This guide will explain how to install the memcached system, including the PHP extension, on Mac OS X 10.6.

Xcode

The Xcode package installs the necessary versions of tools like autoconf which is needed during the PHP extension compilation process. Make sure you have Xcode 3.2 installed; the install package is available on the Snow Leopard install DVD under the “Optional Installs” folder.

libevent

libevent is a pre-requisite for memcached.

• cd /tmp; curl -O http://www.monkey.org/~provos/libevent-1.4.12-stable.tar.gz
• tar zxvf libevent-1.4.12-stable.tar.gz
• cd libevent-1.4.12-stable
• ./configure; make
• sudo make install

memcached

memcached is the daemon responsible for actually storing and retrieving arbitrary objects for your applications.

• cd /tmp; curl -O http://memcached.googlecode.com/files/memcached-1.4.1.tar.gz
• tar zxvf memcached-1.4.1.tar.gz
• cd memcached-1.4.1
• ./configure; make
• sudo make install

libmemcached

libmemcached is the shared library that will allow clients, in this case PHP, access the memcached daemon.

• Download libmemcached, move to /tmp and unpack
• cd libmemcached-0.31
• ./configure; make
• sudo make install

php extension

Now we are ready to prepare the PHP extension to memcached, which is available from pecl.

• cd /tmp; pecl download memcached
• gzip -d < memcached-1.0.0.tgz | tar -xvf -
• cd memcached-1.0.0; phpize

You should see output similar to the following:

Configuring for:
PHP Api Version: 20090626
Zend Module Api No: 20090626
Zend Extension Api No: 220090626


• ./configure; make
• sudo make install

On a successful install, you will get the following message:

Installing shared extensions: /usr/lib/php/extensions/no-debug-non-zts-20090626/

Modify your php.ini configuration file and make sure you have the following line included:

extension = memcached.so

You can then restart your Apache server:

• sudo apachectl restart

to make the memcached functionality available in your scripts.

References

• Compiling shared PECL extensions with phpize
• PHP: Memcached - Manual

Warning: getdate() [function.getdate]: It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'Europe/London' for 'BST/1.0/DST' instead in /Users/gscott/Sites/hello-world.php on line 9

The solution is to edit (or create, if it doesn’t exist) /private/etc/php.ini and make sure a setting exists for date.timezone. For example:

date.timezone = Europe/London

After making the change, restart Apache

sudo apachectl restart

• List of supported timezones.

The Good: Closures

Anonymous functions created with create_function have always been a bit messy. With 5.3 comes support for closures with a much cleaner syntax:

    $greet = function($name)
    {
        printf("Hello %s\r\n", $name);
    };

    $greet('World');
    $greet('PHP');

The Bad: Backwards incompatible changes

Although not a massive change from 5.2, there are enough differences to break existing code.

The Ugly: Namespaces

There has been quite a discussion about PHP’s new namespace syntax.

$c = new \my\name\MyClass;

It’s just damn ugly. The more sensible choice, :: is already used as the scope resolution operator and was therefore dismissed.

PHP Warning: PHP Startup: Unable to load dynamic library './mcrypt.so' - (null) in Unknown on line 0

mcrypt is a good example of a useful extension that can be added to PHP with a little bit of effort:

• Open up your Terminal.app
• To explicitly build for 64 bit architecture export CFLAGS="-arch x86_64"
• Download libmcrypt from sourceforge http://sourceforge.net/projects/mcrypt
• Unpack the archive
• cd libmcrypt
• ./configure --disable-shared
• make
• sudo make install
• download PHP 5.2.6 source from http://www.php.net/get/php-5.2.6.tar.bz2/from/a/mirror
• unpack the archive and go into the php-5.2.6/ext/mcrypt/ dir
• phpize
• ./configure
• make
• sudo make install
• verify the extension is 64 bit: file /usr/lib/php/extensions/no-debug-non-zts-20060613/mcrypt.so

/usr/lib/php/extensions/no-debug-non-zts-20060613/mcrypt.so: Mach-O 64-bit bundle x86_64

To actually use the extension, you can simply create a symbolic link to it. For example:

• cd ~/Sites
• ln -s /usr/lib/php/extensions/no-debug-non-zts-20060613/mcrypt.so

Example code: mcrypt.php

Drop the following code into your ~/Sites directory to verify everything is working:

    <?php

    if ( ! extension_loaded('mcrypt') ) {
        dl('mcrypt.so');
    }

    $key   = "this is a secret key";
    $input = "Let us meet at 9 o'clock at the secret place.";

    $td = mcrypt_module_open('tripledes', '', 'ecb', '');
    $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
    mcrypt_generic_init($td, $key, $iv);
    $encrypted_data = mcrypt_generic($td, $input);
    mcrypt_generic_deinit($td);
    mcrypt_module_close($td);

    print_r($encrypted_data);

    ?>

Warnings and notices are PHP’s way of letting you know that you are utilising features in a non-standard way. If your code is omitting errors, then it should be fixed as soon as possible. Strict warnings are a class of errors that are turned off by default in most PHP installations. Turning on strict warnings gives you another level of error reporting, which is helpful to prevent you from using misusing functions, making sure your code is compatible with future PHP versions.

In the example here, using date() without explicitly setting a timezone will result in an E_STRICT warning. In this case, we are using a function called strictErrors to tell PHP to report all error types.

Example

    <?php

    function strictErrors() {
        $reporting_level = E_ALL;

        // if version of PHP < 6, explicity report E_STRICT
        if ( version_compare( PHP_VERSION, '6.0.0', '<' ) ) {
            $reporting_level = E_ALL | E_STRICT;
        }

        return error_reporting( $reporting_level );
    }

    // turn on strict error and warnings
    strictErrors();

    // produces strict warning
    echo date( "d-M-Y" );

    // no warning
    date_default_timezone_set( 'Europe/London' );
    echo date( "d-M-Y" );

    ?>

Further information

• PHP: error_reporting

This is the first in what I hope will be a regular series of posts on PHP best practices, inspired in part by Damian Conway’s Perl Best Practices book.

Historically, PHP has had two incompatible regular expression engines available, POSIX Extended and PCRE (Perl Compatible Regular Expressions). Arguably, Perl-compatible regular expressions are more powerful since they support non-greedy matching, assertions, conditional subpatterns and a number of other features not supported by POSIX Extended. More importantly, the POSIX Extended extension is deprecated as of PHP 5.3, meaning that a call to any of its functions, such as `ereg`, will emit a `E_DEPRECATED` notice. Therefore, for any regular expression functionality in your scripts, use the PCRE set of functions which are prefixed with `preg_`.

Example

    $pattern = '/Hello/x';
    $subject = 'Wake up and say Hello.';
    $matches = array();

    if ( preg_match( $pattern, $subject, $matches ) ) {
        print_r( $matches );
    }

Output:

    Array ( [0] => Hello )

Further information

• PHP: PCRE – Manual

This is a quick and dirty guide to the absolute minimum you need to get up and running with PhpDocumentor.

One of the slightly off-putting aspects of PhpDocumentor is the amount of tags (`@`) that are available, which can initially be overwhelming. e.g. see PEAR example:

PEAR sample file

This guide shows you the most important tags that you need to have in your documentation by means of an actual example: `Accumulator.php`.

Assumptions

• You are on a UNIX based machine, which includes Linux and Mac OS X.
• You are documenting object oriented rather than procedural code

Install

PhpDocumentor is part of PEAR. Install is easy:

    sudo pear install phpdocumentor

Documenting your source code

The rules:

• One class per file
• One docbook block for the class, not for the file
• Filename is `.php`

For the class:

• short description
• code example
• `@author`

For each attribute:

• short description
• `@var`

For each method:

• short description
• `@param`
• `@return`
• `@see`

Example class with documentation

Accumulator.php

    <?php

    /**
     * An instance of this class represents a counting machine
     *
     * 
     * require_once 'Accumulator.php';
     *
     * $acc = new Accumulator( 10 );
     *
     * $acc->addNum( 20 );
     *
     * echo $acc->getTotal();
     * 
     *
     * @author Glen Scott 
     */
    class Accumulator {
        /**
         * The running total
         *
         * @var int
         */
        private $_number;

        /**
         * Create an instance, optionally setting a starting point
         *
         * @param int $initial an integer that represents the number
         *                     to start counting from
         * @access public
         */
        public function __construct( $initial = 0 ) {
            $this->_number = $initial;
        }

        /**
         * Adds a number to the running total
         *
         * @param int an integer to add to the running total
         */
        public function addNum( $num ) {
            $this->_number += $num;
        }

        /**
         * Returns the current total
         *
         * @return int returns the current running total
         * @see Accumulator::$number
         */
        public function getTotal() {
            return $this->_number;
        }
    }

Creating your documentation

phpdoc –filename Accumulator.php –target docs

The `”docs”` directory is created and some HTML files are generated. Load `docs/index.html` into your browser to read your documentation.

Possible issues

`”phpdoc: command not found”`. This means that the documentation generator script is not in your path. Run `”pear config-get bin_dir”` and add this directory to your shell’s `$PATH` environment variable.

Links

• PhpDocumentor

What’s new in PHP V5.3, Part 2: Closures and lambda functions


Cannot modify header information - headers already sent by (output started at myinclude.php:16) in myscript.php on line 15


Zend Framework: Documentation

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