Separating Logic/Style in PHP properly

Question

I\'m just wondering what is the best way to separate logic components from the layout in a PHP web project?

The content is stored in MySQL, the logic is PHP and the

Answer 1

Just use some template engine.
The most familiar one is PHP itself.

here is the very basic example of CRUD application:
the logic part doing only data manipulation

<?  
mysql_connect(); 
mysql_select_db("new"); 
$table = "test"; 
if($_SERVER['REQUEST_METHOD']=='POST') { //form handler part: 
  $name = mysql_real_escape_string($_POST['name']); 
  if ($id = intval($_POST['id'])) { 
    $query="UPDATE $table SET name='$name' WHERE id=$id"; 
  } else { 
    $query="INSERT INTO $table SET name='$name'"; 
  } 
  mysql_query($query) or trigger_error(mysql_error()." in ".$query); 
  header("Location: http://".$_SERVER['HTTP_HOST'].$_SERVER['PHP_SELF']);  
  exit;  
}  
if (!isset($_GET['id'])) { //listing part: 
  $LIST=array(); 
  $query="SELECT * FROM $table";  
  $res=mysql_query($query); 
  while($row=mysql_fetch_assoc($res)) $LIST[]=$row; 
  include 'list.php'; 
} else { // form displaying part: 
  if ($id=intval($_GET['id'])) { 
    $query="SELECT * FROM $table WHERE id=$id";  
    $res=mysql_query($query); 
    $row=mysql_fetch_assoc($res); 
    foreach ($row as $k => $v) $row[$k]=htmlspecialchars($v); 
  } else { 
    $row['name']=''; 
    $row['id']=0; 
  } 
  include 'form.php'; 
}  
?>

and two simple templates responsible for output,
form.php

<? include TPL_TOP ?>
<form method="POST">
<input type="text" name="name" value="<?=$row['name']?>"><br>
<input type="hidden" name="id" value="<?=$row['id']?>">
<input type="submit"><br>
<a href="?">Return to the list</a>
</form>
<? include TPL_BOTTOM ?>

and list.php

<? include TPL_TOP ?>
<a href="?id=0">Add item</a>
<? foreach ($LIST as $row): ?>
<li><a href="?id=<?=$row['id']?>"><?=$row['name']?></a>
<? endforeach ?>
<? include TPL_BOTTOM ?>

Though there are plenty of other template engines, of different kinds and ideologies.

Answer 2

Try an MVC framework like

CodeIgniter: http://codeigniter.com/

or CakePHP: http://cakephp.org/

(Cake has got a steeper learning curve, but does a lot more stuff automagically)

Here's what MVC is about: http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller

Answer 3

Use a Template Engine, e.g. Smarty.

Alternatively just use HTML with embedded php for templates, just be careful not to put too much logic into the template.