_readaccountconf_mutable SMTP_TO)}"
   if [ -z "$SMTP_TO" ]; then
     _err "You must define SMTP_TO as the recipient email address."
     return 1
   fi
+  _SMTP_TO="$SMTP_TO"
 
-  SMTP_HOST="${SMTP_HOST:-$(_readaccountconf_mutable SMTP_HOST)}"
   if [ -z "$SMTP_HOST" ]; then
     _err "You must define SMTP_HOST as the SMTP server hostname."
     return 1
   fi
-  SMTP_PORT="${SMTP_PORT:-$(_readaccountconf_mutable SMTP_PORT)}"
+  _SMTP_HOST="$SMTP_HOST"
 
-  SMTP_SECURE="${SMTP_SECURE:-$(_readaccountconf_mutable SMTP_SECURE)}"
-  SMTP_SECURE="${SMTP_SECURE:-none}"
-  case "$SMTP_SECURE" in
-  "none") SMTP_DEFAULT_PORT="25" ;;
-  "ssl") SMTP_DEFAULT_PORT="465" ;;
-  "tls") SMTP_DEFAULT_PORT="587" ;;
+  _SMTP_SECURE="${SMTP_SECURE:-none}"
+  case "$_SMTP_SECURE" in
+  "none") smtp_default_port="25" ;;
+  "ssl") smtp_default_port="465" ;;
+  "tls") smtp_default_port="587" ;;
   *)
     _err "Invalid SMTP_SECURE='$SMTP_SECURE'. It must be 'ssl', 'tls' or 'none'."
     return 1
     ;;
   esac
 
-  SMTP_USERNAME="${SMTP_USERNAME:-$(_readaccountconf_mutable SMTP_USERNAME)}"
-  SMTP_PASSWORD="${SMTP_PASSWORD:-$(_readaccountconf_mutable SMTP_PASSWORD)}"
+  _SMTP_PORT="${SMTP_PORT:-$smtp_default_port}"
+  if [ -z "$SMTP_PORT" ]; then
+    _debug "_SMTP_PORT" "$_SMTP_PORT"
+  fi
 
-  SMTP_TIMEOUT="${SMTP_TIMEOUT:-$(_readaccountconf_mutable SMTP_TIMEOUT)}"
-  SMTP_DEFAULT_TIMEOUT="15"
+  _SMTP_USERNAME="$SMTP_USERNAME"
+  _SMTP_PASSWORD="$SMTP_PASSWORD"
+  _SMTP_TIMEOUT="${SMTP_TIMEOUT:-30}"
+
+  # Run with --debug 2 (or above) to echo the transcript of the SMTP session.
+  # Careful: this may include SMTP_PASSWORD in plaintext!
+  if [ "${DEBUG:-$DEBUG_LEVEL_NONE}" -ge "$DEBUG_LEVEL_2" ]; then
+    _SMTP_SHOW_TRANSCRIPT="True"
+  else
+    _SMTP_SHOW_TRANSCRIPT=""
+  fi
 
   # Send the message:
-  if ! _smtp_send "$@"; then
-    _err "$smtp_send_output"
+  case "$(basename "$_SMTP_BIN")" in
+  curl) _smtp_send=_smtp_send_curl ;;
+  py*) _smtp_send=_smtp_send_python ;;
+  *)
+    _err "Can't figure out how to invoke $_SMTP_BIN."
+    _err "Please re-run with --debug and report a bug."
+    return 1
+    ;;
+  esac
+
+  if ! smtp_output="$($_smtp_send)"; then
+    _err "Error sending message with $_SMTP_BIN."
+    _err "${smtp_output:-(No additional details; try --debug or --debug 2)}"
     return 1
   fi
 
-  # Save remaining config if successful. (SMTP_PYTHON is saved earlier.)
+  # Save config only if send was successful:
+  _saveaccountconf_mutable SMTP_BIN "$SMTP_BIN"
   _saveaccountconf_mutable SMTP_FROM "$SMTP_FROM"
   _saveaccountconf_mutable SMTP_TO "$SMTP_TO"
   _saveaccountconf_mutable SMTP_HOST "$SMTP_HOST"
@@ -99,37 +152,21 @@ smtp_send() {
   return 0
 }
 
-# _send subject content statuscode
-# Send the message via Python using SMTP_* settings
-_smtp_send() {
-  _subject="$1"
-  _content="$2"
-  _statusCode="$3" #0: success, 1: error 2($RENEW_SKIP): skipped
-  _debug "_subject" "$_subject"
-  _debug "_content" "$_content"
-  _debug "_statusCode" "$_statusCode"
 
-  _debug "SMTP_FROM" "$SMTP_FROM"
-  _debug "SMTP_TO" "$SMTP_TO"
-  _debug "SMTP_HOST" "$SMTP_HOST"
-  _debug "SMTP_PORT" "$SMTP_PORT"
-  _debug "SMTP_DEFAULT_PORT" "$SMTP_DEFAULT_PORT"
-  _debug "SMTP_SECURE" "$SMTP_SECURE"
-  _debug "SMTP_USERNAME" "$SMTP_USERNAME"
-  _secure_debug "SMTP_PASSWORD" "$SMTP_PASSWORD"
-  _debug "SMTP_TIMEOUT" "$SMTP_TIMEOUT"
-  _debug "SMTP_DEFAULT_TIMEOUT" "$SMTP_DEFAULT_TIMEOUT"
+# Send the message via curl using _SMTP_* variables
+_smtp_send_curl() {
+  # TODO: implement
+  echo "_smtp_send_curl not implemented"
+  return 1
+}
 
-  if [ "${DEBUG:-$DEBUG_LEVEL_NONE}" -ge "$DEBUG_LEVEL_2" ]; then
-    # Output the SMTP server dialogue. (Note this will include SMTP_PASSWORD!)
-    smtp_debug="True"
-  else
-    smtp_debug=""
-  fi
+
+# Send the message via Python using _SMTP_* variables
+_smtp_send_python() {
+  _debug "Python version" "$("$_SMTP_BIN" --version 2>&1)"
 
   # language=Python
-  smtp_send_output="$(
-    $SMTP_PYTHON <<EOF
+  "$_SMTP_BIN" <<EOF
 # This code is meant to work with either Python 2.7.x or Python 3.4+.
 try:
     try:
@@ -143,19 +180,19 @@ except ImportError as err:
           " a reduced version of Python unsuitable for sending mail: %s" % err)
     exit(1)
 
-smtp_debug = """$smtp_debug""" == "True"
+show_transcript = """$_SMTP_SHOW_TRANSCRIPT""" == "True"
 
-smtp_host = """$SMTP_HOST"""
-smtp_port = int("""${SMTP_PORT:-$SMTP_DEFAULT_PORT}""")
-smtp_secure = """$SMTP_SECURE"""
-username = """$SMTP_USERNAME"""
-password = """$SMTP_PASSWORD"""
-timeout=int("""${SMTP_TIMEOUT:-$SMTP_DEFAULT_TIMEOUT}""")  # seconds
+smtp_host = """$_SMTP_HOST"""
+smtp_port = int("""$_SMTP_PORT""")
+smtp_secure = """$_SMTP_SECURE"""
+username = """$_SMTP_USERNAME"""
+password = """$_SMTP_PASSWORD"""
+timeout=int("""$_SMTP_TIMEOUT""")  # seconds
 
-from_email="""$SMTP_FROM"""
-to_emails="""$SMTP_TO"""  # can be comma-separated
-subject="""$_subject"""
-content="""$_content"""
+from_email="""$_SMTP_FROM"""
+to_emails="""$_SMTP_TO"""  # can be comma-separated
+subject="""$_SMTP_SUBJECT"""
+content="""$_SMTP_CONTENT"""
 
 try:
     msg = EmailMessage()
@@ -173,7 +210,7 @@ try:
         smtp = SMTP_SSL(smtp_host, smtp_port, timeout=timeout)
     else:
         smtp = SMTP(smtp_host, smtp_port, timeout=timeout)
-    smtp.set_debuglevel(smtp_debug)
+    smtp.set_debuglevel(show_transcript)
     if smtp_secure == "tls":
         smtp.starttls()
     if username or password:
@@ -193,8 +230,4 @@ finally:
     if smtp is not None:
         smtp.quit()
 EOF
-  )"
-  _ret=$?
-  _debug "smtp_send_output" "$smtp_send_output"
-  return "$_ret"
 }

From 30dae70e2b2ea4a3f81f7bf1617a2652f8bf2dfc Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Sun, 14 Feb 2021 19:56:23 -0800
Subject: [PATCH 06/17] Implement curl version of smtp notify-hook

---
 notify/smtp.sh | 111 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 105 insertions(+), 6 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index cb29d0f7..44a5821f 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -127,14 +127,16 @@ smtp_send() {
   py*) _smtp_send=_smtp_send_python ;;
   *)
     _err "Can't figure out how to invoke $_SMTP_BIN."
-    _err "Please re-run with --debug and report a bug."
+    _err "Check your SMTP_BIN setting."
     return 1
     ;;
   esac
 
   if ! smtp_output="$($_smtp_send)"; then
     _err "Error sending message with $_SMTP_BIN."
-    _err "${smtp_output:-(No additional details; try --debug or --debug 2)}"
+    if [ -n "$smtp_output" ]; then
+      _err "$smtp_output"
+    fi
     return 1
   fi
 
@@ -152,12 +154,109 @@ smtp_send() {
   return 0
 }
 
-
 # Send the message via curl using _SMTP_* variables
 _smtp_send_curl() {
-  # TODO: implement
-  echo "_smtp_send_curl not implemented"
-  return 1
+  # curl passes --mail-from and --mail-rcpt directly to the SMTP protocol without
+  # additional parsing, and SMTP requires addr-spec only (no display names).
+  # In the future, maybe try to parse the addr-spec out for curl args (non-trivial).
+  if _email_has_display_name "$_SMTP_FROM"; then
+    _err "curl smtp only allows a simple email address in SMTP_FROM."
+    _err "Change your SMTP_FROM='$SMTP_FROM' to remove the display name."
+    return 1
+  fi
+  if _email_has_display_name "$_SMTP_TO"; then
+    _err "curl smtp only allows simple email addresses in SMTP_TO."
+    _err "Change your SMTP_TO='$SMTP_TO' to remove the display name(s)."
+    return 1
+  fi
+
+  # Build curl args in $@
+
+  case "$_SMTP_SECURE" in
+  none)
+    set -- --url "smtp://${_SMTP_HOST}:${_SMTP_PORT}"
+    ;;
+  ssl)
+    set -- --url "smtps://${_SMTP_HOST}:${_SMTP_PORT}"
+    ;;
+  tls)
+    set -- --url "smtp://${_SMTP_HOST}:${_SMTP_PORT}" --ssl-reqd
+    ;;
+  *)
+    # This will only occur if someone adds a new SMTP_SECURE option above
+    # without updating this code for it.
+    _err "Unhandled _SMTP_SECURE='$_SMTP_SECURE' in _smtp_send_curl"
+    _err "Please re-run with --debug and report a bug."
+    return 1
+    ;;
+  esac
+
+  set -- "$@" \
+    --upload-file - \
+    --mail-from "$_SMTP_FROM" \
+    --max-time "$_SMTP_TIMEOUT"
+
+  # Burst comma-separated $_SMTP_TO into individual --mail-rcpt args.
+  _to="${_SMTP_TO},"
+  while [ -n "$_to" ]; do
+    _rcpt="${_to%%,*}"
+    _to="${_to#*,}"
+    set -- "$@" --mail-rcpt "$_rcpt"
+  done
+
+  _smtp_login="${_SMTP_USERNAME}:${_SMTP_PASSWORD}"
+  if [ "$_smtp_login" != ":" ]; then
+    set -- "$@" --user "$_smtp_login"
+  fi
+
+  if [ "$_SMTP_SHOW_TRANSCRIPT" = "True" ]; then
+    set -- "$@" --verbose
+  else
+    set -- "$@" --silent --show-error
+  fi
+
+  raw_message="$(_smtp_raw_message)"
+
+  _debug2 "curl command:" "$_SMTP_BIN" "$*"
+  _debug2 "raw_message:\n$raw_message"
+
+  echo "$raw_message" | "$_SMTP_BIN" "$@"
+}
+
+# Output an RFC-822 / RFC-5322 email message using _SMTP_* variables
+_smtp_raw_message() {
+  echo "From: $_SMTP_FROM"
+  echo "To: $_SMTP_TO"
+  echo "Subject: $(_mime_encoded_word "$_SMTP_SUBJECT")"
+  if _exists date; then
+    echo "Date: $(date +'%a, %-d %b %Y %H:%M:%S %z')"
+  fi
+  echo "Content-Type: text/plain; charset=utf-8"
+  echo "X-Mailer: acme.sh --notify-hook smtp"
+  echo
+  echo "$_SMTP_CONTENT"
+}
+
+# Convert text to RFC-2047 MIME "encoded word" format if it contains non-ASCII chars
+# text
+_mime_encoded_word() {
+  _text="$1"
+  # (regex character ranges like [a-z] can be locale-dependent; enumerate ASCII chars to avoid that)
+  _ascii='] $`"'"[!#%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ~^_abcdefghijklmnopqrstuvwxyz{|}~-"
+  if expr "$_text" : "^.*[^$_ascii]" >/dev/null; then
+    # At least one non-ASCII char; convert entire thing to encoded word
+    printf "%s" "=?UTF-8?B?$(printf "%s" "$_text" | _base64)?="
+  else
+    # Just printable ASCII, no conversion needed
+    printf "%s" "$_text"
+  fi
+}
+
+# Simple check for display name in an email address (< > or ")
+# email
+_email_has_display_name() {
+  _email="$1"
+  expr "$_email" : '^.*[<>"]' > /dev/null
 }
 
 

From ffe7ef476439df04e1878ea08f0c6b3eb91653c6 Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Sun, 14 Feb 2021 20:06:07 -0800
Subject: [PATCH 07/17] More than one blank line is an abomination, apparently

I will not try to use whitespace to group code visually
---
 notify/smtp.sh | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index 44a5821f..c9927e3e 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -256,10 +256,9 @@ _mime_encoded_word() {
 # email
 _email_has_display_name() {
   _email="$1"
-  expr "$_email" : '^.*[<>"]' > /dev/null
+  expr "$_email" : '^.*[<>"]' >/dev/null
 }
 
-
 # Send the message via Python using _SMTP_* variables
 _smtp_send_python() {
   _debug "Python version" "$("$_SMTP_BIN" --version 2>&1)"

From 6ff75f9a9fe906ed1c1b9cbf637b0e749ba9e127 Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Mon, 15 Feb 2021 12:23:48 -0800
Subject: [PATCH 08/17] Use PROJECT_NAME and VER for X-Mailer header

Also add X-Mailer header to Python version
---
 notify/smtp.sh | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index c9927e3e..bb71a563 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -112,6 +112,7 @@ smtp_send() {
   _SMTP_USERNAME="$SMTP_USERNAME"
   _SMTP_PASSWORD="$SMTP_PASSWORD"
   _SMTP_TIMEOUT="${SMTP_TIMEOUT:-30}"
+  _SMTP_X_MAILER="${PROJECT_NAME} ${VER} --notify-hook smtp"
 
   # Run with --debug 2 (or above) to echo the transcript of the SMTP session.
   # Careful: this may include SMTP_PASSWORD in plaintext!
@@ -232,7 +233,7 @@ _smtp_raw_message() {
     echo "Date: $(date +'%a, %-d %b %Y %H:%M:%S %z')"
   fi
   echo "Content-Type: text/plain; charset=utf-8"
-  echo "X-Mailer: acme.sh --notify-hook smtp"
+  echo "X-Mailer: $_SMTP_X_MAILER"
   echo
   echo "$_SMTP_CONTENT"
 }
@@ -286,6 +287,7 @@ smtp_secure = """$_SMTP_SECURE"""
 username = """$_SMTP_USERNAME"""
 password = """$_SMTP_PASSWORD"""
 timeout=int("""$_SMTP_TIMEOUT""")  # seconds
+x_mailer="""$_SMTP_X_MAILER"""
 
 from_email="""$_SMTP_FROM"""
 to_emails="""$_SMTP_TO"""  # can be comma-separated
@@ -301,6 +303,7 @@ except (AttributeError, TypeError):
 msg["Subject"] = subject
 msg["From"] = from_email
 msg["To"] = to_emails
+msg["X-Mailer"] = x_mailer
 
 smtp = None
 try:

From 585c0c381852ebc796018a79d02fdac3f5666773 Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Tue, 16 Feb 2021 09:33:39 -0800
Subject: [PATCH 09/17] Add _clearaccountconf_mutable()

---
 acme.sh | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/acme.sh b/acme.sh
index a9301e10..bb4134de 100755
--- a/acme.sh
+++ b/acme.sh
@@ -2279,6 +2279,13 @@ _clearaccountconf() {
   _clear_conf "$ACCOUNT_CONF_PATH" "$1"
 }
 
+#key
+_clearaccountconf_mutable() {
+  _clearaccountconf "SAVED_$1"
+  #remove later
+  _clearaccountconf "$1"
+}
+
 #_savecaconf  key  value
 _savecaconf() {
   _save_conf "$CA_CONF" "$1" "$2"

From 6e77756d6a0b3d71f0ecc014d6336a8e6b025db1 Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Tue, 16 Feb 2021 12:49:27 -0800
Subject: [PATCH 10/17] Rework read/save config to not save default values

Add and use _readaccountconf_mutable_default and
_saveaccountconf_mutable_default helpers to capture
common default value handling.

New approach also eliminates need for separate
underscore-prefixed version of each conf var.
---
 notify/smtp.sh | 253 +++++++++++++++++++++++++++++--------------------
 1 file changed, 148 insertions(+), 105 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index bb71a563..85801604 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -17,155 +17,150 @@
 # SMTP_TIMEOUT="30"  # seconds for SMTP operations to timeout
 # SMTP_BIN="/path/to/curl_or_python"  # default finds first of curl, python3, or python on PATH
 
+SMTP_SECURE_DEFAULT="none"
+SMTP_TIMEOUT_DEFAULT="30"
+
 # subject content statuscode
 smtp_send() {
-  _SMTP_SUBJECT="$1"
-  _SMTP_CONTENT="$2"
+  SMTP_SUBJECT="$1"
+  SMTP_CONTENT="$2"
   # UNUSED: _statusCode="$3" # 0: success, 1: error 2($RENEW_SKIP): skipped
 
-  # Load config:
-  SMTP_FROM="${SMTP_FROM:-$(_readaccountconf_mutable SMTP_FROM)}"
-  SMTP_TO="${SMTP_TO:-$(_readaccountconf_mutable SMTP_TO)}"
-  SMTP_HOST="${SMTP_HOST:-$(_readaccountconf_mutable SMTP_HOST)}"
-  SMTP_PORT="${SMTP_PORT:-$(_readaccountconf_mutable SMTP_PORT)}"
-  SMTP_SECURE="${SMTP_SECURE:-$(_readaccountconf_mutable SMTP_SECURE)}"
-  SMTP_USERNAME="${SMTP_USERNAME:-$(_readaccountconf_mutable SMTP_USERNAME)}"
-  SMTP_PASSWORD="${SMTP_PASSWORD:-$(_readaccountconf_mutable SMTP_PASSWORD)}"
-  SMTP_TIMEOUT="${SMTP_TIMEOUT:-$(_readaccountconf_mutable SMTP_TIMEOUT)}"
-  SMTP_BIN="${SMTP_BIN:-$(_readaccountconf_mutable SMTP_BIN)}"
-
-  _debug "SMTP_FROM" "$SMTP_FROM"
-  _debug "SMTP_TO" "$SMTP_TO"
-  _debug "SMTP_HOST" "$SMTP_HOST"
-  _debug "SMTP_PORT" "$SMTP_PORT"
-  _debug "SMTP_SECURE" "$SMTP_SECURE"
-  _debug "SMTP_USERNAME" "$SMTP_USERNAME"
-  _secure_debug "SMTP_PASSWORD" "$SMTP_PASSWORD"
-  _debug "SMTP_TIMEOUT" "$SMTP_TIMEOUT"
-  _debug "SMTP_BIN" "$SMTP_BIN"
-
-  _debug "_SMTP_SUBJECT" "$_SMTP_SUBJECT"
-  _debug "_SMTP_CONTENT" "$_SMTP_CONTENT"
-
-  # Validate config and apply defaults:
-  # _SMTP_* variables are the resolved (with defaults) versions of SMTP_*.
-  # (The _SMTP_* versions will not be stored in account conf.)
-
+  # Load and validate config:
+  SMTP_BIN="$(_readaccountconf_mutable_default SMTP_BIN)"
   if [ -n "$SMTP_BIN" ] && ! _exists "$SMTP_BIN"; then
     _err "SMTP_BIN '$SMTP_BIN' does not exist."
     return 1
   fi
-  _SMTP_BIN="$SMTP_BIN"
-  if [ -z "$_SMTP_BIN" ]; then
+  if [ -z "$SMTP_BIN" ]; then
     # Look for a command that can communicate with an SMTP server.
     # (Please don't add sendmail, ssmtp, mutt, mail, or msmtp here.
     # Those are already handled by the "mail" notify hook.)
     for cmd in curl python3 python2.7 python pypy3 pypy; do
       if _exists "$cmd"; then
-        _SMTP_BIN="$cmd"
+        SMTP_BIN="$cmd"
         break
       fi
     done
-    if [ -z "$_SMTP_BIN" ]; then
+    if [ -z "$SMTP_BIN" ]; then
       _err "The smtp notify-hook requires curl or Python, but can't find any."
       _err 'If you have one of them, define SMTP_BIN="/path/to/curl_or_python".'
       _err 'Otherwise, see if you can use the "mail" notify-hook instead.'
       return 1
     fi
-    _debug "_SMTP_BIN" "$_SMTP_BIN"
   fi
+  _debug SMTP_BIN "$SMTP_BIN"
+  _saveaccountconf_mutable_default SMTP_BIN "$SMTP_BIN"
 
+  SMTP_FROM="$(_readaccountconf_mutable_default SMTP_FROM)"
   if [ -z "$SMTP_FROM" ]; then
     _err "You must define SMTP_FROM as the sender email address."
     return 1
   fi
-  _SMTP_FROM="$SMTP_FROM"
+  _debug SMTP_FROM "$SMTP_FROM"
+  _saveaccountconf_mutable_default SMTP_FROM "$SMTP_FROM"
 
+  SMTP_TO="$(_readaccountconf_mutable_default SMTP_TO)"
   if [ -z "$SMTP_TO" ]; then
     _err "You must define SMTP_TO as the recipient email address."
     return 1
   fi
-  _SMTP_TO="$SMTP_TO"
+  _debug SMTP_TO "$SMTP_TO"
+  _saveaccountconf_mutable_default SMTP_TO "$SMTP_TO"
 
+  SMTP_HOST="$(_readaccountconf_mutable_default SMTP_HOST)"
   if [ -z "$SMTP_HOST" ]; then
     _err "You must define SMTP_HOST as the SMTP server hostname."
     return 1
   fi
-  _SMTP_HOST="$SMTP_HOST"
+  _debug SMTP_HOST "$SMTP_HOST"
+  _saveaccountconf_mutable_default SMTP_HOST "$SMTP_HOST"
 
-  _SMTP_SECURE="${SMTP_SECURE:-none}"
-  case "$_SMTP_SECURE" in
-  "none") smtp_default_port="25" ;;
-  "ssl") smtp_default_port="465" ;;
-  "tls") smtp_default_port="587" ;;
+  SMTP_SECURE="$(_readaccountconf_mutable_default SMTP_SECURE "$SMTP_SECURE_DEFAULT")"
+  case "$SMTP_SECURE" in
+  "none") smtp_port_default="25" ;;
+  "ssl") smtp_port_default="465" ;;
+  "tls") smtp_port_default="587" ;;
   *)
     _err "Invalid SMTP_SECURE='$SMTP_SECURE'. It must be 'ssl', 'tls' or 'none'."
     return 1
     ;;
   esac
+  _debug SMTP_SECURE "$SMTP_SECURE"
+  _saveaccountconf_mutable_default SMTP_SECURE "$SMTP_SECURE" "$SMTP_SECURE_DEFAULT"
 
-  _SMTP_PORT="${SMTP_PORT:-$smtp_default_port}"
-  if [ -z "$SMTP_PORT" ]; then
-    _debug "_SMTP_PORT" "$_SMTP_PORT"
-  fi
+  SMTP_PORT="$(_readaccountconf_mutable_default SMTP_PORT "$smtp_port_default")"
+  case "$SMTP_PORT" in
+  *[!0-9]*)
+    _err "Invalid SMTP_PORT='$SMTP_PORT'. It must be a port number."
+    return 1
+    ;;
+  esac
+  _debug SMTP_PORT "$SMTP_PORT"
+  _saveaccountconf_mutable_default SMTP_PORT "$SMTP_PORT" "$smtp_port_default"
 
-  _SMTP_USERNAME="$SMTP_USERNAME"
-  _SMTP_PASSWORD="$SMTP_PASSWORD"
-  _SMTP_TIMEOUT="${SMTP_TIMEOUT:-30}"
-  _SMTP_X_MAILER="${PROJECT_NAME} ${VER} --notify-hook smtp"
+  SMTP_USERNAME="$(_readaccountconf_mutable_default SMTP_USERNAME)"
+  _debug SMTP_USERNAME "$SMTP_USERNAME"
+  _saveaccountconf_mutable_default SMTP_USERNAME "$SMTP_USERNAME"
+
+  SMTP_PASSWORD="$(_readaccountconf_mutable_default SMTP_PASSWORD)"
+  _secure_debug SMTP_PASSWORD "$SMTP_PASSWORD"
+  _saveaccountconf_mutable_default SMTP_PASSWORD "$SMTP_PASSWORD"
+
+  SMTP_TIMEOUT="$(_readaccountconf_mutable_default SMTP_TIMEOUT "$SMTP_TIMEOUT_DEFAULT")"
+  _debug SMTP_TIMEOUT "$SMTP_TIMEOUT"
+  _saveaccountconf_mutable_default SMTP_TIMEOUT "$SMTP_TIMEOUT" "$SMTP_TIMEOUT_DEFAULT"
+
+  SMTP_X_MAILER="${PROJECT_NAME} ${VER} --notify-hook smtp"
 
   # Run with --debug 2 (or above) to echo the transcript of the SMTP session.
   # Careful: this may include SMTP_PASSWORD in plaintext!
   if [ "${DEBUG:-$DEBUG_LEVEL_NONE}" -ge "$DEBUG_LEVEL_2" ]; then
-    _SMTP_SHOW_TRANSCRIPT="True"
+    SMTP_SHOW_TRANSCRIPT="True"
   else
-    _SMTP_SHOW_TRANSCRIPT=""
+    SMTP_SHOW_TRANSCRIPT=""
   fi
 
+  _debug SMTP_SUBJECT "$SMTP_SUBJECT"
+  _debug SMTP_CONTENT "$SMTP_CONTENT"
+
   # Send the message:
-  case "$(basename "$_SMTP_BIN")" in
+  case "$(basename "$SMTP_BIN")" in
   curl) _smtp_send=_smtp_send_curl ;;
   py*) _smtp_send=_smtp_send_python ;;
   *)
-    _err "Can't figure out how to invoke $_SMTP_BIN."
+    _err "Can't figure out how to invoke '$SMTP_BIN'."
     _err "Check your SMTP_BIN setting."
     return 1
     ;;
   esac
 
   if ! smtp_output="$($_smtp_send)"; then
-    _err "Error sending message with $_SMTP_BIN."
+    _err "Error sending message with $SMTP_BIN."
     if [ -n "$smtp_output" ]; then
       _err "$smtp_output"
     fi
     return 1
   fi
 
-  # Save config only if send was successful:
-  _saveaccountconf_mutable SMTP_BIN "$SMTP_BIN"
-  _saveaccountconf_mutable SMTP_FROM "$SMTP_FROM"
-  _saveaccountconf_mutable SMTP_TO "$SMTP_TO"
-  _saveaccountconf_mutable SMTP_HOST "$SMTP_HOST"
-  _saveaccountconf_mutable SMTP_PORT "$SMTP_PORT"
-  _saveaccountconf_mutable SMTP_SECURE "$SMTP_SECURE"
-  _saveaccountconf_mutable SMTP_USERNAME "$SMTP_USERNAME"
-  _saveaccountconf_mutable SMTP_PASSWORD "$SMTP_PASSWORD"
-  _saveaccountconf_mutable SMTP_TIMEOUT "$SMTP_TIMEOUT"
-
   return 0
 }
 
-# Send the message via curl using _SMTP_* variables
+##
+## curl smtp sending
+##
+
+# Send the message via curl using SMTP_* variables
 _smtp_send_curl() {
   # curl passes --mail-from and --mail-rcpt directly to the SMTP protocol without
   # additional parsing, and SMTP requires addr-spec only (no display names).
   # In the future, maybe try to parse the addr-spec out for curl args (non-trivial).
-  if _email_has_display_name "$_SMTP_FROM"; then
+  if _email_has_display_name "$SMTP_FROM"; then
     _err "curl smtp only allows a simple email address in SMTP_FROM."
     _err "Change your SMTP_FROM='$SMTP_FROM' to remove the display name."
     return 1
   fi
-  if _email_has_display_name "$_SMTP_TO"; then
+  if _email_has_display_name "$SMTP_TO"; then
     _err "curl smtp only allows simple email addresses in SMTP_TO."
     _err "Change your SMTP_TO='$SMTP_TO' to remove the display name(s)."
     return 1
@@ -173,20 +168,20 @@ _smtp_send_curl() {
 
   # Build curl args in $@
 
-  case "$_SMTP_SECURE" in
+  case "$SMTP_SECURE" in
   none)
-    set -- --url "smtp://${_SMTP_HOST}:${_SMTP_PORT}"
+    set -- --url "smtp://${SMTP_HOST}:${SMTP_PORT}"
     ;;
   ssl)
-    set -- --url "smtps://${_SMTP_HOST}:${_SMTP_PORT}"
+    set -- --url "smtps://${SMTP_HOST}:${SMTP_PORT}"
     ;;
   tls)
-    set -- --url "smtp://${_SMTP_HOST}:${_SMTP_PORT}" --ssl-reqd
+    set -- --url "smtp://${SMTP_HOST}:${SMTP_PORT}" --ssl-reqd
     ;;
   *)
     # This will only occur if someone adds a new SMTP_SECURE option above
     # without updating this code for it.
-    _err "Unhandled _SMTP_SECURE='$_SMTP_SECURE' in _smtp_send_curl"
+    _err "Unhandled SMTP_SECURE='$SMTP_SECURE' in _smtp_send_curl"
     _err "Please re-run with --debug and report a bug."
     return 1
     ;;
@@ -194,23 +189,23 @@ _smtp_send_curl() {
 
   set -- "$@" \
     --upload-file - \
-    --mail-from "$_SMTP_FROM" \
-    --max-time "$_SMTP_TIMEOUT"
+    --mail-from "$SMTP_FROM" \
+    --max-time "$SMTP_TIMEOUT"
 
-  # Burst comma-separated $_SMTP_TO into individual --mail-rcpt args.
-  _to="${_SMTP_TO},"
+  # Burst comma-separated $SMTP_TO into individual --mail-rcpt args.
+  _to="${SMTP_TO},"
   while [ -n "$_to" ]; do
     _rcpt="${_to%%,*}"
     _to="${_to#*,}"
     set -- "$@" --mail-rcpt "$_rcpt"
   done
 
-  _smtp_login="${_SMTP_USERNAME}:${_SMTP_PASSWORD}"
+  _smtp_login="${SMTP_USERNAME}:${SMTP_PASSWORD}"
   if [ "$_smtp_login" != ":" ]; then
     set -- "$@" --user "$_smtp_login"
   fi
 
-  if [ "$_SMTP_SHOW_TRANSCRIPT" = "True" ]; then
+  if [ "$SMTP_SHOW_TRANSCRIPT" = "True" ]; then
     set -- "$@" --verbose
   else
     set -- "$@" --silent --show-error
@@ -218,24 +213,24 @@ _smtp_send_curl() {
 
   raw_message="$(_smtp_raw_message)"
 
-  _debug2 "curl command:" "$_SMTP_BIN" "$*"
+  _debug2 "curl command:" "$SMTP_BIN" "$*"
   _debug2 "raw_message:\n$raw_message"
 
-  echo "$raw_message" | "$_SMTP_BIN" "$@"
+  echo "$raw_message" | "$SMTP_BIN" "$@"
 }
 
-# Output an RFC-822 / RFC-5322 email message using _SMTP_* variables
+# Output an RFC-822 / RFC-5322 email message using SMTP_* variables
 _smtp_raw_message() {
-  echo "From: $_SMTP_FROM"
-  echo "To: $_SMTP_TO"
-  echo "Subject: $(_mime_encoded_word "$_SMTP_SUBJECT")"
+  echo "From: $SMTP_FROM"
+  echo "To: $SMTP_TO"
+  echo "Subject: $(_mime_encoded_word "$SMTP_SUBJECT")"
   if _exists date; then
     echo "Date: $(date +'%a, %-d %b %Y %H:%M:%S %z')"
   fi
   echo "Content-Type: text/plain; charset=utf-8"
-  echo "X-Mailer: $_SMTP_X_MAILER"
+  echo "X-Mailer: $SMTP_X_MAILER"
   echo
-  echo "$_SMTP_CONTENT"
+  echo "$SMTP_CONTENT"
 }
 
 # Convert text to RFC-2047 MIME "encoded word" format if it contains non-ASCII chars
@@ -260,12 +255,16 @@ _email_has_display_name() {
   expr "$_email" : '^.*[<>"]' >/dev/null
 }
 
-# Send the message via Python using _SMTP_* variables
+##
+## Python smtp sending
+##
+
+# Send the message via Python using SMTP_* variables
 _smtp_send_python() {
-  _debug "Python version" "$("$_SMTP_BIN" --version 2>&1)"
+  _debug "Python version" "$("$SMTP_BIN" --version 2>&1)"
 
   # language=Python
-  "$_SMTP_BIN" <<EOF
+  "$SMTP_BIN" <<PYTHON
 # This code is meant to work with either Python 2.7.x or Python 3.4+.
 try:
     try:
@@ -279,20 +278,20 @@ except ImportError as err:
           " a reduced version of Python unsuitable for sending mail: %s" % err)
     exit(1)
 
-show_transcript = """$_SMTP_SHOW_TRANSCRIPT""" == "True"
+show_transcript = """$SMTP_SHOW_TRANSCRIPT""" == "True"
 
-smtp_host = """$_SMTP_HOST"""
-smtp_port = int("""$_SMTP_PORT""")
-smtp_secure = """$_SMTP_SECURE"""
-username = """$_SMTP_USERNAME"""
-password = """$_SMTP_PASSWORD"""
-timeout=int("""$_SMTP_TIMEOUT""")  # seconds
-x_mailer="""$_SMTP_X_MAILER"""
+smtp_host = """$SMTP_HOST"""
+smtp_port = int("""$SMTP_PORT""")
+smtp_secure = """$SMTP_SECURE"""
+username = """$SMTP_USERNAME"""
+password = """$SMTP_PASSWORD"""
+timeout=int("""$SMTP_TIMEOUT""")  # seconds
+x_mailer="""$SMTP_X_MAILER"""
 
-from_email="""$_SMTP_FROM"""
-to_emails="""$_SMTP_TO"""  # can be comma-separated
-subject="""$_SMTP_SUBJECT"""
-content="""$_SMTP_CONTENT"""
+from_email="""$SMTP_FROM"""
+to_emails="""$SMTP_TO"""  # can be comma-separated
+subject="""$SMTP_SUBJECT"""
+content="""$SMTP_CONTENT"""
 
 try:
     msg = EmailMessage()
@@ -330,5 +329,49 @@ except SocketError as err:
 finally:
     if smtp is not None:
         smtp.quit()
-EOF
+PYTHON
+}
+
+##
+## Conf helpers
+##
+
+#_readaccountconf_mutable_default name default_value
+# Given a name like MY_CONF:
+#   - if MY_CONF is set and non-empty, output $MY_CONF
+#   - if MY_CONF is set _empty_, output $default_value
+#     (lets user `export MY_CONF=` to clear previous saved value
+#     and return to default, without user having to know default)
+#   - otherwise if _readaccountconf_mutable $name is non-empty, return that
+#     (value of SAVED_MY_CONF from account.conf)
+#   - otherwise output $default_value
+_readaccountconf_mutable_default() {
+  _name="$1"
+  _default_value="$2"
+
+  eval "_value=\"\$$_name\""
+  eval "_explicit_empty_value=\"\${${_name}+empty}\""
+  if [ -z "${_value}" ] && [ "${_explicit_empty_value:-}" != "empty" ]; then
+    _value="$(_readaccountconf_mutable "$_name")"
+  fi
+  if [ -z "${_value}" ]; then
+    _value="$_default_value"
+  fi
+  printf "%s" "$_value"
+}
+
+#_saveaccountconf_mutable_default name value default_value base64encode
+# Like _saveaccountconf_mutable, but if value is default_value
+# then _clearaccountconf_mutable instead
+_saveaccountconf_mutable_default() {
+  _name="$1"
+  _value="$2"
+  _default_value="$3"
+  _base64encode="$4"
+
+  if [ "$_value" != "$_default_value" ]; then
+    _saveaccountconf_mutable "$_name" "$_value" "$_base64encode"
+  else
+    _clearaccountconf_mutable "$_name"
+  fi
 }

From b36247a091b20bc5dfc23be36e19f73f89e1eae1 Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Tue, 16 Feb 2021 13:13:26 -0800
Subject: [PATCH 11/17] Implement _rfc2822_date helper

---
 notify/smtp.sh | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index 85801604..43536cd2 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -224,9 +224,7 @@ _smtp_raw_message() {
   echo "From: $SMTP_FROM"
   echo "To: $SMTP_TO"
   echo "Subject: $(_mime_encoded_word "$SMTP_SUBJECT")"
-  if _exists date; then
-    echo "Date: $(date +'%a, %-d %b %Y %H:%M:%S %z')"
-  fi
+  echo "Date: $(_rfc2822_date)"
   echo "Content-Type: text/plain; charset=utf-8"
   echo "X-Mailer: $SMTP_X_MAILER"
   echo
@@ -248,6 +246,19 @@ _mime_encoded_word() {
   fi
 }
 
+# Output current date in RFC-2822 Section 3.3 format as required in email headers
+# (e.g., "Mon, 15 Feb 2021 14:22:01 -0800")
+_rfc2822_date() {
+  # Notes:
+  #   - this is deliberately not UTC, because it "SHOULD express local time" per spec
+  #   - the spec requires weekday and month in the C locale (English), not localized
+  #   - this date format specifier has been tested on Linux, Mac, Solaris and FreeBSD
+  _old_lc_time="$LC_TIME"
+  LC_TIME=C
+  date +'%a, %-d %b %Y %H:%M:%S %z'
+  LC_TIME="$_old_lc_time"
+}
+
 # Simple check for display name in an email address (< > or ")
 # email
 _email_has_display_name() {

From 4b615cb3a92fad0d65e8868408debbd82ca0f32e Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Tue, 16 Feb 2021 14:02:09 -0800
Subject: [PATCH 12/17] Clean email headers and warn on unsupported address
 format

Just in case, make sure CR or NL don't end up in
an email header.
---
 notify/smtp.sh | 55 +++++++++++++++++++++++++++-----------------------
 1 file changed, 30 insertions(+), 25 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index 43536cd2..42c1487c 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -53,16 +53,28 @@ smtp_send() {
   _saveaccountconf_mutable_default SMTP_BIN "$SMTP_BIN"
 
   SMTP_FROM="$(_readaccountconf_mutable_default SMTP_FROM)"
+  SMTP_FROM="$(_clean_email_header "$SMTP_FROM")"
   if [ -z "$SMTP_FROM" ]; then
     _err "You must define SMTP_FROM as the sender email address."
     return 1
   fi
+  if _email_has_display_name "$SMTP_FROM"; then
+    _err "SMTP_FROM must be only a simple email address (sender@example.com)."
+    _err "Change your SMTP_FROM='$SMTP_FROM' to remove the display name."
+    return 1
+  fi
   _debug SMTP_FROM "$SMTP_FROM"
   _saveaccountconf_mutable_default SMTP_FROM "$SMTP_FROM"
 
   SMTP_TO="$(_readaccountconf_mutable_default SMTP_TO)"
+  SMTP_TO="$(_clean_email_header "$SMTP_TO")"
   if [ -z "$SMTP_TO" ]; then
-    _err "You must define SMTP_TO as the recipient email address."
+    _err "You must define SMTP_TO as the recipient email address(es)."
+    return 1
+  fi
+  if _email_has_display_name "$SMTP_TO"; then
+    _err "SMTP_TO must be only simple email addresses (to@example.com,to2@example.com)."
+    _err "Change your SMTP_TO='$SMTP_TO' to remove the display name(s)."
     return 1
   fi
   _debug SMTP_TO "$SMTP_TO"
@@ -111,7 +123,7 @@ smtp_send() {
   _debug SMTP_TIMEOUT "$SMTP_TIMEOUT"
   _saveaccountconf_mutable_default SMTP_TIMEOUT "$SMTP_TIMEOUT" "$SMTP_TIMEOUT_DEFAULT"
 
-  SMTP_X_MAILER="${PROJECT_NAME} ${VER} --notify-hook smtp"
+  SMTP_X_MAILER="$(_clean_email_header "$PROJECT_NAME $VER --notify-hook smtp")"
 
   # Run with --debug 2 (or above) to echo the transcript of the SMTP session.
   # Careful: this may include SMTP_PASSWORD in plaintext!
@@ -121,6 +133,7 @@ smtp_send() {
     SMTP_SHOW_TRANSCRIPT=""
   fi
 
+  SMTP_SUBJECT=$(_clean_email_header "$SMTP_SUBJECT")
   _debug SMTP_SUBJECT "$SMTP_SUBJECT"
   _debug SMTP_CONTENT "$SMTP_CONTENT"
 
@@ -146,28 +159,26 @@ smtp_send() {
   return 0
 }
 
+# Strip CR and NL from text to prevent MIME header injection
+# text
+_clean_email_header() {
+  printf "%s" "$(echo "$1" | tr -d "\r\n")"
+}
+
+# Simple check for display name in an email address (< > or ")
+# email
+_email_has_display_name() {
+  _email="$1"
+  expr "$_email" : '^.*[<>"]' >/dev/null
+}
+
 ##
 ## curl smtp sending
 ##
 
 # Send the message via curl using SMTP_* variables
 _smtp_send_curl() {
-  # curl passes --mail-from and --mail-rcpt directly to the SMTP protocol without
-  # additional parsing, and SMTP requires addr-spec only (no display names).
-  # In the future, maybe try to parse the addr-spec out for curl args (non-trivial).
-  if _email_has_display_name "$SMTP_FROM"; then
-    _err "curl smtp only allows a simple email address in SMTP_FROM."
-    _err "Change your SMTP_FROM='$SMTP_FROM' to remove the display name."
-    return 1
-  fi
-  if _email_has_display_name "$SMTP_TO"; then
-    _err "curl smtp only allows simple email addresses in SMTP_TO."
-    _err "Change your SMTP_TO='$SMTP_TO' to remove the display name(s)."
-    return 1
-  fi
-
   # Build curl args in $@
-
   case "$SMTP_SECURE" in
   none)
     set -- --url "smtp://${SMTP_HOST}:${SMTP_PORT}"
@@ -219,7 +230,8 @@ _smtp_send_curl() {
   echo "$raw_message" | "$SMTP_BIN" "$@"
 }
 
-# Output an RFC-822 / RFC-5322 email message using SMTP_* variables
+# Output an RFC-822 / RFC-5322 email message using SMTP_* variables.
+# (This assumes variables have already been cleaned for use in email headers.)
 _smtp_raw_message() {
   echo "From: $SMTP_FROM"
   echo "To: $SMTP_TO"
@@ -259,13 +271,6 @@ _rfc2822_date() {
   LC_TIME="$_old_lc_time"
 }
 
-# Simple check for display name in an email address (< > or ")
-# email
-_email_has_display_name() {
-  _email="$1"
-  expr "$_email" : '^.*[<>"]' >/dev/null
-}
-
 ##
 ## Python smtp sending
 ##

From 5a182eddbf4ffafcc1b8a1b3757a49378f46af5f Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Tue, 16 Feb 2021 14:41:21 -0800
Subject: [PATCH 13/17] Clarify _readaccountconf_mutable_default

---
 notify/smtp.sh | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index 42c1487c..fabde79b 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -358,7 +358,7 @@ PYTHON
 #   - if MY_CONF is set _empty_, output $default_value
 #     (lets user `export MY_CONF=` to clear previous saved value
 #     and return to default, without user having to know default)
-#   - otherwise if _readaccountconf_mutable $name is non-empty, return that
+#   - otherwise if _readaccountconf_mutable MY_CONF is non-empty, return that
 #     (value of SAVED_MY_CONF from account.conf)
 #   - otherwise output $default_value
 _readaccountconf_mutable_default() {
@@ -366,8 +366,9 @@ _readaccountconf_mutable_default() {
   _default_value="$2"
 
   eval "_value=\"\$$_name\""
-  eval "_explicit_empty_value=\"\${${_name}+empty}\""
-  if [ -z "${_value}" ] && [ "${_explicit_empty_value:-}" != "empty" ]; then
+  eval "_name_is_set=\"\${${_name}+true}\""
+  # ($_name_is_set is "true" if $$_name is set to anything, including empty)
+  if [ -z "${_value}" ] && [ "${_name_is_set:-}" != "true" ]; then
     _value="$(_readaccountconf_mutable "$_name")"
   fi
   if [ -z "${_value}" ]; then

From 8f688e5e13b9cdc77134eb97dcc07435912dc4aa Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Wed, 17 Feb 2021 09:46:13 -0800
Subject: [PATCH 14/17] Add Date email header in Python implementation

---
 notify/smtp.sh | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index fabde79b..0c698631 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -287,6 +287,7 @@ try:
         from email.message import EmailMessage
     except ImportError:
         from email.mime.text import MIMEText as EmailMessage  # Python 2
+    from email.utils import formatdate as rfc2822_date
     from smtplib import SMTP, SMTP_SSL, SMTPException
     from socket import error as SocketError
 except ImportError as err:
@@ -318,6 +319,7 @@ except (AttributeError, TypeError):
 msg["Subject"] = subject
 msg["From"] = from_email
 msg["To"] = to_emails
+msg["Date"] = rfc2822_date(localtime=True)
 msg["X-Mailer"] = x_mailer
 
 smtp = None

From 28d9f00610b11254b43bf38d028524db859e588f Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Wed, 17 Feb 2021 09:57:44 -0800
Subject: [PATCH 15/17] Use email.policy.default in Python 3 implementation

Improves standards compatibility and utf-8 handling
in Python 3.3-3.8. (email.policy.default becomes the
default in Python 3.9.)
---
 notify/smtp.sh | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index 0c698631..69863206 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -285,8 +285,11 @@ _smtp_send_python() {
 try:
     try:
         from email.message import EmailMessage
+        from email.policy import default as email_policy_default
     except ImportError:
-        from email.mime.text import MIMEText as EmailMessage  # Python 2
+        # Python 2 (or < 3.3)
+        from email.mime.text import MIMEText as EmailMessage
+        email_policy_default = None
     from email.utils import formatdate as rfc2822_date
     from smtplib import SMTP, SMTP_SSL, SMTPException
     from socket import error as SocketError
@@ -311,7 +314,7 @@ subject="""$SMTP_SUBJECT"""
 content="""$SMTP_CONTENT"""
 
 try:
-    msg = EmailMessage()
+    msg = EmailMessage(policy=email_policy_default)
     msg.set_content(content)
 except (AttributeError, TypeError):
     # Python 2 MIMEText

From 6e49c4ffe006c45128c4ad8535e34e39b93901e2 Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Wed, 17 Feb 2021 10:02:14 -0800
Subject: [PATCH 16/17] Prefer Python to curl when both available

---
 notify/smtp.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index 69863206..71020818 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -15,7 +15,7 @@
 # SMTP_USERNAME=""  # set if SMTP server requires login
 # SMTP_PASSWORD=""  # set if SMTP server requires login
 # SMTP_TIMEOUT="30"  # seconds for SMTP operations to timeout
-# SMTP_BIN="/path/to/curl_or_python"  # default finds first of curl, python3, or python on PATH
+# SMTP_BIN="/path/to/python_or_curl"  # default finds first of python3, python2.7, python, pypy3, pypy, curl on PATH
 
 SMTP_SECURE_DEFAULT="none"
 SMTP_TIMEOUT_DEFAULT="30"
@@ -36,7 +36,7 @@ smtp_send() {
     # Look for a command that can communicate with an SMTP server.
     # (Please don't add sendmail, ssmtp, mutt, mail, or msmtp here.
     # Those are already handled by the "mail" notify hook.)
-    for cmd in curl python3 python2.7 python pypy3 pypy; do
+    for cmd in python3 python2.7 python pypy3 pypy curl; do
       if _exists "$cmd"; then
         SMTP_BIN="$cmd"
         break

From afe6f4030e9f7ec5c03146dd4dfe122d1ab7aab1 Mon Sep 17 00:00:00 2001
From: medmunds <medmunds@gmail.com>
Date: Wed, 17 Feb 2021 11:39:16 -0800
Subject: [PATCH 17/17] Change default SMTP_SECURE to "tls"

Secure by default. Also try to minimize configuration errors.
(Many ESPs/ISPs require STARTTLS, and most support it.)
---
 notify/smtp.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/notify/smtp.sh b/notify/smtp.sh
index 71020818..293c665e 100644
--- a/notify/smtp.sh
+++ b/notify/smtp.sh
@@ -11,13 +11,13 @@
 # SMTP_TO="to@example.com"  # required
 # SMTP_HOST="smtp.example.com"  # required
 # SMTP_PORT="25"  # defaults to 25, 465 or 587 depending on SMTP_SECURE
-# SMTP_SECURE="none"  # one of "none", "ssl" (implicit TLS, TLS Wrapper), "tls" (explicit TLS, STARTTLS)
+# SMTP_SECURE="tls"  # one of "none", "ssl" (implicit TLS, TLS Wrapper), "tls" (explicit TLS, STARTTLS)
 # SMTP_USERNAME=""  # set if SMTP server requires login
 # SMTP_PASSWORD=""  # set if SMTP server requires login
 # SMTP_TIMEOUT="30"  # seconds for SMTP operations to timeout
 # SMTP_BIN="/path/to/python_or_curl"  # default finds first of python3, python2.7, python, pypy3, pypy, curl on PATH
 
-SMTP_SECURE_DEFAULT="none"
+SMTP_SECURE_DEFAULT="tls"
 SMTP_TIMEOUT_DEFAULT="30"
 
 # subject content statuscode