使用PHP变量进行网站导航

Question

I've used this method on a few website builds with no obvious problems. But I'm wondering if it's an okay/proper way to utilize PHP variables as website navigation/page indicators so that site-wide changes can be easily managed in 1 file (upper.php)? Are there any drawbacks? Maybe too many requests to the server, load times, improper coding or negative S.E.O. ramifications?

I've omitted surrounding code such as < body >, etc. for simplicity and indicated where more code would be with "..."

index.php

<?php $urhere="home"; include ("upper.php"); ?>
    <div>This is the Home page content</div>   
... 

about.php

<?php $urhere="about"; include ("upper.php"); ?>
    <div>This is the About page content</div>
...    

contact.php

<?php $urhere="contact"; include ("upper.php"); ?>
    <div>This is the Contact page content</div> 
...

upper.php

...

<meta name="description" content="
    <?php
        if ($urhere=="home") echo "Home page description";
        if ($urhere=="about") echo "About page description";
        if ($urhere=="contact") echo "Contact page description";
    ?>

...

<title>
    <?php
        if ($urhere=="home") echo "Home page Title";
        if ($urhere=="about") echo "About page Title";
        if ($urhere=="contact") echo "Contact page Title"; 
    ?>
</title>

...

<div id="nav">
    <ul>
      <li><a href="/home"<?php if ($urhere=="home") echo " class=\"urhere\""; ?>>Home</a></li>
      <li><a href="/about"<?php if ($urhere=="about") echo " class=\"urhere\""; ?>>About</a></li>
      <li><a href="/contact"<?php if ($urhere=="contact") echo " class=\"urhere\""; ?>>Contact</a></li>
    </ul>
</div>

Answer 1

I see some serious maintenance problems with this approach.

Every time you add a new page, you have to add three (for now) if-statements.

upper.php knows too much about other pages -- their window titles and metadata.

I would suggest that instead of using the $urhere variable to make all the decisions in upper.php, you set variables, like window title and metadata, which can be directly used by upper.php. Here's an example:

upper.php

<meta name="description" content="<?php echo $description ?>"/>
...
<title><?php echo $title ?></title>
...
<?php
$pageTypeToLinkMap = array(
    'home' => array(
        'url' => '/home',
        'linkText' => 'Home'
    ),
    'about' => array(
        'url' => '/about',
        'linkText' => 'About',
        'sublinks' => array(
            'who-we-are' => array(
                'url' => '/who-we-are',
                'linkText' => 'Who We Are'
            ),
            'what-we-do' => array(
                'url' => '/what-we-do',
                'linkText' => 'What We Do',
                'sublinks' => array(
                    'business' => array(
                        'url' => '/business',
                        'linkText' => 'Business'
                    ),
                    'technology' => array(
                        'url' => '/technology',
                        'linkText' => 'Technology'
                    )
                )
            )
        )
    ),
    'contact' => array(
        'url' => '/contact',
        'linkText' => 'Contact'
    )
);

function getLinkElement($pageType, array $linkData)
{
    $class = $urhere == $pageType ? 'urhere' : '';
    $anchorElement = "<a href=\"$linkData[url]\" class=\"$class\">$linkData[linkText]</a>";

    if (isset($linkData['sublinks']))
    {
        $sublinkElements = array();

        foreach ($linkData['sublinks'] as $sublinkPageType => $sublinkData)
            $sublinkElements[] = getLinkElement($sublinkPageType, $sublinkData);

        $sublinksListElement = '<ul>' . implode($sublinkElements) . '</ul>';
    }
    else
        $sublinksListElement = '';

    return "<li>$anchorElement$sublinksListElement</li>";
}
?>
<div id="nav">
    <ul>
        <?php foreach ($pageTypeToLinkMap as $pageType => $link) echo getLinkElement($pageType, array $link); ?>
    </ul>
</div>

index.php

<?php
$pageTitle = "Home";
$description = "This is home.";
$urhere = "home"; // I guess you still need this variable to make decisions in the "nav" div.
?>
<div>This is the Home page content</div>

about.php

<?php
$pageTitle = "About";
$description = "About us";
$urhere = "about";
?>
<div>This is the About page content</div>

---

EDIT

In response to your comment, here's how you can improve your upper.php while keeping the same original structure:

upper.php

<?php
$titles = array(
    'home' => 'Home page Title',
    'about' => 'About page Title',
    'contact' => 'Contact page Title'
);

$descriptions = array(
    'home' => 'Home page description',
    'about' => 'About page description',
    'contact' => 'Contact page description'
);

$linkClasses = array_fill_keys(array_keys($titles), '');
$linkClasses[$urhere] = 'urhere';
?>

...

<meta name="description" content="<?php echo $descriptions[$urhere] ?>"/>

...

<title><?php echo $titles[$urhere] ?></title>

...

<div id="nav">
    <ul>
        <li><a href="/home" class="<?php echo $linkClasses['home'] ?>">Home</a></li>
        <li><a href="/about" class="<?php echo $linkClasses['about'] ?>">About</a></li>
        <li><a href="/contact" class="<?php echo $linkClasses['contact'] ?>">Contact</a></li>
    </ul>
</div>

There you go, if-less code.