Mac/iPhone

Focussing on important apps

• Backdrop is a tool I’ve mentioned before. The aim is simple; it blacks out your screen allowing you to pick only the essential applications to focus on.
• WriteRoom is a decent text editor that uses the same black-out effect as Backdrop, allowing you to concentrate purely on writing.

Removing notifications

• Growl notifications seemed like a good idea once-upon-a-time. More often than not, they serve only as an annoyance and break my concentration.
• I’ve disabled iPhone push notifications for Mail as e-mail is never important enough that I need to read it straight away

Online

The key question that I kept coming back to as I sifted through this mess is

How does this support my life as it is now?

Unsubscribing from e-mail alerts

I’ve unsubscribed from the following e-mail alerts:

• Facebook notifications (57 different notification types in all!)
• Twitter user follows
• Google alerts
• Dozens of music and tech mailing lists

Knowing that my level of e-mail will now drop, I’m less inclined to check it as often.

Unsubscribing from blog RSS feeds

I had 82 feeds in my feed reader, and I realised that I read new items from them very rarely. I’ve now unsubscribed from all but 3;

• Miško Hevery
• myfootballwriter.com/norwichcity
• Code: Flickr Developer Blog

I’m sure these actions will be helpful in the long run, I am hoping this is a step towards a less overwhelming environment.

I was disappointed to find that the OU offers a dissertation template in Microsoft Word format only, so I’ve knocked together a LaTeX version which I’m hoping will be of use to others.

• source file: http://github.com/glenscott/ou/blob/master/template.tex
• PDF output: m801-template.pdf

At the moment it’s quite rough, but it should provide a good starting point for further development.

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.

Can I sync with my iPhone over the air?

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

    use MooseX::Declare;

    class BankAccount {
        has 'balance' => ( isa => 'Num', is => 'rw', default => 0 );

        method deposit (Num $amount) {
            $self->balance( $self->balance + $amount );
        }

        method withdraw (Num $amount) {
            my $current_balance = $self->balance();
            ( $current_balance >= $amount )
                || confess "Account overdrawn";
            $self->balance( $current_balance - $amount );
        }
    }

    class CheckingAccount extends BankAccount {
        has 'overdraft_account' => ( isa => 'BankAccount', is => 'rw' );

        before withdraw (Num $amount) {
            my $overdraft_amount = $amount - $self->balance();
            if ( $self->overdraft_account && $overdraft_amount > 0 ) {
                $self->overdraft_account->withdraw($overdraft_amount);
                $self->deposit($overdraft_amount);
            }
        }
    }

Firstly, yes, that is indeed Perl. Secondly, wow: it actually _looks_ like a class definition. And this was the big win for me, as anyone coming from a Java or PHP background will find it trivial to understand what’s going on here. The main point is that by using MooseX::Declare, you are moving towards a more declarative programming style describing _what_ the program should do rather than _how_ it should achieve it. So, no more unrolling `@_`

Links

• MooseX::Declare on CPAN
• Piers Cawley’s blog – Just A Summary

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