How to replace meta title and meta description in wordpress? - php

Question

Sorry if my question was basic or stupid but please help me to solve this issue. I'm trying to change <title> and <meta name="description" > tags dynamically in wordpress. so this is what I tried in function.php file.
function changeMeta_2(){
global $wpdb;
$cur_url = $_SERVER['REQUEST_URI'];
$basename = pathinfo($cur_url);
$ebasename = $basename['filename'];
if(is_numeric($ebasename)) {
$url = explode('/', $basename['dirname']);
$basename = explode('.', $url[count($url)-2]);
$ebasename = $basename[0];
}
$pageName = $ebasename;
$arraylist_subcat = array("car","bike","boat","xxxx","yyyy","zzz","mmmm");
$arraylist_maincat = array("aus","ind","usa","uae");
$category_id = get_term_by('slug',$pageName, 'category');
$category_parentid = get_term_by('id', $category_id->parent, 'category');
$parent_slug = $category_parentid->slug;
if ( is_page()) {
if ( in_array($pageName,$arraylist_maincat) ) {
$metaTitle = 'Browse '.$pageName.' | Some txt title | mysite.com';
$metaDescription = 'some of custome blablaaaaa text description '.$pageName.' some of custome blablaaaaa text description ';
echo '<title>'.$metaTitle.'</title>';
echo '<meta name="description" content="'.$metaDescription.'"/>';
}
}
}
add_action( 'wp_head', 'changeMeta_2' );
In the above code I'm trying to change the title tag and meta description for term id which are matching with array values (in_array condition).
Everything works fine, but problem is instead of override(replace) <title> tag is appending in head. Its not changing it appending. please someone help me to solve this issue.

Answer 1

How document title is generated has changed since Wordpress v4.4.0. Now wp_get_document_title dictates how title is generated:
/**
* Displays title tag with content.
*
* #ignore
* #since 4.1.0
* #since 4.4.0 Improved title output replaced `wp_title()`.
* #access private
*/
function _wp_render_title_tag() {
if ( ! current_theme_supports( 'title-tag' ) ) {
return;
}
echo '<title>' . wp_get_document_title() . '</title>' . "\n";
}
Here is the code from v5.4.2. Here are the filters you can use to manipulate title tag:
function wp_get_document_title() {
/**
* Filters the document title before it is generated.
*
* Passing a non-empty value will short-circuit wp_get_document_title(),
* returning that value instead.
*
* #since 4.4.0
*
* #param string $title The document title. Default empty string.
*/
$title = apply_filters( 'pre_get_document_title', '' );
if ( ! empty( $title ) ) {
return $title;
}
// --- snipped ---
/**
* Filters the separator for the document title.
*
* #since 4.4.0
*
* #param string $sep Document title separator. Default '-'.
*/
$sep = apply_filters( 'document_title_separator', '-' );
/**
* Filters the parts of the document title.
*
* #since 4.4.0
*
* #param array $title {
* The document title parts.
*
* #type string $title Title of the viewed page.
* #type string $page Optional. Page number if paginated.
* #type string $tagline Optional. Site description when on home page.
* #type string $site Optional. Site title when not on home page.
* }
*/
$title = apply_filters( 'document_title_parts', $title );
// --- snipped ---
return $title;
}
So here are two ways you can do it.
First one uses pre_get_document_title filter which short-circuits the title generation and hence more performant if you are not going make changes on current title:
function custom_document_title( $title ) {
return 'Here is the new title';
}
add_filter( 'pre_get_document_title', 'custom_document_title', 10 );
Second way uses document_title_separator and document_title_parts hooks for the title and the title seperator that are executed later in the function, after title is generated using functions like single_term_title or post_type_archive_title depending on the page and about to be outputted:
// Custom function should return a string
function custom_seperator( $sep ) {
return '>';
}
add_filter( 'document_title_separator', 'custom_seperator', 10 );
// Custom function should return an array
function custom_html_title( $title ) {
return array(
'title' => 'Custom Title',
'site' => 'Custom Site'
);
}
add_filter( 'document_title_parts', 'custom_html_title', 10 );

Answer 2

For anybody coming to this question in the future: This functionality can be accomplished using the Yoast SEO plugin.
However, if you do want to still do this yourself....
In order to modify the title, rather than the wp_head hook, you need to be using the filters that actually allow you to modify the title: wp_title
And you can / should use the wp_head in order to add the meta description (see the docs here: http://codex.wordpress.org/Meta_Tags_in_WordPress)
Also note there's easier ways to get the page title, mentioned below...
For the title, your code would look something like so:
function changeTitle($title, $sep, $seplocation){
global $wpdb;
// NOTE: This is the HARD way to get the page title, and is unreliable...
$cur_url = $_SERVER['REQUEST_URI'];
$basename = pathinfo($cur_url);
$ebasename = $basename['filename'];
if(is_numeric($ebasename)) {
$url = explode('/', $basename['dirname']);
$basename = explode('.', $url[count($url)-2]);
$ebasename = $basename[0];
}
$pageName = $ebasename;
// NOTE: Why not get pagename this way?
global $post;
$pageName = $post->post_title;
// or if you need the slug...
$pageName = $post->post_slug;
$arraylist_subcat = array("car","bike","boat","xxxx","yyyy","zzz","mmmm");
$arraylist_maincat = array("aus","ind","usa","uae");
$category_id = get_term_by('slug',$pageName, 'category');
$category_parentid = get_term_by('id', $category_id->parent, 'category');
$parent_slug = $category_parentid->slug;
if ( is_page()) {
if ( in_array($pageName,$arraylist_maincat) ) {
$title = 'Browse '.$pageName.' | Some txt title | mysite.com';
}
}
return $title;
}
add_action( 'wp_title', 'changeTitle', 10, 3 );