{"id":45,"date":"2008-03-12T08:02:47","date_gmt":"2008-03-12T07:02:47","guid":{"rendered":"https:\/\/paul-anton.vanhandel.at\/?p=45"},"modified":"2008-03-12T08:02:47","modified_gmt":"2008-03-12T07:02:47","slug":"php-class-constants-a-diatribe","status":"publish","type":"post","link":"https:\/\/paul-anton.vanhandel.at\/?p=45","title":{"rendered":"PHP class constants – a diatribe (sort of)"},"content":{"rendered":"

So constants are constant, no kidding, eh?<\/strong><\/em>
\n
\nBut why to hell can’t I assign variable content to it? Wouldn’t make sense, you say? Constants ARE constant?<\/p>\n

ASSIGN – NOT REassign, buddy!<\/p>\n

You won’t find a solution in this text. There are workarounds all over the net – that’s not the issue here – I simply had the urge to nag, complain an moan about that fact .<\/p>\n

Figure this (just making up this example for demonstration, but it’s as good as any):
\nYou have a class SpitOutFQUserImageURL<\/strong> to get you your users profile picture’s fully qualified URL.
\n(yeah, you read right – FQ is not a new abbreviation for Fucking :))<\/p>\n

Right on – you’ve got your basic config file with all the well defined constants – you want to be as hardware and software agnostic as you can be.<\/p>\n

First you have the protocol defined in PROTOCOL<\/strong>: http:\/\/<\/em>
\nYou got the constant SITEBASE<\/strong> : Let it be fileyourthoughts.com<\/em>.
\nYou got the subdomain defined in SUBDOMAIN<\/strong>: www<\/em>
\nThen there is MEDIAPATH<\/strong>: mediastore<\/em>
\nFinally there’s IMAGEPATH<\/strong> being: userimages<\/em><\/p>\n

Now that class is simple enough, does what it has to do bla bla bla and then a method builds the FQ URL:
\npublic function spitItOut() {
\n$urlBase = PROTOCOL . SUBDOMAIN . '.' . SITEBASE . '\/' . MEDIAPATH . '\/' . IMAGEPATH . '\/' . $this->getYourFuckingImage($userId);
\nreturn $urlBase;
\n}
\n<\/code><\/p>\n

Yeah yeah, we could just leave it like that and it will work.<\/p>\n

But I don’t like it! Why can’t I – for readability if not anything else – define a class constant USERIMAGEPATH like that:
\n
\nclass SpitOutFQUserImageURL {
\nconst USERIMAGEPATH = PROTOCOL . SUBDOMAIN . '.' . SITEBASE . '\/' . MEDIAPATH . '\/' . IMAGEPATH . '\/';
\n}
\n<\/code><\/p>\n

and have my method read like:
\n
\npublic function spitItOut() {
\n$userImg = self::USERIMAGEPATH . $this->getYourFuckingImage($userId);
\nreturn $userImg;
\n}<\/code><\/p>\n

Halt! Don’t copy that stuff above – it won’t work!
\nI wish it would!<\/p>\n

Why?<\/p>\n

If you’re working on larger projects you work with packages, that, if done right, can be re-used in other projects (or part of the same project) w\/o doing to much adjustments.
\nNow imagine this class here is part of a package that does all the image handling you need and you want to use it somewhere else – different project, different environment, DIFFERENT<\/strong> configuration.<\/p>\n