#!/usr/local/bin/php
#
# Manda un correo a la/s dirección/es indicada/s si determina que el
# server monitorizado está offline.
#

<?php

// Some global vars...
$LOG = True;
$link = "http://a.website.to.monitor/";
$retries = 0;
$logfile = "/var/log/mail_through_socks.log";

/* function webtest() - Comprueba si puede leer de una web dada. */
function webtest() {

    global $LOG, $link, $logfile;
    $online = True;

    $fd = @fopen($link,'r');
    $byte_leido = @fread($fd, 1);
    fclose($fd);

    if(!$byte_leido)
        $online=False;
    else
        if ($LOG) system("echo 'Site link ".$link." seems OK.' >> ".$logfile);

    return $online;
}

/* function correo() - Manda un correo a una cuenta dada a través de un SMTP.  */
function correo() {

    // Vars.
    global $LOG, $link, $logfile;
    $mailServer = "smtp.server";
    $mailPort = "25";
    $user = "username";
    $pass = "password";

    // Connection with the SMTP server...
    $mail_handle = fsockopen($mailServer, $mailPort); // Open a socket.

    if(!$mail_handle) {
        system("echo 'Connection to SMTP failed! Exiting...' >> ".$logfile);
        exit();
    } else {

        if($LOG){
            system("echo 'Connected to SMTP...' >> ".$logfile);
            $tmp = fgets($mail_handle, 1024);
            system("echo ".$tmp." >> ".$logfile);
        }

		        fputs($mail_handle, "HELO PC\n");
        if($LOG){
            $tmp = fgets($mail_handle, 1024);
            system("echo '".$tmp."' >> ".$logfile);
        }
        sleep(1);

        // Autenticación (en base64 por defecto).
        fputs($mail_handle, "AUTH LOGIN\n");
        $tmp = fgets($mail_handle, 1024);
        if($LOG) system("echo '".$tmp."' >> ".$logfile);
        sleep(2);

        fputs($mail_handle, base64_encode($user)."\n");
        sleep(2);

        fputs($mail_handle, base64_encode($pass)."\n");
        sleep(2);

        fputs($mail_handle, "MAIL FROM: sender@someplace.com\n");
        if($LOG){
            $tmp = fgets($mail_handle, 1024);
            system("echo '".$tmp."' >> ".$logfile);
        }
        sleep(1);

		// Repetir este bloque para cada destinatario... o hacer un bucle :)
        fputs($mail_handle, "RCPT TO: receipt@someplace.com\n");
        if($LOG){
            $tmp = fgets($mail_handle, 1024);
            system("echo '".$tmp."' >> ".$logfile);
        }
        sleep(1);
		
        fputs($mail_handle, "DATA\n");
        if($LOG){
            $tmp = fgets($mail_handle, 1024);
            system("echo '".$tmp."' >> ".$logfile);
        }
        sleep(1);

        fputs($mail_handle, "Subject: Site ".$link." seems down!!!!\n");
        fputs($mail_handle, "From: Web Watchbot\n");
        fputs($mail_handle, "\nSite ".$link." seems down!!!!\n");
        fputs($mail_handle, "\r\n.\r\n");
        if($LOG){
            $tmp = fgets($mail_handle, 1024);
            system("echo '".$tmp."' >> ".$logfile);
        }
        sleep(1);

		        fputs($mail_handle, "QUIT\n");
        if($LOG){
            $tmp = fgets($mail_handle, 1024);
            system("echo '".$tmp."' >> ".$logfile);
        }

        system("echo '...done!' >> ".$logfile);
    }
}

/* function main() - Ejecuta el código principal (MAIN). */
function mein() {

    global $retries, $LOG, $link, $logfile;

    // Mensajería de fecha inicial...
    system("echo '' >> ".$logfile);
    system("echo `date -u` >> ".$logfile);

    // A la 4ª va la vencida.
    while(!webtest()){
        $retries++;

        if($retries==1){
            if($LOG){
                system("echo 'Site link '".$link."' seems down!!' >> ".$logfile);
                system("echo 'Sleeping 60secs before retry... 2 tries left.' >> ".$logfile);
            }
            sleep(60); // 1min (60")
        } else if($retries==2){
            if($LOG) system("echo 'Sleeping 5min before retry... 1 try left!' >> ".$logfile);
            sleep(300); // 5min (300")
        } else if($retries==3){
            if($LOG) system("echo 'Sleeping 10min before retry... Last try!!!' >> ".$logfile);
            sleep(600); // 10min (600")
        } else {
            correo();
            $retries=0;
            exit();
        }
    }
}

mein();

?>