/api/simpler_db.php

<?php
class SimplerDB {

	private $access_key;
	private $secret_key;

	function __construct($access_key, $secret_key, $domain = null) {
		$this->access_key = $access_key;
		$this->secret_key = $secret_key;
		$this->params = array(
			'AWSAccessKeyId'   => $this->access_key,
			'Version'          => '2009-04-15',
			'ZoneName.0'       => 'us-east-1a',
			'ZoneName.1'       => 'us-east-1b',
			'ZoneName.2'       => 'us-east-1c',
			'SignatureVersion' => 2,
			'SignatureMethod'  => 'HmacSHA256'
		);
	}
	
	function __call($name, $args) {
		return $this->request(ucfirst($name), count($args) > 0 ? $args[0] : array());
	}
	
	function uuid($prefix = '') {
		$chars = uniqid(md5(mt_rand()), true);
		$uuid  = substr($chars, 0, 8) . '-';
		$uuid .= substr($chars, 8, 4) . '-';
		$uuid .= substr($chars, 12, 4) . '-';
		$uuid .= substr($chars, 16, 4) . '-';
		$uuid .= substr($chars, 20, 12);
		return $prefix . $uuid;
	}
	
	function batchPutAttributes($items, $params = array()) {
		$params = array_merge($this->itemsToParams($items), $params);
		return $this->request('BatchPutAttributes', $params);
	}
	
	/*
	function deleteAttributes($items, $params = array()) {
		$params = array_merge($this->itemsToParams($items), $params);
		return $this->request('DeleteAttributes', $params);
	}
	*/
	
	private function itemsToParams($items) {
		$params = array();
		$item_no = 0;
		foreach ($items as $item => $attributes) {
			$attr_no = 0;
			$params["Item.{$item_no}.ItemName"] = $item;
			foreach ($attributes as $name => $value) {
				$params["Item.{$item_no}.Attribute.{$attr_no}.Name"] = $name;
				$params["Item.{$item_no}.Attribute.{$attr_no}.Value"] = $value;
				$attr_no++;
			}
			$item_no++;
		}
		return $params;
	}
	
	private function request($action, $qs_params = array()) {
		// Make sure extra query string params are factored in
		foreach ($qs_params as $key => $value) {
			$this->params[$key] = $value;
		}
		// Add a timestamp
		$this->params['Timestamp'] = gmdate('Y-m-d\TH:i:s\Z');
		$this->params['Action'] = $action;
		// Generate a version 2 signature
		uksort($this->params, 'strnatcmp');
		$qstr = '';
		foreach ($this->params as $key => $value) {
    		$qstr .= '&'.$key.'='.rawurlencode($value);
		}
		$qstr = substr($qstr, 1);
		$signature_v2 = "GET\nsdb.amazonaws.com\n/\n{$qstr}";
		$this->params['Signature'] = base64_encode(hash_hmac('sha256', $signature_v2, $this->secret_key, true));
		// Send cURL call
		$ch = curl_init();
		$request_url = 'https://sdb.amazonaws.com/?'.http_build_query($this->params);
		//echo $request_url . "<br />";
		curl_setopt($ch, CURLOPT_URL, $request_url);
		curl_setopt($ch, CURLOPT_HEADER, 0);
		curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
		$response = curl_exec($ch);
		return $response;
	}

}