helper.php

<?php

require_once('json-utils.php');

abstract class DbData {
	abstract public function loadFromRow($row);

	public static function match($template) {
		$params = array();
		$pathInfo = $_SERVER['PATH_INFO'];
		
		while (true) {
			$pos = strpos($template, "{");
			if ($pos === FALSE) {
				if ($pathInfo == $template) {
					return $params;
				} else {
					return FALSE;
				}
			}
			$extractA = substr($pathInfo, 0, $pos);
			$extractB = substr($template, 0, $pos);
			if ($extractA != $extractB) {
				return FALSE;
			}
			
			// Extract the variable name
			$template = substr($template, $pos + 1);
			$pathInfo = substr($pathInfo, $pos);

			$endPos = strpos($template, "}");
			$varName = substr($template, 0, $endPos);
			$template = substr($template, $endPos + 1);

			// Find the next section
			$nextPos = strpos($template, "{");
			$nextExtract = ($nextPos === FALSE) ? $template : substr($template, 0, $nextPos);
			
			if ($nextExtract == "") {
				$params[$varName] = $pathInfo;
				return $params;
			}
			
			$endOfValuePos = strpos($pathInfo, $nextExtract);
			if ($endOfValuePos === FALSE) {
				return FALSE;
			}
			$value = substr($pathInfo, 0, $endOfValuePos);
			$params[$varName] = $value;
			
			$pathInfo = substr($pathInfo, $endOfValuePos);
		}
	}
}

?>

index.php

<?php

require_once('config.php');
$db = new mysqli(MYSQL_ADDRESS, MYSQL_USERNAME, MYSQL_PASSWORD, MYSQL_DATABASENAME);

require_once 'helper.php';

class TestItems extends DbData {
	public static function open($id) {
		global $db;
		$item = new TestItems;
		
		$id = $db->escape_string($id);
		$sql = "SELECT * FROM helper_items WHERE id='{$id}'";
		$result = $db->query($sql) or json_error($db->error);
		
		if (!($row = $result->fetch_assoc())) {
			json_error("Item not found", 404);
		}
		$item->loadFromRow($row);
		
		return $item;
	}
	
	public function loadFromRow($row) {
		$this->id = (int)$row['id'];
		$this->title = $row['title'];
		$this->message = $row['message'];
		$this->posted = $row['posted'];
	}
}

if ($params = DbData::match("/items/{id}/")) {
	$item = TestItems::open($params['id']);
	json_exit($item);
}

json_error("No URL match found");

?>