Creating Your Own WordPress Metabox. Attaching a PDF file to an article.

by Nikolaenko Maxim · Published October 25, 2012 · Updated August 10, 2018

Create your own metabox WordPress, we fix PDF file by article. It is very convenient to use additional fields when developing a plugin. “metabox“.

To get started, you need to download WordPress PDF file. After downloading, open the function.php file and paste the code there:

add_action("admin_init", "pdf_init");
add_action('save_post', 'save_pdf_link');
function pdf_init(){
	add_meta_box("my-pdf", "PDF Document", "pdf_link", "post", "normal", "low");
	}
function pdf_link(){
	global $post;
	$custom  = get_post_custom($post->ID);
	$link    = $custom["link"][0];
	$count   = 0;
	echo '<div class="link_header">';
	$query_pdf_args = array(
		'post_type' => 'attachment',
		'post_mime_type' =>'application/pdf',
		'post_status' => 'inherit',
		'posts_per_page' => -1,
		);
	$query_pdf = new WP_Query( $query_pdf_args );
	$pdf = array();
	echo '<select name="link">';
	echo '<option class="pdf_select">SELECT pdf FILE</option>';
	foreach ( $query_pdf->posts as $file) {
	   if($link == $pdf[]= $file->guid){
	      echo '<option value="'.$pdf[]= $file->guid.'" selected="true">'.$pdf[]= $file->guid.'</option>';
		 }else{
	      echo '<option value="'.$pdf[]= $file->guid.'">'.$pdf[]= $file->guid.'</option>';
		 }
		$count++;
	}
	echo '</select><br /></div>';
	echo '<p>Selecting a pdf file from the above list to attach to this post.</p>';
	echo '<div class="pdf_count"><span>Files:</span> <b>'.$count.'</b></div>';
}
function save_pdf_link(){
	global $post;
	if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE){ return $post->ID; }
	update_post_meta($post->ID, "link", $_POST["link"]);
}
add_action( 'admin_head', 'pdf_css' );
function pdf_css() {
	echo '<style type="text/css">
	.pdf_select{
		font-weight:bold;
		background:#e5e5e5;
		}
	.pdf_count{
		font-size:9px;
		color:#0066ff;
		text-transform:uppercase;
		background:#f3f3f3;
		border-top:solid 1px #e5e5e5;
		padding:6px 6px 6px 12px;
		margin:0px -6px -8px -6px;
		-moz-border-radius:0px 0px 6px 6px;
		-webkit-border-radius:0px 0px 6px 6px;
		border-radius:0px 0px 6px 6px;
		}
	.pdf_count span{color:#666;}
		</style>';
}
function pdf_file_url(){
	global $wp_query;
	$custom = get_post_custom($wp_query->post->ID);
	echo $custom['link'][0];
}

add_action("admin_init", "pdf_init");

add_action('save_post', 'save_pdf_link');

function pdf_init(){

add_meta_box("my-pdf", "PDF Document", "pdf_link", "post", "normal", "low");

}

function pdf_link(){

global $post;

$custom = get_post_custom($post->ID);

$link = $custom["link"][0];

$count = 0;

echo '<div class="link_header">';

$query_pdf_args = array(

'post_type' => 'attachment',

'post_mime_type' =>'application/pdf',

'post_status' => 'inherit',

'posts_per_page' => -1,

);

$query_pdf = new WP_Query( $query_pdf_args );

$pdf = array();

echo '<select name="link">';

echo '<option class="pdf_select">SELECT pdf FILE</option>';

foreach ( $query_pdf->posts as $file) {

if($link == $pdf[]= $file->guid){

echo '<option value="'.$pdf[]= $file->guid.'" selected="true">'.$pdf[]= $file->guid.'</option>';

}else{

echo '<option value="'.$pdf[]= $file->guid.'">'.$pdf[]= $file->guid.'</option>';

}

$count++;

}

echo '</select><br /></div>';

echo '<p>Selecting a pdf file from the above list to attach to this post.</p>';

echo '<div class="pdf_count"><span>Files:</span> <b>'.$count.'</b></div>';

}

function save_pdf_link(){

global $post;

if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE){ return $post->ID; }

update_post_meta($post->ID, "link", $_POST["link"]);

}

add_action( 'admin_head', 'pdf_css' );

function pdf_css() {

echo '<style type="text/css">

.pdf_select{

font-weight:bold;

background:#e5e5e5;

}

.pdf_count{

font-size:9px;

color:#0066ff;

text-transform:uppercase;

background:#f3f3f3;

border-top:solid 1px #e5e5e5;

padding:6px 6px 6px 12px;

margin:0px -6px -8px -6px;

-moz-border-radius:0px 0px 6px 6px;

-webkit-border-radius:0px 0px 6px 6px;

border-radius:0px 0px 6px 6px;

}

.pdf_count span{color:#666;}

</style>';

}

function pdf_file_url(){

global $wp_query;

$custom = get_post_custom($wp_query->post->ID);

echo $custom['link'][0];

}

Next, go to the section for creating a new article and scroll to the bottom of the page. In the metabox that appears, in the drop down list, select the downloaded file.

You can get the address like this:

<? pdf_file_url(); ?>

1	<? pdf_file_url(); ?>

An example of using an uploaded file:

<a href="<? pdf_file_url(); ?>">My PDF File</a>

1	<a href="<? pdf_file_url(); ?>">My PDF File</a>

Code checked, everything works perfectly. Good luck with development.

Online tutoring services. List of courses I teach

Basic web design course;
Site layout;
General course on CMS WordPress and continuation of the course on template development;
Website development in PHP.