The following script is run by this cron job:

# runs at 3:30am every day
30 3 * * * /backup/backup_db.sh

This script only does a few things. First, it creates a ‘filename’ variable consisting of ‘database_’ and then the date. Next it runs mysqldump on the database in question, outputting to /backup/$filename.sql. It sleeps for a bit (gzip didn’t seem to want to work immediately) and then compresses the .sql file into a more manageable size. From there, it opens a connection to an off-site server where I’ve got a ton of storage and bandwidth, and uses a server-to-server connection to transfer this gigantic file in a few minutes. Once that’s complete, it removes the file it created and waits until 3:30 the next morning to do it all over again.

#!/bin/sh
# Remember to chmod this file to 755 so it can be executed
filename="backup_"`eval date +%Y-%m-%d`
echo "Beginning MySQL dump."
mysqldump databasename --host=db.yourdomain.com --user=username --pass=password > /backup/$filename.sql
echo "MySQL dump complete. Beginning file compression."
sleep 3
gzip /backup/$filename.sql
echo "Compression complete. Beginning SCP transfer."
scp /backup/$filename.sql.gz username@offsitestorage.com:/home/username/backup
sleep 3
echo "File transfer complete. Cleaning up and exiting..."
rm /backup/$filename.sql.gz

To get the scp command to work without user input, you have to add the RSA key fingerprint to the list of known hosts. You can do this manually by editing the appropriate file, or you can do it the easy way: Open a terminal and SSH into your web server, and from that session, SSH into your backup server. You will get a warning claiming that “the authenticity of host … can’t be established — are you sure you want to continue connecting?”. Type “yes” and hit enter, and you will see a warning stating that this RSA key was added to the list of known hosts.

When your database backup is a 450MB file, you’ll find that space starts filling up quickly and the directory starts becoming needlessly cluttered. So again, we turn to crontab:

# database cleanup script; runs at 4am (the backup process only takes a few minutes)
0 4 * * * /home/username/db_backup/clean.php

…which dutifully executes the following cleanup script. This scans a directory for all files but itself, checks their ‘last-modified’ date against the current date and if it’s more than 7 days old, deletes them. This ensures that I’ve always got the most recent week’s worth of backups.

// /home/username/db_backup/clean.php
// If there are any files older than one week in this directory, nuke 'em
$dir = $_SERVER['DOCUMENT_ROOT'].'db_backup/';

/// Don't scan for yourself 
$script_name = pathinfo($_SERVER['SCRIPT_NAME']);
$script_name = $script_name['basename'];
$script_name = substr($script_name, 0, strrpos($script_name, '.'));

// Get your numbers straight
$time = mktime();
$one_week = 60 * 60 * 24 * 7;

// See how many backups already exist in this directory
$count = count(glob($dir."*.sql.gz"));

// Don't see them all? We should probably send an email...
if ($count < 7) {
	$to = 'my-email@my-domain.com';
	$subject = 'ERROR: SITE BACKUP FAILED!';
	$message = 'Deleted files have been detected. Check to assure script is running properly.';
	mail($to, $subject, $message);
	die();
// There's enough files? Trim them.
} else {
	if (is_dir($dir)) {
		if ($dh = opendir($dir)) {
			while (($file = readdir($dh)) !== false) {
				if ((substr($file, 0, 1) != '.') && (substr($file, 0, (strlen($script_name))) != $script_name) && (filetype($dir.$file) != 'dir')) {
					$filetime = filemtime($dir.$file);
					if (($time-$filetime) > $one_week) {
						unlink($dir.$file);
					}
				}
			}
			closedir($dh);
		}
	}
}

So, that’s it. Automated off-site MySQL backups using cron and PHP. Enjoy the peace of mind.

Also, if you’re using Firefox, you can make using this little script even easier. Right-click in the text-entry field and select the option “Add a Keyword for this Search” — The Name can be whatever you like, and I’ve found “link” to be a good value for the Keyword. Hit “Add” and you can use it right from your address bar. Prepending any location on the web with the word “link” will route that location to this script.

For example: “link http://www.google.com/intl/en_ALL/images/logo.gif” will take you to:

http://colinmccann.com/utility/linkerizer?url=http://www.google.com/intl/en_ALL/images/logo.gif

Enjoy. If you’ve got any suggestions as to how this could be improved, feel free to say so in the comments.

This is cool for a number of reasons. One, I don’t have to run an IMAP application on my phone; updates are pushed to me from an external source. Two, I don’t need a data plan to use it (although I may need to increase the number of texts I can receive without additional charges). Three, I can reply directly from my phone (although the message is received from a different address, depending on your carrier). Four, it’s got an accuracy of around one minute, and so far that has been more than adequate.

You need to create a web-writable file (chmod 755) called timestamp.txt in the same directory. I’ll include the cron script at the end of this post.

// filename: sms.php
$debug = false; // false = no output
$error = '';

// Define SMS parameters; your gateway may vary
$sms_to   = '4065551234@vtext.com';

// Define IMAP parameters
$imap_user = 'my.gmail.account';
$imap_pass = 'Secret-Password!';
$imap_host = '{imap.gmail.com:993/imap/ssl}INBOX';

// Define SMTP parameters
$smtp_host = 'smtp.mymailserver.com';
$smtp_port = '25';
$smtp_user = 'sms@mydomain.com'; // a valid user must exist
$smtp_pass = 'Another-Password!';

// Open a pointer to the mailbox
if ($debug) { $error = 'error: imap connection failed'; }
$imap = imap_open ($imap_host, $imap_user, $imap_pass) or die ($error);

// Quick exit
if (imap_num_msg ($imap) == 0) {
	imap_close ($imap);
	if ($debug) { $error = 'error: no messages in mailbox'; }
	die ($error);
}

// What was the last new message?
$old_timestamp = file_get_contents ('./timestamp.txt');

// Get last message
$msg_id = imap_num_msg ($imap);

// Gather IMAP message headers
$headers = imap_headerinfo ($imap, $msg_id);

// What's the timestamp on the most recent message?
$new_timestamp = $headers->udate;

// If it's the same message, get out of here.
if ($new_timestamp <= $old_timestamp) {
	imap_close ($imap);
	if ($debug) { $error = 'error: timestamp match'; }
	die ($error);
}

// Write timestamp of new message to external file
$handle = fopen ('timestamp.txt', 'w');
fwrite ($handle, $new_timestamp);
fclose ($handle);

// Let's look at that email we grabbed
$message = imap_get_message ($imap, $msg_id);

// Close IMAP Connection
imap_close ($imap);

// Okay, who's it from? Let's just do the email address...
// This needs cleaned up a bit; not all addresses include brackets.
$from = trim ($message['from']);
$b1 = strpos ($from, '<') + 1;
$b2 = strpos ($from, '>');
$from = substr ($from, $b1, ($b2 - $b1) );
// Here's an oddity -- gmail doesn't work. Go figure.
$from = str_replace ('gmail.com', 'g-mail.com', $from);

// And what's it say? Get rid of everything except alphanumerics and basic punctuation
$body = $message['body'];
$body = strip_tags ($body);
$body = preg_replace ('/[^A-Za-z0-9!-~]/', ' ', $body);
$body = preg_replace ('/\s\s+/', ' ', $body);

// Cut it off at 150 characters; seems to be the max for Verizon, anyway
$body = (strlen ($body) > 150) ? substr ($body, 0, 147).'...' : $body ;

// Set mail parameters; this sets the 'Return-Path' value
$param   = '-r '.$from;
$subject = '';
$headers = '';

// Send it off!
mail ($sms_to, $subject, $body, $headers, $param);

// IMAP message retrieval; returns a basic array
function imap_get_message ($imap_connection, $msg_no) {

	$header  = imap_header($imap_connection, $msg_no);
	$message = array();
	$message['subject'] = $header->subject;
	$message['from']    = $header->fromaddress;
	$message['to']      = $header->toaddress;
	$message['date']    = $header->date;

	$struct = imap_fetchstructure($imap_connection, $msg_no);
	@$parts = $struct->parts;
	$i = 0;

	if (!$parts) {
		$message['body'] = imap_body ($imap_connection, $msg_no);
	} else {
		$endwhile = false;

		$stack = array(); // Stack while parsing message
		$message['body'] = ''; // Content of message

		while (!$endwhile) {
			if (@!$parts[$i]) {
				if (count ($stack) > 0) {
					$parts = $stack[count ($stack) - 1]["p"];
					$i     = $stack[count ($stack) - 1]["i"] + 1;
					array_pop($stack);
				} else {
					$endwhile = true;
				}
			}

			if (!$endwhile) {
				// Create message part first (example '1.2.3')
				$partstring = '';
				foreach ($stack as $s) {
					$partstring .= ($s["i"]+1) . ".";
				}
				$partstring .= ($i+1);
				if (strtoupper ($parts[$i]->subtype) == "PLAIN") {
					$message['body'] .= imap_fetchbody ($imap_connection, $msg_no, $partstring); // Message
				}
			}

			if (@$parts[$i]->parts) {
				$stack[] = array("p" => $parts, "i" => $i);
				$parts = $parts[$i]->parts;
				$i = 0;
			} else {
				  $i++;
			}
		} // While loop
	}
	return $message;
}

Cron script:

# add to your crontab with 'crontab -e'
* * * * * /home/username/sms-gateway/sms.php

Before we get too far, feel free to grab this totally sweet icon to put in your totally sweet dock (or GnomeDo / Docky, if you can get it to work right):

Critical

AdBlock Plus
All-In-One Sidebar
AutoPager
Download Statusbar
PDF Download
Session Manager
Speed Dial
Tab Mix Plus

Webdev

Firebug
Linkchecker
Greasemonkey
ErrorZilla Mod
MeasureIt
HTML Validator

Communication

Gmail Manager
Blank Canvas Gmail Signatures
Delicious Bookmarks

Look n’ Feel

CustomizeGoogle
Locationbar²
Personal Menu
Yet Another Smooth Scrolling
FaviconizeTab

While I’m talking about it…

…does anyone out there know how to do a bulk add-on installation? All-In-One-Sidebar used to be able to do it, but now the Open dialog only lets you select a single file instead of multiple. This would turn the initial setup from a fifteen minute job into a sixty second job.

Greasemonkey Scripts

Wikipedia: Simple Research // a very clean and lightweight wikipedia skin
Gmail Air Skin 2 // takes gmail and makes everything better
Facebook Purity // Removes all ads and application messages

about:config settings

browser.urlbar.clickSelectsAll = true // first click on address bar highlights everything
security.dialog_enable_delay = 0 // removes countdown on extension installations
layout.word_select.stop_at_punctuation = true // double-click in address bar selects individual url segments

// I put this in my session class, as it's guaranteed to be called on each and every page
function is_admin() {
    $ip = array(
        file_get_contents('/secret/text/file.txt'),
        '123.45.678.90',
        );
    return (in_array($_SERVER['REMOTE_ADDR'], $ip));
}

So, what does it do? Simple. It checks to see if the IP address of the computer making the request is the same as the predefined IP address it’s got in 1) the hard-coded array and 2) the /secret/text/file.txt I’ve set up elsewhere on the site. What text file? Oh, yes, almost forgot.

This function worked great for a while, but one client in particular had an IP address that changed fairly rapidly. Every other week I’d get a request to change the embedded IP, and eventually I just got sick of it. The solution was the following:

// Save as /super/secret/ip/reset.php, or whatever suits your fancy.
$ip = $_SERVER['REMOTE_ADDR'];
$filename = '/secret/text/file.txt';
if (is_writable($filename)) {
    if (!$handle = fopen($filename, 'w')) {
        echo "Cannot open file ($filename)";
        exit;
    }
    if (fwrite($handle, $ip) === FALSE) {
        echo "Cannot write to file ($filename)";
        exit;
    }
    fclose($handle);
    header('Location: /');
    die();
} else {
    echo "The file $filename is not writable";
}

Now control was back in the clients’ hands. Each time their IP changes, they just click a bookmark that accesses the above script. It opens the aforementioned text file, grabs the current IP address, and writes a single line of text. This is followed immediately by a redirect to home (/), but you could just as easily have it point anywhere.

So, now the function works. How do you use it? The short answer would be “everywhere” — at least, that’s been my experience:

if (is_admin()) {
    echo 'content that only admins can see';
} else {
    echo 'content that everyone else sees';
}

This can be used anywhere you want to make changes to a site, but leave everything completely intact for anyone that’s not on your VIP list. I’ve managed to complete some pretty extensive modifications by simply wrapping everything I was working on in this function. Clients love it because they can see changes and know that customers aren’t seeing development in progress. As for the amount of time I’ve saved by not hassling with copying files, making changes, reuploading, renaming, etc., well, it’s safe to say that I’m never going back to the old ways.

edit 2/8/10:

For quick deployment, this can be easily memorized and typed in about ten seconds:

function is_admin() {
    return ($_SERVER['REMOTE_ADDR'] == '123.45.678.90');
}