PHP by Book

Here’s how PHP developer declare a string, which is something very common in any programming language.

$my_var = 'hello world';
// or
$my_var = "hello world";

PHP Tricks

What if you do the following:

echo hello;

That appears to be correct … Well, it’s not absolutely correct. You’ll be “noticed”.

// Notice: Use of undefined constant hello
echo hello;

However if you disable error reporting, the code will be completely fine.

error_reporting(0);

// no problem now
echo hello;

Variations

What follows from the thing above is that you can use strings without quotes:

// hello
echo hello;

// hello world (concatenated)
echo hello . ' world';

// helloworld
echo hello . world;

However you can’t have spaces and most of the “special” symbols.

// syntax error
echo hello world;

// syntax error
echo hello!;

Final Words

Although you can do this in PHP, that is completely wrong. The code becomes more difficult to read and understand. In the second place you can miss a $ sign in front of a variable declaration and thus the PHP interpreter will assume this is a string. So disable error reporting isn’t so great sometimes.

The caching is not a process invented in the last year, it’s useless to describe why do you need it, but however my intention is to describe how to make it work with Zend Framework.

The docs page of Zend_Cache is pretty clear about everything and I’ll describe the most important part of the cache setup.

First setup the cache back and frontend options. You need to decide where to save the cache files, how to cache them, and what lifetime do they need.

The most used cache configuration is, as you may guess, this one described into the doc page. Setup the front and backend options is just as simple as:

$frontendOptions = array(
     'lifetime' => 7200, // cache lifetime of 2 hours
     'automatic_serialization' => true
);

$backendOptions = array(
   'cache_dir' => './tmp/'
   // Directory where to put the cache files
);

// getting a Zend_Cache_Core object
$cache = Zend_Cache::factory('Core',
                             'File',
                              $frontendOptions,
                              $backendOptions);

Because all this is well described into the doc page, which you can found here I won’t talk about it. But I’ll talk only about one sole thing. How much the cache must live? What should be its lifetime.

The answer is simple. If you have some basic statistic of your site traffic and you don’t change much the data you can prefer longer cache period. But imagine the site’s making 1000 visits per minute! Than even if you cache every minute and the cache expires every minute will be a success and the user perception will be really great. From those 1000 visitors only few will wait until the cache’s built and the other hundreds will receive really fast response!

Be careful when you cache only because you can overflow the directory where you cache, which will be difficult though.

In other way many people are thinking about Zend Optimizer and its work with Zend_Cache. These are really different things. Zend Optimizer has nothing to do with your code it is a PHP caching tool. As you may know PHP interpreter mingles the code into “machine like” code, which in turn can be cached into the RAM with the help of Zend Optimizer. Checkout more here.