Les Marqueurs Conditionnels peuvent être utilisés dans vos Thèmes pour décider du contenu à afficher sur une page spécifique ou comment ce contenu doit être affiché en fonction de conditions que remplit cette page. Par exemple, si vous voulez insérer un texte particulier au-dessus d'une série d'Articles, mais seulement sur la page principale de votre blog, avec le Marqueur Conditionnel is_home(), cela devient facile.
Ces Marqueurs sont en relation étroite avec la Hiérarchie des Modèles de WordPress.
Tous les Marqueurs Conditionnels testent si une condition est remplie, et retourne ensuite TRUE ou FALSE. Les conditions selon lesquelles les différents Marqueurs renvoient TRUE sont listées ci-dessous. Les paramètres acceptés par certains marqueurs sont également mentionnés.
Concerne les Articles qui sont affichés unitairement (en général, utilise le fichier single.php des thèmes).
Cette section concerne les Pages WordPress, et pas n'importe quelle page générique de votre blog.
Malheureusement, il n'existe pas encore de fonction is_subpage() (pour tester si une page est une sous-page). On peut cependant, contourner ce problème :
See also is_archive() and Category Templates.
See also is_archive() and Author Templates.
See also is_archive().
Here are working samples to demonstrate how to use these Marqueurs Conditionnels.
This example shows how to use is_single() to display something specific only when viewing a single post page:
if (is_single())
{
echo 'This is just one of many fabulous entries in the ' . single_cat_title() . ' category!';
}
If someone browses our site by date, let's distinguish posts in different years by using different colors:
<?php
// this starts The Loop
if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
<h2 id="post-<?php the_ID(); ?>">
<a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title(); ?>">
<?php the_title(); ?></a></h2>
<small><?php the_time('F jS, Y') ?> <!-- by <?php the_author() ?> --></small>
<?php
// are we showing a date-based archive?
if (is_date())
{
if (date('Y') != get_the_date('Y'))
{
// this post was written in a previous year
// so let's style the content using the "oldentry" class
echo '<div class="oldentry">';
} else {
echo '<div class="entry">';
}
} else {
echo '<div class="entry">';
}
the_content('Read the rest of this entry »');
?>
</div>
This example will display different content in your sidebar based on what page the reader is currently viewing.
<!-- begin sidebar -->
<div id="sidebar">
<?php
// let's generate info appropriate to the page being displayed
if (is_home()) {
// we're on the home page, so let's show a list of all top-level categories
echo "<ul>";
wp_list_cats('optionall=0&sort_column=name&list=1&children=0');
echo "</ul>";
} elseif (is_category()) {
// we're looking at a single category view, so let's show _all_ the categories
echo "<ul>";
wp_list_cats('optionall=1&sort_column=name&list=1&children=1&hierarchical=1');
echo "</ul>";
} elseif (is_single()) {
// we're looking at a single page, so let's not show anything in the sidebar
} elseif (is_page()) {
// we're looking at a static page. Which one?
if (is_page('About')) {
// our about page.
echo "<p>This is my about page!</p>";
} elseif (is_page('Colophon')) {
echo "<p>This is my colophon page, running on WordPress " . bloginfo('version') . "</p>";
} else {
// catch-all for other pages
echo "<p>Vote for Pedro!</p>";
}
} else {
// catch-all for everything else (archives, searches, 404s, etc)
echo "<p>Pedro offers you his protection.</p>";
} // That's all, folks!
?>
<form id="searchform" method="get" action="<?php echo $_SERVER['PHP_SELF']; ?>">
<div>
<input type="text" name="s" id="s" size="15" />
<input type="submit" value="<?php _e('Search'); ?>" />
</div>
</form>
</div>
<!-- end sidebar -->
When a visitor gets a 404 error page, it can be intimidating, and unhelpful. Using Wordpress, you can take the edge off a 404 and make it helpful to users, and yourself, too, by emailing whenever the user clicks a link to a non-existant page. If you use this, don't forget o
<p>You
<?php
#some variables for the script to use
#if you have some reason to change these, do. but wordpress can handle it
$adminemail = get_bloginfo('admin_email'); #the administrator email address, according to wordpress
$website = get_bloginfo('url'); #gets your blog's url from wordpress
$websitename = get_bloginfo('name'); #sets the blog's name, according to wordpress
if (!isset($_SERVER['HTTP_REFERER'])) {
#politely blames the user for all the problems they caused
echo "tried going to "; #starts assembling an output paragraph
$casemessage = "All is not lost!";
} elseif (isset($_SERVER['HTTP_REFERER'])) {
#this will help the user find what they want, and email me of a bad link
echo "clicked a link to"; #now the message says You clicked a link to...
#setup a message to be sent to me
$failuremess = "A user tried to go to $website"
.$_SERVER['REQUEST_URI']." and received a 404 (page not found) error. ";
$failuremess .= "It wasn't their fault, so try fixing it.
They came from ".$_SERVER['HTTP_REFERER'];
mail($adminemail, "Bad Link To ".$_SERVER['REQUEST_URI'],
$failuremess, "From: $websitename <noreply@$website>"); #email you about problem
$casemessage = "An administrator has been emailed
about this problem, too.";#set a friendly message
}
echo " ".$website.$_SERVER['REQUEST_URI']; ?>
and it doesn't exist. <?php echo $casemessage; ?> You can click back
and try again or search for what you're looking for:
<?php include(TEMPLATEPATH . "/searchform.php"); ?>
</p>
The Dynamic Menu Highlighting article discusses how to use the conditional tags to enable highlighting of the current page in a menu.