In doing some optimizing for phpVMS, I noticed I have a lot of HTTP requests:

As you can see, there are 27 HTTP requests, 15 of them JavaScript files. This means, the browser has to reach out 15 times to grab individual JS files. This seems like a straight forward problem, if we can just condense those 15 files into one, then we can almost half the number of total requests.

So we can do this manually – copy and paste each file, into one master file. The problem is, when you update one file, you have to go and search around in your other files, and figure out exactly where to update, or just redo the entire condensing process. It’s a pain. but these seems like a good place to write some code to do it.

As part of Codon now, I’ve included a class called CodonCondenser. It’s just a basic class that will condense requested files into one file. I set out some requirements:

1. It’s a class, so we can reuse it
2. Use it for any file types
3. Have a cached file of our condensed batch, so we don’t need to dynamically condense it every time, which could be expense.
4. Be able to add/remove files at will, and it will handle that

Since we have some basic requirements, let’s plan how it’ll work:

1. Set our options, the path to the files, the URL to the files since our function will return the URL to the generated file, set the file type, and a cache
2. Pass an array, with the list of our files
3. Generate a MD5 hash of the array we’ve passed, this will be our file name. If the array changes, as in we add files, or remove files, the hash will change, so we satisfy requirement #4… OR… use a filename that we generate, or pass in.
4. Check this file name, see if it exists; if it does, see if the file age is older than we want (satisfying #3). If it’s not too old, then use this file
5. If it’s too old, or doesn’t exist, then generate a new condensed file and return the URL to it.

So let’s start:

class CodonCondenser
{
	public $path;
	public $url;
	public $timeout = 24;
	public $file_ext = '';
	public $filename;
}

Our basic class, with the settings. Next is our function to set these options:

public function SetOptions($path, $url, $file_ext, $timeout=24)
{
	$this->path = $path;
	$this->url = $url;
	$this->timeout = $timeout;
	$this->file_ext = $file_ext;
}

We pass the $path, which is the absolute path to the files, and $url, which is the path to where the file is will be publicly accessible.

$file_ext is the extension of the condensed file (js, css, htm, etc), and $timeout is the time that the condensed file is considered ‘fresh’. Passing this as blank ($timeout=’’), will disable the time check.

Next is our function to check the cached version. We’ll return true or false if the file passed is valid:

protected function getCachedFile()
{
	if(!file_exists($this->path.'/'.$this->filename))
	{
		return false;
	}

	# Check if the version that exists
	#    is older than the timeout we have alloted
	# Value of "" skips the time check
	if($this->timeout == '')
	{
		if ((time() - @filemtime($file)) > ($this->timeout*3600))
		{
			# It is older, so delete it
			@unlink($this->path.'/'.$file);
			return false;
		}
	}

	# The cache file is ok
	return true;
}

So what we are checking, if the file doesn’t exist, then return false. Next, if the timeout value is blank, just skip the check, and only base it on whether the condensed file exists or not (as we saw the option up above). Otherwise, we check the modification time of the file, and if the current time – the time file created (in seconds), is greater than our timeout value, then return false. If we have 0 (zero) as a timeout value, it will generate a new file every time.

Note that the function is protected, so we can’t access it directly, and instead, go through the main function:

public function GetCondensedFile($files, $filename='')
{
	if($filename != '')
	{
		$this->filename = $filename;
	}
	else
	{
		$this->filename = md5(implode('',$files));
		$this->filename .= '.'.$this->file_ext;
	}
}

First, here we are checking if we passed an optional filename. I use the filename option, depending on whether it’s being used in the admin area, or in the front-end client area. I’ll explain this later.

Otherwise, we will build a filename, we check for the cached file, using the function above:

# Check if we've already made this condensed cache file
#    If we have, then just give the URL of that file
if($this->getCachedFile() == true)
{
	return $this->url.'/'.$this->filename;
}

If the getCachedFile() returns true, that mean’s that the cached file is okay, and we exit and just return the full URL path to the condensed file. If it’s not condensed, then we build our condensed file:

$fp = fopen($this->path.'/'.$this->filename, 'w');

foreach($files as $file)
{
	fwrite($fp, file_get_contents($this->path.'/'.$file));
}

fclose($fp);
return $this->url.'/'.$this->filename;

This is pretty straightforward, we just open the condensed file, and write every file into it, then return the full URL path to the file. So this is how we’ll use it:

$condenser->SetOptions('/var/www/lib/js', 'http://mysite.com/lib/js', 'js');

$files = array( 'jquery.min.js', 'jquery-ui.js',
				'jquery.dimensions.pack.js',
				'jquery.form.js', 'jqModal.js',
				'jquery.bigiframe.js',
				'jquery.sparklines.js',
				'jquery.autocomplete.js',
				'jquery.tablesorter.pack.js',
				'jquery.tablesorter.pager.js',
				'jquery.metadata.js', 'jquery.impromptu.js',
				'jquery.listen-min.js', 'nicEdit.js');

$url = $condenser->GetCondensedFile($files);

And then to link the Javascript into our page:

<script type="text/javascript" src="<?php echo $url?>"></script>

Our result in the end:

14 less requests! Almost half the number of requests. Woohoo! While it’s a basic class, and we can certainly expand it by adding features such as compression (such as implementing JSMin-PHP into), to minify and pack the JS. Be careful if your JS files are already packed if you re-pack them, it could cause errors. I use files that have already been packed, and merge them together this way.

You can also use this for HTML files, CSS, any other text files which are all brought in together in separate requests.

Click to download the full script.

I just did a quick thing for the phpVMS admin panel, displaying random quotes from the movie Airplane! in the footer. Just call the function randquote(), and it’ll return the string, so you can do whatever you want with it.

And don’t call me Shirly…

Click to download it (zip file)

Found an old post I wrote, about the new “MySQLi” functions in PHP 5+. PHP6 is almost on the horizon, and I personally haven’t seen too much wide adoption of this new MySQL functionality.

The i in “MySQLi” stands for i”mproved”. While most of the functions between MySQL and MySQLi will work exactly the same (just by replacing the mysql_ with mysqli such as mysqli_query()), there are several cool things that come with this new "improved" MySQL library. One thing that’s available is to use the database connector itself as a "class", making it easy to create your own database library that is customized to your application. This makes it real easy to separate the logic and extend your database code, for those of us who are OO nuts

Another advantage is that you can also use an SSL connection easily with the database, without jumping through hoops by just providing the path to the certificate. But the best improvement is the ability to use prepared statements. This makes queries (more) secure by telling MySQL exactly which types of values to expect, and also stores a template of those values in memory. The result is security, and since it’s cached, it ends up being much faster on repeat queries and inserts.

I will use the procedural version of the code in these examples, to keep it a bit easier, and I’m also leaving out error checking, for the sake of example.

//First we create our connection
$db_link = mysqli_connect('localhost', 'username', 'password', 'db name');

//Now we want to prepare our statement
// So we first have to initialize it.
//Now we prepare the actual statement. The ? replace the variables
// We're going to "insert" those later on
mysqli_stmt_prepare($db_link, 'SELECT * FROM data WHERE stringvalue=? AND numbervalue=?');

So we’re prepared the statement, putting in question marks where there are going to be values placed in. We are “binding” a value into there, so we have to use a function mysqli_stmt_bind_param().  If we look at the parameters for this function, it is:

mysqli_stmt_bind_param(statement, types, variables);

The types, are defined as:

• i – integer (any whole number)
• d – double (number, with decimals)
• s – string
• b – blob

Since we have to variables in the query above (string value and number value), our "types" are going to be "si". The first is a string (s) and the second is a number (i).

mysql_stmt_bind_param($statement, 'si', $string_value, $number_value);

You might be wondering “What’s the point?”. It helps a great deal with security, when it comes to inserting data:

$statement = mysqli_prepare($link, 'INSERT INTO table (name, idnumber, address) VALUES (?, ?, ?)');

mysqli_stmt_bind_param($statement, 'sis', $name, $idnumber, $address);

$name = 'First Last';
$idnumber = 123456789;
$address = 'I live here';

mysqli_stmt_execute($statement);
mysqli_stmt_close($statement);

As you can see, MySQL is now expecting certain types for the data which is being inserted, and treats it as such – strings as strings, integers as integers, and so on, and will automatically take the best precautions to ensure the data is valid.

For more info, check out the Zend information on MySQLi.