Enviar e-mails con adjuntos desde la terminal con sendmail [Bash script]

#!/bin/bash

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# gemail.sh  Copyright (C) 2014  Gaspar Fernández <gaspar.fernandez@totaki.com>

# This bash script will help you to use sendmail allowing us to send e-mails from
# the terminal in a friendly way just say destination, subject and body in the command
# arguments. It allows us also to send mail attachments with local files and allows you
# to use internal sendmail application or connection to a SMTP server.
#
# I find it interesting when using remotely a server with SSH and I must send a file
# located in it to someone. I wrote this little script to send the file directly to
# the destination.

# Changelog:
# - 20160902: Fixed bad python indentation (after yesterday's re-indentation)
# - 20160901: Fix selecting SMTP user
#             Fix when sending mails through cron jobs (again) this time,
#             when sending from scripts ran in cron jobs. /dev/stdin is
#             present in some conditions but with no data.
#             Indentation fix
# - 20160706: Several new CLI options.
# - 20160705: Added SMTP support with tiny python script
# - 20160703: Fixes adding headers and autoheaders
# - 20160415: Fix sending mails through cron job. Must check permissions over /dev/stdin
# - 20150216: Allow body to be read from stdin
# - 20150210: Bug fix separate recipient and non-recipient headers (for some reason some
#             mailers didn't do it right when they are mixed.
# - 20150210: Added SENDMAIL_BASIC_ARGS to call sendmail -t and allow more recipients
# - 20150113: Bug fix (sendmail with no arguments)
# - 20141212: Preview mode and additional sendmail find
# - 20141211: Removed extra \n when no extra headers
# - 20141208: Allows us to send many attachments
# - 20141206: Code clean up
# - 20141129: Initial idea of the script and wrote basic functionality

# To do:
#  - Doc and examples !!!

VERSION="0.8"
#MAIL_BOUNDARY="m41lb0und4ry"       # We can randomize it later
MAIL_BOUNDARY=`cat /dev/urandom | tr -dc 'a-zA-Z0-9' | head -c 40`
SENDMAIL_COMMAND=`which sendmail`
# Read recipients from mail (to use CC and so)
SENDMAIL_BASIC_ARGS="-t"
SENDMAIL_COMMAND="";
SMTP_DEFAULT_SECURITY="starttls"
_MYNAME=$0

function showUsage()
{
    # We must extend this help to use headers and so
    if [ -n "$1" ]
    then
        echo "Sorry: $1"
        echo
    fi
    echo "gemail.sh Version $VERSION"
    echo "Sends e-mails from terminal the easy way. (https://github.com/gasparfm/gscripts)"
    echo
    echo "Use:"
    echo "  $_MYNAME [options] [destination] [subject] [body] [attachment1] [attachment2] ... [attachmentN]"
    echo
    echo "or:"
    echo
    echo "  $_MYNAME [options] [destination] [subject] [attachment1] [attachment2] ... [attachmentN] < bodyfile"
    echo
    echo "These are the supported options:"
    echo " -t, --to=destination     : Adds to recipient to the e-mail (if this option is"
    echo "                present you can dismiss [destination] argument)."
    echo " -f, --from=origin    : This is YOUR e-mail."
    echo " -s, --subject=subject    : The subject of your message. (if this option is "
    echo "                present you can dismiss [subject] argument)."
    echo " -b, --body=message   : This is yout message. (if this option is present,"
    echo "                you can dismiss [body] argument)."
    echo " -p, --preview        : Don't send the message, just preview the e-mail."
    echo " -h, --header=content : Adds new header to the e-mail. Allowed headers are:"
    echo "                From, CC, BCC, Reply-to, Date, Organization, "
    echo "                X-Mailer and Message-Id."
    echo " -a, --attach=file    : Attaches this file to the e-mail."
    echo " -e, --smtp=conn_str  : Gives SMTP server or connection string."
    echo "            This connection string can be: "
    echo "              * server hostname or IP"
    echo "              * user:password@server (if user or password has :"
    echo "                 or @ characters they may be escaped.)"
    echo " -u, --smtp-user=user : Sets SMTP server user."
    echo " -w, --smtp-pass=passwd   : Sets SMTP server password."
    echo " -n, --noautoheaders  : Disables gemail.sh automatic headers."
    echo
    echo "You can also insert some more headers after the attachments:"
    echo "  "From: me@email.ext" or "From: Me <me@myself.ext>" to specify my email"
    echo "  "CC: my@email.ext" or "CC: My friend <my@friend.ext>" for carbon copy"
    echo "  "BCC: my@email.ext" or "BCC: My friend <my@friend.ext>" for blind carbon copy"
    echo "  "Reply-to: another@email.com" for a new reply-to address";
    echo "  Another headers accepted: Date, Organization, X-Mailer, Message-Id"
    echo
    echo "You can use the keyword *preview* to print the command to be executed (if you have attached files the output can be large)"
    exit
}

function findSendmail()
{
    # Try to find again sendmail in extra paths not in $PATH
    EXTRAPATHS=("/usr/sbin/" "/sbin/" "/usr/local/sbin/" "$HOME/.local/bin/")

    for p in "${EXTRAPATHS[@]}";
    do
        if [ -x "${p}sendmail" ]
        then
            echo "${p}sendmail"
            return
        fi
    done
}

function test_py()
{
    if [ -z "$(which python)" ]
    then
        echo "Python not found"
        return;
    fi

    python <<EOF
try:
    import smtplib
except ImportError as er:
        print er
EOF
}

function pysmtp()
{
    TO="$1"
    while read line
    do
        echo "$line"
    done | python <(cat <<EOF
import smtplib
import sys
try:
    smtpObj = smtplib.SMTP('$SMTP_SERVER')
    if ('$SMTP_SECURITY' == 'starttls'):
        smtpObj.starttls()
    if ('$SMTP_USER'):
        smtpObj.login('$SMTP_USER', '$SMTP_PASS')
    message = sys.stdin.read()
    _from = message.find('From:')
    fromstr = 'root'
    if _from != -1:
        fromstr = message[_from+5:message.find('\n', _from)]
    smtpObj.sendmail(fromstr.strip(), '$_TO', message)
except Exception as e:
    print e
EOF
    )
}

function callsend()
{
    _TO="$1"
    _PREVIEW=$2
    if (( $_PREVIEW==1 ))
    then
        cat
    elif [ $SENDER = "sendmail" ]
    then
        if [ -z "$SENDMAIL_COMMAND" ];
        then
            echo "No sendmail found in your PATH. Make sure you have it!"
            exit 1;
        fi
        $SENDMAIL_COMMAND $SENDMAIL_BASIC_ARGS "$_TO"
    elif [ $SENDER = "smtp" ]
    then
        PYERR="$(test_py)"
        if [ -n "$PYERR" ]
        then
            echo "Python error: $PYERR"
            exit 1;
        fi
        RESPONSE="$(pysmtp "$TO")"
        if [ -n "$RESPONSE" ]
        then
            echo "Error sending via SMTP: $RESPONSE"
            return 1;
        fi
    fi
}

function add_attachment()
{
    ATTACH="$1"
    ATTACH_MIME=`file --mime-type -b "$ATTACH"`
    ATTACH_NAME=`basename "$ATTACH"`
    ATTACH_BASE64=`base64 "$ATTACH"`
    ATTACHMENTS="$ATTACHMENTS
--$MAIL_BOUNDARY
Content-Type: $ATTACH_MIME; name="$ATTACH_NAME"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="$ATTACH_NAME"

$ATTACH_BASE64"
}

function add_header()
{
    HEADERINFO="$1"
    OLDIFS=$IFS
    IFS=":"
    read -a HEADER <<< "$HEADERINFO"
    IFS=$OLDIFS
    case ${HEADER[0]} in
        # Separating headers for some mail systems
        "From" | "Reply-to" | "CC" | "BCC" )
            if [ "${HEADER[0]}" = "From" ] || [ "${HEADER[0]}" = "Reply-to" ]
            then
                RECIPIENTS="$(echo -e "$RECIPIENTS" | grep -v "${HEADER[0]}:")"
            fi

            if [ -z "$RECIPIENTS" ]
            then
                RECIPIENTS=$HEADERINFO
            else
                RECIPIENTS="`echo -e "$RECIPIENTS""\n""$HEADERINFO"`"
            fi
            ;;
        "Date" | "X-Mailer" | "Organization" | "Message-Id" )
            MOREHEADERS="$(echo -e "$MOREHEADERS" | grep -v "${HEADER[0]}:")"
            if [ -z "$MOREHEADERS" ]
            then
                MOREHEADERS=$HEADERINFO
            else
                MOREHEADERS="`echo -e "$MOREHEADERS""\n""$HEADERINFO"`"
            fi
            ;;
        "preview")
            PREVIEW=1
            ;;
        *)
            showUsage "Attachment $HEADERINFO not found"
    esac
}

function add_auto_headers()
{
    if [ "$AUTOHEADERS" = "yes" ]
    then
        if [ -z "$(grep "From:" <<< $RECIPIENTS)" ]
        then
            add_header "From: $(echo `whoami`@`hostname`)"
        fi

        if [ -z "$(grep "Date: " <<< $MOREHEADERS)" ]
        then
            add_header "Date: $(date -R) ($(date +%Z))"
        fi

        if [ -z "$(grep "Message-Id: " <<< $MOREHEADERS)" ]
        then
            _FROM=$(grep "From:" <<< $RECIPIENTS)
            add_header "Message-Id: <"$(uuidgen | awk -F'-' -v date=$(date +%Y%m%d%H%M%S) -v at=$(echo $_FROM | cut -d'@' -f2) '{print $1$2"."date"."$3$4"@"at}')">"
        fi
        if [ -z "$(grep "X-Mailer: " <<< $MOREHEADERS)" ]
        then
            add_header "X-Mailer: gemail.sh Ver. $VERSION"
        fi
    fi
}

function smtp_settings()
{
    STS="$1"

    OLDIFS=$IFS
    IFS=$(echo -e "\n")
    while read user
    do
        read pass
        read server
        break
    done <<< $(sed -r 's/([^\:\@]*(\\:[^\:\@]*)*):([^\@]*(\\@[^\:\@]*)*)@([^\/\:]*)/\1\n\3\n\5/' <<< "$STS");
    if [ -z "$user" ]
    then
        showUsage "Wrong SMTP server string: "$STS""
    fi
    SENDER="smtp"
    if [ -z "$pass" ] && [ -z "$server" ]
    then
        # We only have server
        SMTP_SERVER="$user"
    else
        SMTP_SERVER="$server"
        SMTP_USER="$user"
        SMTP_PASS="$pass"
    fi
    SMTP_SECURITY=$SMTP_DEFAULT_SECURITY
}

# Fill missing headers automatically
AUTOHEADERS="yes"
ATTACHMENTS=""
MOREHEADERS=""
RECIPIENTS=""

# By default, no PREVIEW
PREVIEW=0

# By default, sent by sendmail
SENDER="sendmail"

# Parse input arguments
ARGS=$(getopt -q -o "t:f:s:b:ph:a:e:u:w:n" -l "to:,from:,subject:,body:,preview,header:,attach:,smtp:,smtp-user:,smtp-pass:,noautoheaders" -n "gemail.sh" -- "$@");
if [ $? -ne 0 ];
then
    showUsage "Error parsing arguments"
fi

eval set -- "$ARGS";

while [ $# -gt 0 ]; do
    case "$1" in
        -t|--to)
            TO="$2"
            shift;
            ;;
        -f|--from)
            add_header "From: $2"
            shift;
            ;;
        -s|--subject)
            SUBJECT="$2"
            shift;
            ;;
        -b|--body)
            BODY="$3"
            shift;
            ;;
        -p|--preview)
            PREVIEW=1
            ;;
        -h|--header)
            add_header "$2"
            shift;
            ;;
        -a|--attach)
            add_attachment "$2"
            shift;
            ;;
        -e|--smtp)
            smtp_settings "$2"
            shift;
            ;;
        -u|--smtp-user)
            SMTP_USER="$2"
            shift
            ;;
        -w|--smtp-pass)
            SMTP_PASS="$2"
            shift
            ;;

        -n|--noautoheaders)
            AUTOHEADERS="no"
            ;;
        --)
            shift;
            break;
            ;;
        *)
            echo "Unrecognised option "$1""
            showUsage
    esac
    shift;
done
if [ -n "$1" ] && [ -z "$TO" ]
then
    TO="$1"
    shift
fi

if [ -n "$1" ] && [ -z "$SUBJECT" ]
then
    SUBJECT="$1"
    shift
fi

# If we have data in /dev/stdin pick up the email body from /dev/stdin
# -t 0 : make sure stdin (fd=0) is not a terminal as this program is not
# interactive
if [ -r /dev/stdin ] && [ ! -t 0 ]
then
    BODY=$(cat /dev/stdin)
fi
# If we have no body yet, test the argument. In cron jobs /dev/stdin may
# be detected with no data.
if [ -n "$1" ] && [ -z "$BODY" ]
then
    BODY="$1"
    shift
fi

# Additional sendmail find if not in PATH
if [ -z "$SENDMAIL_COMMAND" ];
then
    SENDMAIL_COMMAND=`findSendmail`
fi

# Fill attachments and additional user headers
while [ $# -gt 0 ]
do
    ATTACH="$1"
    if [ ! -r "$ATTACH" ];
    then
        # Not an attachment, ok but it can be an additional header it will have : let's check it
        add_header "$ATTACH"
    else
        add_attachment "$ATTACH"
    fi
    shift
done

if [ -z "$TO" ]
then
    showUsage "No recipient found."
elif [ -z "$SUBJECT" ]
then
    showUsage "No subject found."
elif [ -z "$BODY" ]
then
    showUsage "No body found."
fi

# echo "TO: $TO"
# echo "SUBJECT: $SUBJECT"
# echo "BODY: $BODY"

add_auto_headers

# Send message
( echo "To: $TO";
    if [ -n "$RECIPIENTS" ]; then
        echo -e "$RECIPIENTS"
    fi
    echo "Subject: $SUBJECT";
    if [ -n "$MOREHEADERS" ]; then
        echo -e "$MOREHEADERS"
    fi
    echo "MIME-Version: 1.0";
    echo "Content-Type: multipart/mixed; boundary="$MAIL_BOUNDARY"";
    echo -e "\n"
    echo "--"$MAIL_BOUNDARY;
    echo "Content-Type: text/plain";
    echo -e "Content-Disposition: inline\n";
    echo "$BODY";
    echo -e "$ATTACHMENTS"
    echo "--"$MAIL_BOUNDARY"--") | callsend $TO $PREVIEW

RESULT=$?
if (( $RESULT==0 ))
then
    echo "Message sent successfully";
else
    echo "Could not send message"
fi