Mirmo Dynamics

While setting up a test server for some software I wrote at the office, I eventually noticed the following notice:

Notice: Use of undefined constant self - assumed 'self'

That surprised me, because 1) I though self were some kind of "superglobal" constant or a special token of the parser, always automatically available in a static method and 2) the code works. So what's up in there ? Let's make a simple test:

<?php

class foo {
	static public function bar() {
		var_dump(is_callable(array('self', 'foobar')));
		var_dump(is_callable(array(self, 'foobar')));

		var_dump(class_exists('self'));
		var_dump(class_exists(self));

		self::foobar();
	}

	static public function foobar() {
	}
}

foo::bar();

Executing the above code will yeld the following result:

bool(true)

Notice: Use of undefined constant self - assumed 'self' in /home/geoffreyb/test.php on line 6
bool(true)
bool(false)

Notice: Use of undefined constant self - assumed 'self' in /home/geoffreyb/test.php on line 9
bool(false)

What do we learn here ? Not much actually. It seems like self as a constant is only available when used with the scope resolution operator, aka double-colon or paamayim nekudotayim. When you want to use it in, for example, a callback definition, use a string representation of self:

<?php

is_callable(array('self', 'bar'));
call_user_func(array('self', 'bar'));

Which, while making absolutely no sense at all, works. Another way to get around this is to use the get_class() function that, without any argument, will return the name of the class you're currently in (foo in my example).

After a bit more investiging, I found out that there is nothing special about the self token, which is actually a string token. You can check this very easily with the following code:

<?php

class foo {
	static public function bar() {
		self::foobar();
	}
}

var_dump(token_get_all(file_get_contents(__FILE__)));

Somewhere inside the output, you'll find the following piece of text:

  array(2) {
    [0]=>
    int(307)
    [1]=>
    string(4) "self"
  }

And the token id 307 is resolved by token_name to string.

Today I ran into an issue that I already ran into a few weeks ago when I did not have time to dig up, but today I had this time (this plus it's a really annoying issue as you'll see). The main symptom is that PDO does not throws exceptions when you'd expect it to. It's very annoying. The reason, in my case, seems to be that I am querying an old mysql (3.23.x in my case but any 4.x will do according to this bug report). I was not able to find any info from google, so I'm posting this here so that people know :-)

A PEAR package for the 1.0.2 version of the Zend Framework is now available from the PEAR PHPMafia channel. As usual, to install just issue the following:

UPDATE: new version (r105) available.

The component was given a little rewrite as expected, but maybe a little bit later than I would have wanted to :-) So it now has its own Rowclass proxy from which you can pull various infos such as current page, page range, next page, etc all exposed as getter methods (that is, getCurrentPage, getPageRange, getNextPage, etc), which you won't really have to worry about since the brand new view helper will take care of that for you. Usage has changed a little, bit, so let's first have a look at what's happening from the controller point of view:

Not much changed here, except we don't need anymore to call getPaginationInfos(). Nice ! Now the big part, the view:

The view helper uses the neat composite helper trick from naneau - which is a really cool trick, great job naneau my fellow no-more-a-bunny. The first call inits the helper, feeding him the necessary rowset to work on, then you just have to call the methods you need to draw the navigation links. As you may expect, previous and next method will return nothing if no page is available (actually, they return their second argument, which defaults to an empty string).

Also, it's worth noting that the bundled Riskle_Db_Table features the patch from Erik, as well as a totally rewritten fetchCols method (now uses a straight Zend_Db_Select object instead of the ugly trick it used to use).

My code is no longer available on subversion, I moved the project to assembla. Instead ou can download this component from the riskle space's files board (direct download), the file contains all classes needed for the component to work, just unzip it in your include_path and you're set.

As usual, any comments are more than welcome.

If you're wondering how much of a hassle it would be to migrate your app / codebase to php5, try the following command line (after having installed the php5-cli package of course):

find . -name "*.php" -exec /usr/bin/php5 -l {} \; | grep -v 'No syntax errors'

It'll show you all the files with syntax errors in it.

Sometimes you have to pass an object data to another object, or to another layer of your application (who said controller/view ?), while ensuring that the receiving entity will not be able to run business code encapsulated in your class. In the Zend Framework, several objects provide a toArray method, but that is not always sufficient as sometimes you'd like to keep with the $object->varname syntax.

That is where the Transfer Object arrives. While the preceding definition is not exact (that's not the real purpose of the Transfert Object in the J2EE spirit), This is the most common use that PHP Developers can make of it nowadays I think. So I came up with a very light implementation of a concept which I hope can prove useful for any folks getting by there.

See also:

• Martin Fowler's Value Object and Data Transfer Object
• The Transfert Object as a Core J2EE Pattern

While the Zend Framework's manual is somewhat quite good, it lacks a feature that make it a really good manual: search. I find it very frustrating to not be able to make a simple search and therefor having to browse through the extensive TOC to find what I'm actually looking for. Here enters the very handy Google co-op service which allows creation of custom search engines based on Google's indexes. It do not takes more than five minutes to setup a simple search engine, thus providing search capability to the manual :-)

And as a good news never comes alone, I also made the OpenSearch plugin for it.

UPDATE

I made a simpler url to remind of: http://zend.riskle.com/search/ and updated the opensearch thing to use that url.

This is a simple controller plugin for the Zend Framework which enable RESTful behaviour. It basically adds the HTTP method name to the action name, so that the URL http://example.com/foo/bar will be dispatched to FooController::barGetAction on a GET, FooController::barPostAction on a POST, etc.

Allez hop, la RC3 du Zend Framework est sortie (il y a 2 jours).

J'en profite pour faire un peu de pub pour zftalk, un chan IRC sympa.

Dernière ligne droite avant les premières 1.0 RC, la beta 0.9.3 du Zend Framework est sortie, et son package est disponible sur le channel PEAR PHPMafia.