PHP – Creating a Custom PHP Template Engine

PHPtemplates

I've been developing a custom PHP template engine to suit just my needs and also to get a little more practice with PHP.

What I did was to create a Template class that simply receives as constructor parameter a path to a template file and a string that should be the placeholder for the contents of the pages. In that case, the template file is an HTML file with some placeholders written as [placeholder]. These will be filled with real content by another class. So for instance, [title] should be filled with the title, [content] with the content of the selected page and so on.

I've created also a Page class that receives as constructor parameter the directory of the pages and then has methods to set which name of file it should use (this is filled in as we like in the initialization, when working with friendly URL's the most common way I use this is setting as the first piece of the URL) and methods to set more data as pairs of placeholder string and real content.

My only problem is with how to deal with titles and meta tags. For each page there's a title and a collection of meta tags. My only way to deal with this was to create in different files one array with titles and one array with meta tags. Both of them receives as index the name of the page file. So for instance $titles["home"] should be the title of the home page and $meta_tags["home"] should be the html code for the meta tags of the home page.

The problem is that as soon as there are lots of pages this will have one unecessary cost of memory: the system would be loading for every requests all the titles and all meta tags, while it must load only the required one. I thought on using database, but it seems like killing one ant with an atomic bomb. So the next best thing I thought of was XML.

Now, what's the best solution for this kind of situation? Use XML, use a MySQL database, or some other method?

As I've said, I know that the recommended is that we use the template engines that are already out there since they are tested lots of times, are already stable and so on, but I'm struggling with those things as a way to get more practice developing with PHP.

Thanks very much in advance for the help. Also, I didn't think it was needed to post any code I've written, but if some of the code will help, please ask and I'll post it.

Best Answer

I'm not sure if I've understood your problem correctly or not, but that seems to me that Loading the data is your problem, not anything else related to your template engine, right?

If yes, my questions is, where are the other contents of your application? I mean where is the page content? Put the meta tags, titles, etc. just where you have the other data.

If you're storing your page content in the database, then add these meta tags (whatever) to your database, load them when you loading the page content and then just pass them to your template engine.

If you have static pages, then add something like these to each page, and later you can grab it and pass it to your template engine:

<?php
/* Sample.php */
$title = 'Sample Page';
$meta = 'whatever';
?>
<!-- Page Content -->
<h3>Welcome!</h3>
...

P.S. BTW, such an array of titles and meta tags is not an issue for a real-world web server.

Related Solutions

Database Design – Storing Hierarchical Templates in a Database

for your reference you can see Active directory implementation it is pretty much the same thing. but i would prefer you must use hierarchical database for this purpose.

you problem has solution is in No-SQL database. there are many databases with key value store schema under no-SQL umbrella. Relational databases are not design for this purpose although you can use them by having parent child relationships, insertion is fine but we will face difficulties while retrieving data.

if there is no restriction on changing the database you must go with that. but if you have no option other than SQL DB as you might have been using SQL for relational purposes it would be cumbersome to have separate DB base for this purpose only.

but again don't use SQL DB for this purpose.

Php – How to structure template system using plain PHP

I wouldn't do the second approach as the parameters aren't named.

A well-written essay on describing how a template system should work is coming from Parr, it's often quoted by people writing template systems and/or web-mvc frameworks.

Personally, what I usually prefer is to implement an ArrayObject class with a properties array, and the template would refer to $this->propertyName, which in fact would be the template object's $this->property['name']. This could be also achieved simply by using __set and __get, so:

class Template {
  private $_scriptPath=TEMPLATE_PATH;//comes from config.php
  public $properties;
  public function setScriptPath($scriptPath){
    $this->_scriptPath=$scriptPath;
  }
  public function __construct(){
      $this->properties = array();
  }
  public function render($filename){

   ob_start();
   if(file_exists($this->_scriptPath.$filename)){
     include($this->_scriptPath.$filename);
    } else throw new TemplateNotFoundException();
    return ob_get_clean();
  }
  public function __set($k, $v){
      $this->properties[$k] = $v;
  }
  public function __get($k){
      return $this->properties[$k];
  }
}

and a template would look like:

<html>
      <head>
         <title><?=$this->title?></title>
      </head>
      <body>Hey <?=$this->name?></body>
</html>

and invoking it would look like:

$view = new Template();
$view->title="Hello World app";
$view->properties['name'] = "Jude";
echo $view->render('hello.inc');

As far as I remember, this is how the old Symfony 1.x and the Zend_View template engines look like, and for me it's fine.

Best Answer

Related Solutions

Database Design – Storing Hierarchical Templates in a Database

Php – How to structure template system using plain PHP

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