So what's wrong with this site anyway?

OK, so this site goes 'bang' occasionally. Not ideal for a site that purports to advise on coding and project management techniques, so what's wrong?



Well, part of the issue is that I wouldn't recommend that anyone else code a site in the way that this one's actually being maintained. This code's the nearest I have to a playground, and so sometimes it falls off the swings. A lot of the code's unit tested (and those tests work), but there's still some weird race conditions and sporadic failures.



Why?



Because there are bits of this codebase that date back about 4 years. When I started, PHP4 was young (and I was, well, younger) and I knew nothing of object code, so the first 'PhaseCode' release was purely procedural. No, you can't see that codebase, but if you drop back into the archives you can have a good laugh at my youthful naivety in some of the design notes. These days you can still laugh, but I'm losing that particular excuse.



Then at some point (I can't work it out from the archive offhand) I started wrapping the code up in classes. These classes got slung together in bunches of files that were loosely grouped by "module", and ended up as something of a require() maze.



So, I decided to put away such childish foolishness (I have a feeling this was about the start of last year) and move to a class structure I could __autoload()! Wow!



Except that I did it not in the Zend format of Some/Class/Here.php, but in an older pattern of phasetwo_className_Class.php in a flat structure, which was fairly common around then - I think Smarty still uses it. This was a step forward, but it was a rather different forward from the one I'm now heading in.



Now, I'm using Zend's Some/Class/Here.php (since about this time last year, I think), which is based on a fairly shameful kludge (or, depending on viewpoint, a quick and pragmatic solution to manage a codebase for which no-one else is paying, and of which no-one else has to suffer the pain of maintenance - my pro codebases are stunning ;). That hack is as follows:



  • Classes starting with phasetwo_ are autoload()ed from lib/phasetwo_someClass_Name_Class.php

  • Classes starting with PhaseTwo_ are autoload()ed from lib/PhaseTwo/SomeClass/Name.php



Yeah, I can hear you wincing from here. Now you know my shame; my autoloader switches by case. The real fun comes as I move files from one location to the other; as I do so I have to change the case of every mention of that class in the rest of the code; sometimes bits escape, but the code works if the correct case was mentioned first, because while my autoloader is case sensitive, PHP's class naming isn't. (Yes, I heard that wince too). This provides no end of fun opportunities for hard-to-find bugs and race conditions, some of which make no sense even after I fix them. Failures inside callbacks (including the ancient template parser I still use) are even harder to find as the PHP interpreter tends to fail without either error or exception.



But hey, it's all fun ;) And now you know why I keep blowing my site up - because I'm not allowed to do it to anyone else's.



(But, seriously folks - don't try this at home ;)

Posted by parsingphase, 2008-07-17 22:59

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