20个有用的WordPress函数代码

More and more clients are using WordPress as their CMS. As a designer or developer, you should really get into WordPress coding. To get started, you can read my WordPress theme guide and hacks. Now, I would like to recommend a resourceful WordPress site to you called WpRecipes. This post contains over 20 recipes that I hand picked from WpRecipes. If you have any good WordPress code or hacks that you want to share, feel free to send them over and I will post it.

先粘过来，研究明白再翻译一下，哈！

Display Tags In A Dropdown Menu

In your theme folder, paste the following code to the functions.php file. If you don’t have a functions.php file, create one.

<?php
function dropdown_tag_cloud( $args = '' ) {
	$defaults = array(
		'smallest' => 8, 'largest' => 22, 'unit' => 'pt', 'number' => 45,
		'format' => 'flat', 'orderby' => 'name', 'order' => 'ASC',
		'exclude' => '', 'include' => ''
	);
	$args = wp_parse_args( $args, $defaults );

	$tags = get_tags( array_merge($args, array('orderby' => 'count', 'order' => 'DESC')) ); // Always query top tags

	if ( empty($tags) )
		return;

	$return = dropdown_generate_tag_cloud( $tags, $args ); // Here's where those top tags get sorted according to $args
	if ( is_wp_error( $return ) )
		return false;
	else
		echo apply_filters( 'dropdown_tag_cloud', $return, $args );
}

function dropdown_generate_tag_cloud( $tags, $args = '' ) {
	global $wp_rewrite;
	$defaults = array(
		'smallest' => 8, 'largest' => 22, 'unit' => 'pt', 'number' => 45,
		'format' => 'flat', 'orderby' => 'name', 'order' => 'ASC'
	);
	$args = wp_parse_args( $args, $defaults );
	extract($args);

	if ( !$tags )
		return;
	$counts = $tag_links = array();
	foreach ( (array) $tags as $tag ) {
		$counts[$tag->name] = $tag->count;
		$tag_links[$tag->name] = get_tag_link( $tag->term_id );
		if ( is_wp_error( $tag_links[$tag->name] ) )
			return $tag_links[$tag->name];
		$tag_ids[$tag->name] = $tag->term_id;
	}

	$min_count = min($counts);
	$spread = max($counts) - $min_count;
	if ( $spread <= 0 )
		$spread = 1;
	$font_spread = $largest - $smallest;
	if ( $font_spread <= 0 )
		$font_spread = 1;
	$font_step = $font_spread / $spread;

	// SQL cannot save you; this is a second (potentially different) sort on a subset of data.
	if ( 'name' == $orderby )
		uksort($counts, 'strnatcasecmp');
	else
		asort($counts);

	if ( 'DESC' == $order )
		$counts = array_reverse( $counts, true );

	$a = array();

	$rel = ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) ? ' rel="tag"' : '';

	foreach ( $counts as $tag => $count ) {
		$tag_id = $tag_ids[$tag];
		$tag_link = clean_url($tag_links[$tag]);
		$tag = str_replace(' ', '&nbsp;', wp_specialchars( $tag ));
		$a[] = "\t<option value='$tag_link'>$tag ($count)</option>";
	}

	switch ( $format ) :
	case 'array' :
		$return =& $a;
		break;
	case 'list' :
		$return = "<ul class='wp-tag-cloud'>\n\t<li>";
		$return .= join("</li>\n\t<li>", $a);
		$return .= "</li>\n</ul>\n";
		break;
	default :
		$return = join("\n", $a);
		break;
	endswitch;

	return apply_filters( 'dropdown_generate_tag_cloud', $return, $tags, $args );
}
?>

Now open the file where you want the list to be displayed and paste the following code:

<select name="tag-dropdown" onchange="document.location.href=this.options[this.selectedIndex].value;">
	<option value="#">Tags</option>
	<?php dropdown_tag_cloud('number=0&order=asc'); ?>
</select>

Via: WpRecipes Credits: WpHacks

Get Posts Published Between Two Particular Dates

Just before the loop starts, paste the following code. Change the dates on line 3 according to your needs.

<?php
  function filter_where($where = '') {
        $where .= " AND post_date >= '2009-05-01' AND post_date <= '2009-05-15'";
    return $where;
  }
add_filter('posts_where', 'filter_where');
query_posts($query_string);
?>

Via: WpRecipes Credits: Codex

Get Posts With A Specific Custom Field & Value

Add the query_posts() function just before the Loop. Change the meta_key and meta_value accordingly. The example shown below will get posts with custom field "review_type" with value "movie".

<?php query_posts('meta_key=review_type&meta_value=movie');  ?>
<?php if (have_posts()) : ?>
<?php while (have_posts()) : the_post(); ?>
...
...

Via: WpRecipes Credits: John Kolbert

Get Latest Sticky Posts

Paste the following code before the loop. This code will retrieve the 5 most recent sticky posts. To change the number of retrieved posts, just change the 5 by the desired value on line 4.

<?php
	$sticky = get_option('sticky_posts');
	rsort( $sticky );
	$sticky = array_slice( $sticky, 0, 5);
        query_posts( array( 'post__in' => $sticky, 'caller_get_posts' => 1 ) );
?>

Via: WpRecipes Credits: Justin Tadlock

Automatically Insert Content In Your Feeds

In your theme folder, functions.php file, paste the following code. This code will automatically insert the content after each post in your RSS feeds. Hence you can use this code to insert ads or promotional text.

function insertFootNote($content) {
        if(!is_feed() && !is_home()) {
                $content.= "<h4>Enjoyed this article?</h4>";
                $content.= "<p>Subscribe to our <a href='#'>RSS feed</a></p>";
        }
        return $content;
}
add_filter ('the_content', 'insertFootNote');

Via: WpRecipes Credits: Cédric Bousmane

Display The Most Commented Posts

Just paste the following code in your template file where you want to display the most commented posts (eg. sidebar.php). To change the number of displayed posts, simply change the 5 on line 3.

<h2>Popular Posts</h2>
<ul>
<?php $result = $wpdb->get_results("SELECT comment_count,ID,post_title FROM $wpdb->posts ORDER BY comment_count DESC LIMIT 0 , 5");
foreach ($result as $post) {
setup_postdata($post);
$postid = $post->ID;
$title = $post->post_title;
$commentcount = $post->comment_count;
if ($commentcount != 0) { ?>

<li><a href="<?php echo get_permalink($postid); ?>" title="<?php echo $title ?>">
<?php echo $title ?></a> {<?php echo $commentcount ?>}</li>
<?php } } ?>

</ul>

Via: WpRecipes Credits: ProBlogDesign

Display Most Commented Posts In 2008

<h2>Most commented posts from 2008</h2>
<ul>
<?php
$result = $wpdb->get_results("SELECT comment_count,ID,post_title, post_date FROM $wpdb->posts WHERE post_date BETWEEN '2008-01-01' AND '2008-12-31' ORDER BY comment_count DESC LIMIT 0 , 10");

foreach ($result as $topten) {
    $postid = $topten->ID;
    $title = $topten->post_title;
    $commentcount = $topten->comment_count;
    if ($commentcount != 0) {
    ?>
         <li><a href="<?php echo get_permalink($postid); ?>"><?php echo $title ?></a></li>

    <?php }
}
?>
</ul>

Via: WpRecipes

Display Related Posts Based On Post Tags

This code will display related posts based on the current post tag(s). It must be pasted within the loop.

<?php
//for use in the loop, list 5 post titles related to first tag on current post
$tags = wp_get_post_tags($post->ID);
if ($tags) {
  echo 'Related Posts';
  $first_tag = $tags[0]->term_id;
  $args=array(
    'tag__in' => array($first_tag),
    'post__not_in' => array($post->ID),
    'showposts'=>5,
    'caller_get_posts'=>1
   );
  $my_query = new WP_Query($args);
  if( $my_query->have_posts() ) {
    while ($my_query->have_posts()) : $my_query->the_post(); ?>

      <p><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></p>
      <?php
    endwhile;
  }
}
?>

Via: WpRecipes Credits: MichaelH

Display The Number Of Search Results

Open search.php, copy and paste the following code.

<h2 class="pagetitle">Search Results for <?php /* Search Count */ $allsearch = &new WP_Query("s=$s&showposts=-1"); $key = wp_specialchars($s, 1); $count = $allsearch->post_count; _e(''); _e('<span class="search-terms">'); echo $key; _e('</span>'); _e(' — '); echo $count . ' '; _e('articles'); wp_reset_query(); ?></h2>

Via: WpRecipes Credits: ProBlogDesign

Display The Comment Page Number In The <Title> Tag

Open the header.php file. Paste the following code in between the <title> tag.

<?php if ( $cpage < 2 ) {}
else { echo (' - comment page '); echo ($cpage);}
?>

Via: WpRecipes Credits: Malcolm Coles

Display The Future Posts

The following code will display 10 future posts.

	<p>Future events</p>
	<?php query_posts('showposts=10&post_status=future'); ?>
	<?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>

			<p><?php the_title(); ?> <?php the_time('j. F Y'); ?></p>

	<?php endwhile; else: ?><p>No future posts.</p><?php endif; ?>

Via: WpRecipes

Randomize Posts Order

To randomize posts order, just add the following code before the Loop.

query_posts('orderby=rand');
//the Loop here...

Via: WpRecipes

Display Word Count Of The Post

Open single.php and paste the following code where you want to display the word count.

<?php function count_words($str){
     $words = 0;
     $str = eregi_replace(" +", " ", $str);
     $array = explode(" ", $str);
     for($i=0;$i < count($array);$i++)
 	 {
         if (eregi("[0-9A-Za-zÀ-ÖØ-öø-ÿ]", $array[$i]))
             $words++;
     }
     return $words;
 }?>

 Word count: <?php echo count_words($post->post_content); ?>

Via: WpRecipes

Fetch RSS Feeds

To display RSS feeds, you can use the WordPress built-in RSS parser. To do so, include the rss.php file, and then use its wp_rss() function.

<?php include_once(ABSPATH.WPINC.'/rss.php');
wp_rss('http://feeds2.feedburner.com/WebDesignerWall', 5); ?>

Via: WpRecipes

Highlight Searched Text In Search Results

Open search.php file and find the the_title() function. Replace it with the following:

echo $title;

Now, just before the modified line, add this code:

<?php
	$title 	= get_the_title();
	$keys= explode(" ",$s);
	$title 	= preg_replace('/('.implode('|', $keys) .')/iu',
		'<strong class="search-excerpt">\0</strong>',
		$title);
?>

Then open the style.css file. Add the following line to it:

strong.search-excerpt { background: yellow; }

Via: WpRecipes Credits: Joost de Valk

Display A Greeting Message On A Specific Date (PHP)

The following code will dispaly a greeting message only on Christmas day.

<?php
if ((date('m') == 12) && (date('d') == 25)) { ?>
    <h2>Merry Christmas!</h2>
<?php } ?>

Via: WpRecipes

Automatically Create A TinyURL For Each Post

Open the functions.php file and paste the following code:

function getTinyUrl($url) {
    $tinyurl = file_get_contents("http://tinyurl.com/api-create.php?url=".$url);
    return $tinyurl;
}

In the single.php file, paste the following within the loop where you want to display the TinyURL:

<?php
$turl = getTinyUrl(get_permalink($post->ID));
echo 'Tiny Url for this post: <a href="'.$turl.'">'.$turl.'</a>'
?>

Via: WpRecipes

Exclude Categories From Search

Open the search.php file in your theme folder, paste the following code before the Loop. The code will exclude categories with ID 1, 2, 3 in the search results.

<?php if( is_search() )  :
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
query_posts("s=$s&paged=$paged&cat=-1,-2,-3");
endif; ?>

//the Loop here...

Via: WpRecipes

Exclude Categories From RSS

Open the functions.php file from your theme. If your theme doesn’t have a functions.php file, create one. Paste the following code in it:

<?php function myFilter($query) {
    if ($query->is_feed) {
        $query->set('cat','-5'); //Don't forget to change the category ID =^o^=
    }
return $query;
}

add_filter('pre_get_posts','myFilter');
?>

Via: WpRecipes Credits: Scott Jangro

Using Shortcodes

Open the functions.php file, paste the following code.

<?php function wprecipes() {
    return 'Have you checked out WpRecipes today?';
}

add_shortcode('wpr', 'wprecipes');
?>

You’re now able to use the wpr shortcode. To do so, paste the following line of code on the editor (in HTML mode) while writing a post:

[wpr]

This short code will output the “Have you checked out WpRecipes today?” message.

Via: WpRecipes Source: Codex

Display The Number Of Your Twitter Followers

Paste the code anywhere you want to display the Twitter follower count. Replace "YourUserID" with your Twitter account in last line.

<?php function string_getInsertedString($long_string,$short_string,$is_html=false){
  if($short_string>=strlen($long_string))return false;
  $insertion_length=strlen($long_string)-strlen($short_string);
  for($i=0;$i<strlen($short_string);++$i){
    if($long_string[$i]!=$short_string[$i])break;
  }
  $inserted_string=substr($long_string,$i,$insertion_length);
  if($is_html && $inserted_string[$insertion_length-1]=='<'){
    $inserted_string='<'.substr($inserted_string,0,$insertion_length-1);
  }
  return $inserted_string;
}

function DOMElement_getOuterHTML($document,$element){
  $html=$document->saveHTML();
  $element->parentNode->removeChild($element);
  $html2=$document->saveHTML();
  return string_getInsertedString($html,$html2,true);
}

function getFollowers($username){
  $x = file_get_contents("http://twitter.com/".$username);
  $doc = new DomDocument;
  @$doc->loadHTML($x);
  $ele = $doc->getElementById('follower_count');
  $innerHTML=preg_replace('/^<[^>]*>(.*)<[^>]*>$/',"\\1",DOMElement_getOuterHTML($doc,$ele));
  return $innerHTML;
}
?>

<?php echo getFollowers("YourUserID")." followers"; ?>

Via: WpRecipes

Display FeedBurner Subscriber Count In Text

<?php
	$fburl="https://feedburner.google.com/api/awareness/1.0/GetFeedData?uri=feed-id";
	$ch = curl_init();
	curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
	curl_setopt($ch, CURLOPT_URL, $fburl);
	$stored = curl_exec($ch);
	curl_close($ch);
	$grid = new SimpleXMLElement($stored);
	$rsscount = $grid->feed->entry['circulation'];
	echo $rsscount;
?>

Via: WpRecipes

Display The Latest Twitter Entry

Just paste this code in the template file (eg. sidebar.php) where you want to display the latest tweet.

<?php

// Your twitter username.
$username = "TwitterUsername";

$prefix = "<h2>My last Tweet</h2>";

$suffix = "";

$feed = "http://search.twitter.com/search.atom?q=from:" . $username . "&rpp=1";

function parse_feed($feed) {
    $stepOne = explode("<content type=\"html\">", $feed);
    $stepTwo = explode("</content>", $stepOne[1]);
    $tweet = $stepTwo[0];
    $tweet = str_replace("&lt;", "<", $tweet);
    $tweet = str_replace("&gt;", ">", $tweet);
    return $tweet;
}

$twitterFeed = file_get_contents($feed);
echo stripslashes($prefix) . parse_feed($twitterFeed) . stripslashes($suffix);
?>

Via: WpRecipes Credits: Ryan Barr

Social Buttons

Facebook Share Button

<a href="http://www.facebook.com/sharer.php?u=<?php the_permalink();?>&t=<?php the_title(); ?>">Share on Facebook</a>

Digg it

<a href="http://www.digg.com/submit?phase=2&url=<?php the_permalink();?>">Digg It</a>

Stumble upon it

<a href="http://www.stumbleupon.com/submit?url=<?php the_permalink(); ?>&title=<?php the_title(); ?>">Stumble upon it</a>

Add to delicious

<a href="http://delicious.com/post?url=<?php the_permalink();?>&title=<?php the_title();?>">Add to delicious</a>

Share on technorati

<a href="http://technorati.com/faves?sub=addfavbtn&add=<?php the_permalink();?>">Share on technorati</a>

Tweet this

<a href="http://twitter.com/home?status=Currently reading <?php the_permalink(); ?>">Tweet this</a>

Delicious Stumbleupon Digg