Good CMS design, templates and other issues + performance
am 22.01.2008 11:59:30 von webcm123
I hope you can spend some time and help me to select proper
application design and programming issues. :) I'm making new version
of CMS. I've been mostly theorizing about it for a recent months.
** Main Goals **
The main goal of this CMS is **speed and performance**. It should work
fast on slower or overloaded servers. Other goals are: easy appearance
editing, low size, care about input data (e.g. if error occurs, form
is sent to client with his input)... This CMS uses PDO for
communication with database.
** Let's start. Front Controller? **
There are some front controllers and other files in the main
directory:
* index.php - handles most requests
* login.php - login and logout
* adm.php - administration panel
* request.php - handling AJAX
* kernel.php - the most important file - connecting to database,
setting user, lang, style... general functions.
* other - e.g. go.php (downloading files, redirecting to links)
Are front controllers better solutions than separate module files
(which handle requests), e.g. art.php, image.php...?
** Details of index.php **
There are several versions of index.php depending on application
design.
http://pastebin.com/m7795f4c0 - index.php
http://pastebin.com/m41367c82 - content.php
** Problem 1. Access to
tag. **<br />
In previous versions, all modules were included in <body> tag by the<br />
main template. Document Title was always constant (set in<br />
configuration). However, it's better to display currently displayed<br />
subpage's title in <title> - for users and for Google. :) So I was<br />
forced to change something. The first action was **setting it only for<br />
content modules** (see it in posted URL above).<br />
<br />
<br />
** How to allow all modules to change <title> and <head>? **<br />
It's more difficult. I will explain you, why. However, let's begin<br />
from some methods of byways:<br />
<br />
* Output Buffering - everything what modules and their templates<br />
(included by modules) display, is buffered and assigned into $content<br />
variable. No problem with setting <title> and <head>. However, output<br />
buffering and assigning data into variable uses more RAM and may be<br />
little slower.<br />
<br />
* Template abstraction - all modules are included before <html>.<br />
They tell CONTENT object or class, what should be displayed. CONTENT<br />
class would offer some functions like: add(), info()... The main<br />
template displays content: <?= $content ?> (if we use __toString) or:<br />
Content::display(). Examples:<br />
<br />
> Content::add('filename', $data);<br />
> Content::info('information', $links);<br />
<br />
* Modules abstraction - modules are covered into classes. Before<br />
<html> index.php gets <title>'s text from them. In <body> the main<br />
template calls Module::display() or prints: <?= $module ?> (if we use<br />
__toString). Unfortunately, we **must use or define some global<br />
variables**, e.g. $cfg, $lang, $db, maybe too: $user... Example:<br />
<br />
> class News<br />
> {<br />
> /* some variables? */<br />
> /* __construct(), __toString() */<br />
}<br />
<br />
* FILE constant or $template variable - without abstraction. If<br />
FILE not defined, use $_GET['mod'] as FILE. Example:<br />
<br />
> define('FILE', 'template_file.php');<br />
<br />
* Another way?<br />
<br />
Remember that $lang and $db are used in all modules, $cfg in most,<br />
$user in some of them. They are global. What do you think about above<br />
methods and why?<br />
<br />
<br />
** What do we need to display? **<br />
In some modules we have to display only one template. However, most of<br />
them may:<br />
<br />
* use more templates - I think I can use include() in one of these<br />
templates<br />
<br />
* display only information - examples: "user doesn't exist", "No<br />
votes in this poll", "No results". In the first case we can display<br />
404 page instead. Sometimes we would like to put some links under the<br />
information.<br />
<br />
* comments - this submodule makes everything in global scope. In<br />
case of abstraction, I must cover it into class or function.<br />
<br />
<br />
** Code repetitions **<br />
There are 5 content modules - articles, files, images, links and news.<br />
4 of them have "details" page. In every of these 4 modules we must:<br />
<br />
* download data about item from database<br />
* IF item exists: download data of item's category (common)<br />
* display hierarchy of categories (common - function in kernel.php,<br />
but not good solution)<br />
<br />
Is it a problem to repeat some fragments of code? In the beginning of<br />
creating new version (you can see it in posted fragment of index.php)<br />
index.php included common content.php file. However, adding new type<br />
of content requires more modifications or we must create something<br />
like "content" plugins.<br />
<br />
Okay, I'm finishing this contemplation for now. I hope you will give<br />
me some advices. How would you solve my problems? Let's talk about it.<br />
If you want more examples or code of above methods, tell me. Remember<br />
that speed, performance and low RAM usage is important. :)</p>
</article>
<article>
<h2>Re: Good CMS design, templates and other issues + performance</h2><span>am 22.01.2008 20:15:45 von webcm123</span>
<p>Update:<br />
<br />
Maybe it won't be difficult to change <title> if I include all modules<br />
before <html>. However, there will be some consequences because of<br />
current CMS design.<br />
<br />
Which consequences? Read "what do we need to display?" section. :) How<br />
about displaying informations? Is it needed to make any abstractions<br />
(classes) or use output buffering? How about need of repeating some<br />
code in similar modules?<br />
<br />
PS. I don't want to use Smarty, etc.</p>
</article>
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