WordPress setting for URL permalinks structure

WordPress adjust category base.php

<?php
/** 
 * Changes WordPress posts URL structure, so that in results in following:
 * 
 * Articles overview:	/articles/
 * Category overview:	/articles/europe
 * Article detail:	/articles/europe/title
 * Tag detail:		/articles/tag/work
 * 
 * Requires following settings of Permalinks:
 * URL custom structure:	/articles/%category%/%postname%/
 * Category base:		articles/category
 * Tag base: 			articles/tag
 */
class adjustCategoryBase {

	public $prefix = 'articles';

	public function __construct() {

		// Refresh rules on activation/deactivation/category changes
		add_action('created_category',array($this, 'no_category_base_refresh_rules'));
		add_action('edited_category',array($this, 'no_category_base_refresh_rules'));
		add_action('delete_category',array($this, 'no_category_base_refresh_rules'));

		// Remove category base
		add_action('init', array($this, 'no_category_base_permastruct'));

		// Add our custom category rewrite rules
		add_filter('category_rewrite_rules', array($this, 'no_category_base_rewrite_rules'));
	}

	// Refresh rewrite rules
	public function no_category_base_refresh_rules() {
		global $wp_rewrite;
		$wp_rewrite->flush_rules();
	}

	// Remove category base
	function no_category_base_permastruct() {
		global $wp_rewrite;
		$permastruct = $wp_rewrite->extra_permastructs['category']['struct'];
		$new_permastruct = str_replace('/category','',$permastruct);
		// insert it to rules table
		$wp_rewrite->extra_permastructs['category']['struct'] = $new_permastruct;
	}

	// Add our custom category rewrite rules
	public function no_category_base_rewrite_rules($category_rewrite) {
		$category_rewrite=array();
		$categories=get_categories(array('hide_empty'=>false));
		foreach($categories as $category) {
			$category_nicename = $category->slug;
			if ( $category->parent == $category->cat_ID ) // recursive recursion
				$category->parent = 0;
			elseif ($category->parent != 0 )
				$category_nicename = get_category_parents( $category->parent, false, '/', true ) . $category_nicename;
			$category_rewrite[$this->prefix.'/('.$category_nicename.')/(?:feed/)?(feed|rdf|rss|rss2|atom)/?$'] = 'index.php?category_name=$matches[1]&feed=$matches[2]';
			$category_rewrite[$this->prefix.'/('.$category_nicename.')/page/?([0-9]{1,})/?$'] = 'index.php?category_name=$matches[1]&paged=$matches[2]';
			$category_rewrite[$this->prefix.'/('.$category_nicename.')/?$'] = 'index.php?category_name=$matches[1]';
		}

		return $category_rewrite;
	}
}

$adjustCategoryBase = new adjustCategoryBase;

?>