Send to Buffer on Publish/Scheduled Post

functions.php

/**
 * Buffer App Library
 */
session_start();
require_once(get_template_directory().'/includes/libraries/bufferapp/bufferapp.php');

/**
* Post to Buffer on Publish/Scheduled Publish
*/
function buffer_schedule($post_id) {

	// if draft_to_publish calls this
	if (is_object ($post_id)) {
		// we get an object
		$object = $post_id;
		$id = $object->ID;
	// if publish_future_post calls this
	} else {
		// we get an id
		$object = get_post($post_id);
		$id = $post_id;
	}

	// check post type
	$post_type = get_post_type($id);

	// only do this for posts
	if ( 'post' == $post_type) {
		// okay proceed
	} else {
		// otherwise do nothing
		return;
	}

	// now check if buffer is permitted; if true, we skip this post
	// (this is the ACF field "buffer_lock_post" we created earlier)
	if (get_field('buffer_lock_post', $id)) return

	session_start();

	// now let's construct an excerpt...
	// if we have a manual buffer_desc in our ACF field for this post, use that
	if (get_field('buffer_desc', $id)) {
		$post_excerpt = get_field('buffer_desc', $id);
	} else {
		// otherwise, we should use the_excerpt from the post
		$post_excerpt = apply_filters('the_excerpt', get_post_field('post_excerpt', $id));
		// if there is no excerpt, we use the post title
		if (!$post_excerpt) $post_excerpt = $post_title;
	}

	// get the featured thumbnail
        $thumbnail_id = get_post_thumbnail_id($id);
	if ($thumbnail_id) {
		$thumbnail = wp_get_attachment_image_src( $thumbnail_id, 'post-thumbnail' );
	} else {
		$thumbnail = false;
	}

	// construct media array for buffer
	$media = array(
		'link'=> get_permalink($id),
		'description'=>$post_excerpt,
		'title'=>$post_excerpt,
		'picture'=>$thumbnail,
		'photo'=>$thumbnail,
		'thumbnail'=>$thumbnail
	);

	// by default, we'll attach categories as our hash tags
	// first, we check if there are any manually-entered hash tags
	// (this is the hash_tags ACF field we created earlier)
	if (get_field('hash_tags', $id)) {
		$term_list = get_field('hash_tags', $id);
	} else {
		// otherwise, let's get category terms
		// this will construct a list of hashtags like #term #term #term
		// using the slug of each term
		$term_list = '';
		$terms = get_the_terms($id, 'category');
		$count = count($terms);
		if ( $count > 0 ) {
			foreach ( $terms as $i=>$term ) {
				$hash_name = $term->slug;
				if ($i < $count-1) {
					$term_list .= '#'.$hash_name . " ";
				} else {
					$term_list .= '#'.$hash_name;
				}
				
			}
		}
	}

	// construct short link to inject into our sharing copy
	// we'll use this as the link to share with buffer
	$url = get_site_url().'/?p='.$id;

	// construct text to be shared
	$text = $post_excerpt . ' - ' .$url;

	// start a new buffer instance
	$buffer = new \BufferApp(BUFFER_CLIENT_ID, BUFFER_CLIENT_SECRET, null);

	// specify which profiles to queue to
	// you can find these IDs by looking at the URL when you one of your profiles
	// https://buffer.com/app/profile/YOUR_PROFILE_ID/buffer/queue/list
	$profiles = array(
		'PUT YOUR LINKEDIN BUFFER PROFILE ID HERE', // linkedin
		'PUT YOUR GOOGLE PLUS PROFILE ID HERE', // gplus
		'PUT YOUR FACEBOOK PROFILE ID HERE', // fb
		'PUT YOUR TWITTER PROFILE ID HERE', // twitter
	);

	foreach($profiles as $profile){
		// only certain profiles support hashtags, so let's only append our $term_list to those profiles
		if ($profile == 'PUT YOUR TWITTER PROFILE ID HERE' || $profile == 'PUT YOUR FACEBOOK PROFILE ID HERE') {
			$text = $post_excerpt . ' - '. $url . ' '.$term_list;
		} else {
			$text = $text;
		}
		$buffer->go('/updates/create', array(
			'text' => strip_tags($text),
			'media[title]'=> strip_tags(get_the_title($id)),
			'media[link]'=> get_permalink($id),
			'media[description]'=> strip_tags($post_excerpt),
			'media[picture]'=>  $thumbnail,
			'media[thumbnail]'=> $thumbnail,
			'profile_ids[]' => $profile
		));
	}

	// then, we need to lock this post from being posted to buffer in the future
	// you'll need to get the field ID of your buffer_lock_post field, and enter it here
	update_field('ENTER FIELD ID FOR BUFFER_LOCK_POST', 1, $id);

}
add_action('publish_future_post', 'buffer_schedule');
add_action('draft_to_publish', 'buffer_schedule', 10, 2 );