How to make my own while Loop just like Wordpress

Question

im new here and new in PHP too..

Just wondering how to make my own flexible loop just like in Wordpress... Note im not talking about wordpress.. I want to implement it on myown PHP application...

let's look back in WP, there is a code something like this:

while (have_post() : thepost())// .. bla bla...

echo the_title();
echo the_content();

endwhile; // this is just an ilustration

Could you figure out how have_post() or the_post() interact with database, so that they can be loop..

thanks..

Answer 1

WordPress uses global variables that these functions modify when iterating through the loop. e.g.:

var $posts = null;
var $post = null;
var $post_count = 0;
var $post_index = 0;

function have_post() {
    global $posts, $post_count, $post_index;

    $post_index = 0;

    // do a database call to retrieve the posts.
    $posts = mysql_query('select * from posts where ...');

    if ($posts) {
        $post_count = count($posts);
        return true;
    } else {
        $post_count = 0;
        return false;
    }
}

function thepost() {
    global $posts, $post, $post_count, $post_index;

    // make sure all the posts haven't already been looped through
    if ($post_index > $post_count) {
        return false;
    }

    // retrieve the post data for the current index
    $post = $posts[$post_index];

    // increment the index for the next time this method is called
    $post_index++;

    return $post;
}

function the_title() {
    global $post;
    return $post['title'];
}

function the_content() {
    global $post;
    return $post['content'];
}

I would definitely recommend using OOP style coding over what WordPress does, however. This will keep variables definied within an instance of an object instead of being globally accessible. e.g.:

class Post {
    function __construct($title, $content) {
        $this->title = $title;
        $this->content = $content;
    }

    function getTitle() {
        return $title;
    }

    function getContent() {
        return $content;
    }
}

class Posts {
    var $postCount = 0;
    var $posts = null;

    function __construct($conditions) {
        $rs = mysql_query('select * from posts where $conditions...');

        if ($rs) {
            $this->postCount = count($rs);
            $this->posts = array();

            foreach ($rs as $row) {
                $this->posts[] = new Post($row['title'], $row['content']);
            }
        }
    }

    function getPostCount() {
        return $this->postCount;
    }

    function getPost($index) {
        return $this->posts[$index];
    }
}

Answer 2

Go to this problem again :D

finally I got the solution,

@Matt Huggins, i have made some revision to your code, and now it's work...

$posts = $wpdb->get_results('SELECT * FROM my_table',OBJECT);
$post = null;
$post_count = 0;
$post_index = 0;

function have_post() {
    global $posts, $post_count, $post_index;

    if ($posts && ($post_index <= $post_count)){
        $post_count = count($posts);
        return true;
    }
    else {
        $post_count = 0;
        return false;
    }
}

function the_post() {
    global $posts, $post, $post_count, $post_index;

    // make sure all the posts haven't already been looped through
    if ($post_index > $post_count) {
        return false;
    }

    // retrieve the post data for the current index
    $post = $posts[$post_index+1];

    // increment the index for the next time this method is called
    $post_index++;
    return $post;

}

function the_title() {
    global $post;
    return $post->Title;
}

function the_content() {
    global $post;
    return $post->Content;
}

//and the output

if(have_post()) : while(have_post()) : the_post();
echo '<h2>'.the_title().'</h2>';
echo '<p>'.the_content().'</p>';
endwhile; endif;

Many thanks... :)

Answer 3

the idea is to use global scope variables, and then the functions will modify those variables:

// first define the global variables:
$post_index = 0;
$posts_count = 0;
$post = null;
$posts = null;
$connection = null;

$connection = new PDO('mysql:host=127.0.0.1;dbname=YOUR_DB', 'YOUR_DB_USERNAME', 'YOUR_DB_USER_PASSWORD', array(PDO::ATTR_FETCH_MODE => PDO::FETCH_ASSOC));

$query = $connection->query('SELECT * FROM posts');
$posts = $query->fetchAll();

$posts_count = count($posts); // or = $query->rowCount()

// now you create the functions that will deal with and change those variables

function have_posts()
{
    global $post_index, $posts_count, $posts, $post;
    // if posts found and if post_index < posts_count return true else return false
    if($posts && $post_index < $post_count)
        return true;

    else
        return false;
}

function the_post()
{
    global $post_count, $post_index, $posts, $post;

    if($post_index > $post_count)
        return false;
    // fetch the post of the current index
    $post = $posts[$post_index];

    // increment the $post_index so that the next call to this function grapes the next post
    $post_index++;
}

function get_ID()
{
    global $post;
    return $post['ID'];
}


function get_title()
{
    global $post;
    return $post['title'];
}

I hope that help.

Answer 4

You could implement the Iterator interface.