Object orientated coding

VirtualOdin

I have been using PHP and MySQL for a while now. I re-use quite a lot of modules of code in a functions page and ‘include’ some common display lines from separate files and use CSS quite a lot

I have reached the stage where I feel I should be doing more to re-use code, to be more 'object-orientated' as the book I have puts it. But I have not found a simple description of how to start or where to go.

Questions like:

what best goes in CSS
what properly goes in a functions page
what is the speed penalty of a giant functions page vs lots of separate pages
the merits of config pages
should pages be many small interlinked or larger self-contained using ‘?xxx’
does one have to start with a schema or can it develop as you go

When I download scripts by others that look as though they are object-orientated, I find it nigh on impossible to work out what is going on where, there are so many files and cross-references and (so far as I know) no PHP mapping tool or standard that enables me to get to the nub of what I want to change to customise the code for my purposes.

I completely see the logic of a more structured approach. Advice and tips welcome please.

Tim

laserlight

what best goes in CSS

This doesnt really concern PHP, actually.

what properly goes in a functions page

Any code that is used, or likely to be used, multiple times.

what is the speed penalty of a giant functions page vs lots of separate pages

Ah, there has been a small discussion on this around here, though it actually was off topic from the original post :o

the merits of config pages

Again, this would be related to the use of functions.
Also, if the config files store sensitive information (e.g. database username/password), they can be kept outside the document root to avoid web access if PHP does fail.

should pages be many small interlinked or larger self-contained using ‘?xxx’

In my opinion, this is personal preference.
You can have "small interlinked" pages that are accessed via the querystring ("?xxx")

does one have to start with a schema or can it develop as you go

Again this is personal preference, though it usually it advisable to have some sort of plan in mind.
Especially if you expect your website to grow to a substantial size.

Codewarrior123

what best goes in CSS

CSS should be used for formatting your document. This is really a question of howe clean your HTML markup is, but it could affect your PHP performance, in that using CSS classes properly might reduce the formatting markup you have to generate and transmit.

what properly goes in a functions page

Functions pages act as repositories for 'general' functions that are used throughout many other pages. This also allows you to group related functions in a single file for easy debugging.

what is the speed penalty of a giant functions page vs lots of separate pages

That's a hard call; giant pages take longer for the Zend engine to parse, while shorter pages take less time to parse, but require more calls to the underlying operating system to fetch.

Essentially: If you're dealing with a LOT of code (thousands of lines) the, it might be a good idea to break it up into several files if you only need specific, well defined subsets for individual pages. If you have to include every single smaller file in every page, you're still processing the code AND waiting on the operating system (bad idea.)

the merits of config pages

As mentioned earlier, config pages play a security role. The other thing they do is allow you to put a lot of related settings in a single page, so that you don't have to sift through functions to change settings. If you plan to distribute your application, it might be a good idea to seperate your config, because it's a lot less daunting to edit one file than digging through many filled with functions.

should pages be many small interlinked or larger self-contained using ‘?xxx’

I'm trying to decide for myself on this one. The GET variable version allows easier access to the site, at least programatically.

does one have to start with a schema or can it develop as you go

If your code is ever going to be reviewed at a later date (by yourself or anyone else) PLEASE, PLEASE use a well documented design schema.

Plus thinking it through will often provide you with a better understanding of exactly how to accomplish certain tasks before you get there.

I've tried many times to just blow through from the bottom up, but trust me, the top down is much better.