OOP in Plugins

abstraction-1.php

<div class='post' id='post-23'>
  <h2><?php the_title() ?></h2>  
  <div class='excerpt'>
    <?php 
      $content = get_the_content();
      if( strlen($content) < 250  ) {
        echo $content;
      }
      else {
        $content = substr( $content, 0, 250 );
        echo $content . '...';
      }
    ?>
  </div>
</div>

abstraction-2.php

<div class='post' id='post-23'>
  <h2><?php the_title() ?></h2>  
  <div class='excerpt'>
    <?php the_excerpt() ?>
  </div>
</div>

example1.php

<?php
/*
Plugin Name: Written By Awesome
Description: Adds a nice author tagline
Version: 1.0.0
Author: Daniel Pataki
Author URI: http://danielpataki.com
*/

class Written_By_Awesome {
  function __construct() {
    add_filter( 'the_content', array( $this, 'add_author_line_to_content' ) );
  }
  
  function add_author_line_to_content( $content ) {
    return $content . '<br> Written by someone awesome';
  }
  
}

$written_by_awesome = new Written_By_Awesome();

example2.php

<?php



class PostsByCommentBackend {
  function construct() {
    add_action( 'pre_get_posts', array( $this, 'backend_query' ) );
  }
  function backend_query( $query ) {
     if ( ! $query->is_admin() ) {
        $query->set( 'orderby', 'comment_count' );
        $query->set( 'order', 'DESC' );
    }
  }
}

class PostsByCommentFrontend {
  function construct() {
    add_action( 'pre_get_posts', array( $this, 'frontend_query' ) );
  }
  function frontend_query( $query ) {
     if ( $query->is_admin() ) {
        $query->set( 'orderby', 'comment_count' );
        $query->set( 'order', 'DESC' );
    }
  }
}

$backend = new PostsByCommentBackend();
$frontend = new PostsByCommentFrontend();

post.class.php

class Post {
  function get_excerpt( $content ) {
    if( strlen($content) < 250  ) {
      return $content;
    }
    else {
      $excerpt = substr( $content, 0, 250 );
      return $excerpt . '...';
    }
  }
  
  function the_excerpt( $content ) {
    echo get_excerpt( $content );
  }
  
  function the_title( $title ) {
    echo $title;
  }
}

post.class2.php

class Post {
  var $title;
  var $content;
  
  function __construct( $data ) {
    $this->title = $data['title'];  
    $this->title = $data['content'];
  }

  function get_excerpt() {
    if( strlen($this->content) < 250  ) {
      return $this->content;
    }
    else {
      $excerpt = substr( $content, 0, 250 );
      return $excerpt . '...';
    }
  }
  
  function the_excerpt() {
    echo $this->get_excerpt();
  }
  
  function the_title() {
    echo $this->title;
  }

}

$postdata = array(
  'title' => 'Post 1 Title',
  'content' => 'Content of Post 1' 
);

$post = new Post( $postdata );
$post->the_excerpt();