diff --git a/client.php b/client.php
new file mode 100644
index 0000000..4fc6c1d
--- /dev/null
+++ b/client.php
@@ -0,0 +1,12 @@
+<?php
+
+require_once('oai2client.php');
+
+$client = new OAI2Client('http://localhost/~daniel/2moodle/local/oai_pmh/moodle.php');
+
+var_dump($client->Identify());
+var_dump($client->ListMetadataFormats());
+var_dump($client->ListSets());
+var_dump($client->ListIdentifiers(array('metadataPrefix' => 'oai_dc')));
+var_dump($client->ListRecords(array('metadataPrefix' => 'oai_dc')));
+var_dump($client->GetRecord('aaaaa', 'oai_dc'));
diff --git a/curl.php b/curl.php
new file mode 100644
index 0000000..a6ab568
--- /dev/null
+++ b/curl.php
@@ -0,0 +1,622 @@
+<?php
+/**
+ * cURL class
+ *
+ * This is a wrapper class for curl, it is quite easy to use:
+ * <code>
+ * $c = new curl;
+ * // enable cache
+ * $c = new curl(array('cache'=>true));
+ * // enable cookie
+ * $c = new curl(array('cookie'=>true));
+ * // enable proxy
+ * $c = new curl(array('proxy'=>true));
+ *
+ * // HTTP GET Method
+ * $html = $c->get('http://example.com');
+ * // HTTP POST Method
+ * $html = $c->post('http://example.com/', array('q'=>'words', 'name'=>'moodle'));
+ * // HTTP PUT Method
+ * $html = $c->put('http://example.com/', array('file'=>'/var/www/test.txt');
+ * </code>
+ *
+ * @author     Dongsheng Cai <dongsheng@moodle.com> - https://github.com/dongsheng/cURL
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU Public License
+ */
+
+class curl {
+    /** @var bool */
+    public  $cache    = false;
+    public  $proxy    = false;
+    /** @var array */
+    public  $response = array();
+    public  $header   = array();
+    /** @var string */
+    public  $info;
+    public  $error;
+
+    /** @var array */
+    private $options;
+    /** @var string */
+    private $proxy_host = '';
+    private $proxy_auth = '';
+    private $proxy_type = '';
+    /** @var bool */
+    private $debug    = false;
+    private $cookie   = false;
+
+    /**
+     * @param array $options
+     */
+    public function __construct($options = array()){
+        if (!function_exists('curl_init')) {
+            $this->error = 'cURL module must be enabled!';
+            trigger_error($this->error, E_USER_ERROR);
+            return false;
+        }
+        // the options of curl should be init here.
+        $this->resetopt();
+        if (!empty($options['debug'])) {
+            $this->debug = true;
+        }
+        if(!empty($options['cookie'])) {
+            if($options['cookie'] === true) {
+                $this->cookie = 'curl_cookie.txt';
+            } else {
+                $this->cookie = $options['cookie'];
+            }
+        }
+        if (!empty($options['cache'])) {
+            if (class_exists('curl_cache')) {
+                $this->cache = new curl_cache();
+            }
+        }
+    }
+    /**
+     * Resets the CURL options that have already been set
+     */
+    public function resetopt(){
+        $this->options = array();
+        $this->options['CURLOPT_USERAGENT']         = 'MoodleBot/1.0';
+        // True to include the header in the output
+        $this->options['CURLOPT_HEADER']            = 0;
+        // True to Exclude the body from the output
+        $this->options['CURLOPT_NOBODY']            = 0;
+        // TRUE to follow any "Location: " header that the server
+        // sends as part of the HTTP header (note this is recursive,
+        // PHP will follow as many "Location: " headers that it is sent,
+        // unless CURLOPT_MAXREDIRS is set).
+        //$this->options['CURLOPT_FOLLOWLOCATION']    = 1;
+        $this->options['CURLOPT_MAXREDIRS']         = 10;
+        $this->options['CURLOPT_ENCODING']          = '';
+        // TRUE to return the transfer as a string of the return
+        // value of curl_exec() instead of outputting it out directly.
+        $this->options['CURLOPT_RETURNTRANSFER']    = 1;
+        $this->options['CURLOPT_BINARYTRANSFER']    = 0;
+        $this->options['CURLOPT_SSL_VERIFYPEER']    = 0;
+        $this->options['CURLOPT_SSL_VERIFYHOST']    = 2;
+        $this->options['CURLOPT_CONNECTTIMEOUT']    = 30;
+    }
+
+    /**
+     * Reset Cookie
+     */
+    public function resetcookie() {
+        if (!empty($this->cookie)) {
+            if (is_file($this->cookie)) {
+                $fp = fopen($this->cookie, 'w');
+                if (!empty($fp)) {
+                    fwrite($fp, '');
+                    fclose($fp);
+                }
+            }
+        }
+    }
+
+    /**
+     * Set curl options
+     *
+     * @param array $options If array is null, this function will
+     * reset the options to default value.
+     *
+     */
+    public function setopt($options = array()) {
+        if (is_array($options)) {
+            foreach($options as $name => $val){
+                if (stripos($name, 'CURLOPT_') === false) {
+                    $name = strtoupper('CURLOPT_'.$name);
+                }
+                $this->options[$name] = $val;
+            }
+        }
+    }
+    /**
+     * Reset http method
+     *
+     */
+    public function cleanopt(){
+        unset($this->options['CURLOPT_HTTPGET']);
+        unset($this->options['CURLOPT_POST']);
+        unset($this->options['CURLOPT_POSTFIELDS']);
+        unset($this->options['CURLOPT_PUT']);
+        unset($this->options['CURLOPT_INFILE']);
+        unset($this->options['CURLOPT_INFILESIZE']);
+        unset($this->options['CURLOPT_CUSTOMREQUEST']);
+    }
+
+    /**
+     * Set HTTP Request Header
+     *
+     * @param array $headers
+     *
+     */
+    public function setHeader($header) {
+        if (is_array($header)){
+            foreach ($header as $v) {
+                $this->setHeader($v);
+            }
+        } else {
+            $this->header[] = $header;
+        }
+    }
+    /**
+     * Set HTTP Response Header
+     *
+     */
+    public function getResponse(){
+        return $this->response;
+    }
+    /**
+     * private callback function
+     * Formatting HTTP Response Header
+     *
+     * @param mixed $ch Apparently not used
+     * @param string $header
+     * @return int The strlen of the header
+     */
+    private function formatHeader($ch, $header)
+    {
+        $this->count++;
+        if (strlen($header) > 2) {
+            list($key, $value) = explode(" ", rtrim($header, "\r\n"), 2);
+            $key = rtrim($key, ':');
+            if (!empty($this->response[$key])) {
+                if (is_array($this->response[$key])){
+                    $this->response[$key][] = $value;
+                } else {
+                    $tmp = $this->response[$key];
+                    $this->response[$key] = array();
+                    $this->response[$key][] = $tmp;
+                    $this->response[$key][] = $value;
+
+                }
+            } else {
+                $this->response[$key] = $value;
+            }
+        }
+        return strlen($header);
+    }
+
+    /**
+     * Set options for individual curl instance
+     *
+     * @param object $curl A curl handle
+     * @param array $options
+     * @return object The curl handle
+     */
+    private function apply_opt($curl, $options) {
+        // Clean up
+        $this->cleanopt();
+        // set cookie
+        if (!empty($this->cookie) || !empty($options['cookie'])) {
+            $this->setopt(array('cookiejar'=>$this->cookie,
+                            'cookiefile'=>$this->cookie
+                             ));
+        }
+
+        // set proxy
+        if (!empty($this->proxy) || !empty($options['proxy'])) {
+            $this->setopt($this->proxy);
+        }
+        $this->setopt($options);
+        // reset before set options
+        curl_setopt($curl, CURLOPT_HEADERFUNCTION, array(&$this,'formatHeader'));
+        // set headers
+        if (empty($this->header)){
+            $this->setHeader(array(
+                'User-Agent: MoodleBot/1.0',
+                'Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7',
+                'Connection: keep-alive'
+                ));
+        }
+        curl_setopt($curl, CURLOPT_HTTPHEADER, $this->header);
+
+        if ($this->debug){
+            echo '<h1>Options</h1>';
+            var_dump($this->options);
+            echo '<h1>Header</h1>';
+            var_dump($this->header);
+        }
+
+        // set options
+        foreach($this->options as $name => $val) {
+            if (is_string($name)) {
+                $name = constant(strtoupper($name));
+            }
+            curl_setopt($curl, $name, $val);
+        }
+        return $curl;
+    }
+    /**
+     * Download multiple files in parallel
+     *
+     * Calls {@link multi()} with specific download headers
+     *
+     * <code>
+     * $c = new curl;
+     * $c->download(array(
+     *              array('url'=>'http://localhost/', 'file'=>fopen('a', 'wb')),
+     *              array('url'=>'http://localhost/20/', 'file'=>fopen('b', 'wb'))
+     *              ));
+     * </code>
+     *
+     * @param array $requests An array of files to request
+     * @param array $options An array of options to set
+     * @return array An array of results
+     */
+    public function download($requests, $options = array()) {
+        $options['CURLOPT_BINARYTRANSFER'] = 1;
+        $options['RETURNTRANSFER'] = false;
+        return $this->multi($requests, $options);
+    }
+    /*
+     * Mulit HTTP Requests
+     * This function could run multi-requests in parallel.
+     *
+     * @param array $requests An array of files to request
+     * @param array $options An array of options to set
+     * @return array An array of results
+     */
+    protected function multi($requests, $options = array()) {
+        $count   = count($requests);
+        $handles = array();
+        $results = array();
+        $main    = curl_multi_init();
+        for ($i = 0; $i < $count; $i++) {
+            $url = $requests[$i];
+            foreach($url as $n=>$v){
+                $options[$n] = $url[$n];
+            }
+            $handles[$i] = curl_init($url['url']);
+            $this->apply_opt($handles[$i], $options);
+            curl_multi_add_handle($main, $handles[$i]);
+        }
+        $running = 0;
+        do {
+            curl_multi_exec($main, $running);
+        } while($running > 0);
+        for ($i = 0; $i < $count; $i++) {
+            if (!empty($options['CURLOPT_RETURNTRANSFER'])) {
+                $results[] = true;
+            } else {
+                $results[] = curl_multi_getcontent($handles[$i]);
+            }
+            curl_multi_remove_handle($main, $handles[$i]);
+        }
+        curl_multi_close($main);
+        return $results;
+    }
+    /**
+     * Single HTTP Request
+     *
+     * @param string $url The URL to request
+     * @param array $options
+     * @return bool
+     */
+    protected function request($url, $options = array()){
+        // create curl instance
+        $curl = curl_init($url);
+        $options['url'] = $url;
+        $this->apply_opt($curl, $options);
+        if ($this->cache && $ret = $this->cache->get($this->options)) {
+            return $ret;
+        } else {
+            $ret = curl_exec($curl);
+            if ($this->cache) {
+                $this->cache->set($this->options, $ret);
+            }
+        }
+
+        $this->info  = curl_getinfo($curl);
+        $this->error = curl_error($curl);
+
+        if ($this->debug){
+            echo '<h1>Return Data</h1>';
+            var_dump($ret);
+            echo '<h1>Info</h1>';
+            var_dump($this->info);
+            echo '<h1>Error</h1>';
+            var_dump($this->error);
+        }
+
+        curl_close($curl);
+
+        if (empty($this->error)){
+            return $ret;
+        } else {
+            return $this->error;
+            // exception is not ajax friendly
+            //throw new moodle_exception($this->error, 'curl');
+        }
+    }
+
+    /**
+     * HTTP HEAD method
+     *
+     * @see request()
+     *
+     * @param string $url
+     * @param array $options
+     * @return bool
+     */
+    public function head($url, $options = array()){
+        $options['CURLOPT_HTTPGET'] = 0;
+        $options['CURLOPT_HEADER']  = 1;
+        $options['CURLOPT_NOBODY']  = 1;
+        return $this->request($url, $options);
+    }
+
+    /**
+     * Recursive function formating an array in POST parameter
+     * @param array $arraydata - the array that we are going to format and add into &$data array
+     * @param string $currentdata - a row of the final postdata array at instant T
+     *                when finish, it's assign to $data under this format: name[keyname][][]...[]='value'
+     * @param array $data - the final data array containing all POST parameters : 1 row = 1 parameter
+     */
+    function format_array_postdata_for_curlcall($arraydata, $currentdata, &$data) {
+        foreach ($arraydata as $k=>$v) {
+            $newcurrentdata = $currentdata;
+            if (is_object($v)) {
+                $v = (array) $v;
+            }
+            if (is_array($v)) { //the value is an array, call the function recursively
+                $newcurrentdata = $newcurrentdata.'['.urlencode($k).']';
+                $this->format_array_postdata_for_curlcall($v, $newcurrentdata, $data);
+            }  else { //add the POST parameter to the $data array
+                $data[] = $newcurrentdata.'['.urlencode($k).']='.urlencode($v);
+            }
+        }
+    }
+
+    /**
+     * Transform a PHP array into POST parameter
+     * (see the recursive function format_array_postdata_for_curlcall)
+     * @param array $postdata
+     * @return array containing all POST parameters  (1 row = 1 POST parameter)
+     */
+    function format_postdata_for_curlcall($postdata) {
+        if (is_object($postdata)) {
+            $postdata = (array) $postdata;
+        }
+        $data = array();
+        foreach ($postdata as $k=>$v) {
+            if (is_object($v)) {
+                $v = (array) $v;
+            }
+            if (is_array($v)) {
+                $currentdata = urlencode($k);
+                $this->format_array_postdata_for_curlcall($v, $currentdata, $data);
+            }  else {
+                $data[] = urlencode($k).'='.urlencode($v);
+            }
+        }
+        $convertedpostdata = implode('&', $data);
+        return $convertedpostdata;
+    }
+
+    /**
+     * HTTP POST method
+     *
+     * @param string $url
+     * @param array|string $params
+     * @param array $options
+     * @return bool
+     */
+    public function post($url, $params = '', $options = array()){
+        $options['CURLOPT_POST']       = 1;
+        if (is_array($params)) {
+            $params = $this->format_postdata_for_curlcall($params);
+        }
+        $options['CURLOPT_POSTFIELDS'] = $params;
+        return $this->request($url, $options);
+    }
+
+    /**
+     * HTTP GET method
+     *
+     * @param string $url
+     * @param array $params
+     * @param array $options
+     * @return bool
+     */
+    public function get($url, $params = array(), $options = array()){
+        $options['CURLOPT_HTTPGET'] = 1;
+
+        if (!empty($params)){
+            $url .= (stripos($url, '?') !== false) ? '&' : '?';
+            $url .= http_build_query($params, '', '&');
+        }
+        return $this->request($url, $options);
+    }
+
+    /**
+     * HTTP PUT method
+     *
+     * @param string $url
+     * @param array $params
+     * @param array $options
+     * @return bool
+     */
+    public function put($url, $params = array(), $options = array()){
+        $file = $params['file'];
+        if (!is_file($file)){
+            return null;
+        }
+        $fp   = fopen($file, 'r');
+        $size = filesize($file);
+        $options['CURLOPT_PUT']        = 1;
+        $options['CURLOPT_INFILESIZE'] = $size;
+        $options['CURLOPT_INFILE']     = $fp;
+        if (!isset($this->options['CURLOPT_USERPWD'])){
+            $this->setopt(array('CURLOPT_USERPWD'=>'anonymous: noreply@moodle.org'));
+        }
+        $ret = $this->request($url, $options);
+        fclose($fp);
+        return $ret;
+    }
+
+    /**
+     * HTTP DELETE method
+     *
+     * @param string $url
+     * @param array $params
+     * @param array $options
+     * @return bool
+     */
+    public function delete($url, $param = array(), $options = array()){
+        $options['CURLOPT_CUSTOMREQUEST'] = 'DELETE';
+        if (!isset($options['CURLOPT_USERPWD'])) {
+            $options['CURLOPT_USERPWD'] = 'anonymous: noreply@moodle.org';
+        }
+        $ret = $this->request($url, $options);
+        return $ret;
+    }
+    /**
+     * HTTP TRACE method
+     *
+     * @param string $url
+     * @param array $options
+     * @return bool
+     */
+    public function trace($url, $options = array()){
+        $options['CURLOPT_CUSTOMREQUEST'] = 'TRACE';
+        $ret = $this->request($url, $options);
+        return $ret;
+    }
+    /**
+     * HTTP OPTIONS method
+     *
+     * @param string $url
+     * @param array $options
+     * @return bool
+     */
+    public function options($url, $options = array()){
+        $options['CURLOPT_CUSTOMREQUEST'] = 'OPTIONS';
+        $ret = $this->request($url, $options);
+        return $ret;
+    }
+    public function get_info() {
+        return $this->info;
+    }
+}
+
+/**
+ * This class is used by cURL class, use case:
+ *
+ * <code>
+ *
+ * $c = new curl(array('cache'=>true), 'module_cache'=>'repository');
+ * $ret = $c->get('http://www.google.com');
+ * </code>
+ *
+ * @package    core
+ * @subpackage file
+ * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class curl_cache {
+    /** @var string */
+    public $dir = '';
+    /**
+     *
+     * @param string @module which module is using curl_cache
+     *
+     */
+    function __construct() {
+        $this->dir = '/tmp/';
+        if (!file_exists($this->dir)) {
+            mkdir($this->dir, 0700, true);
+        }
+        $this->ttl = 1200;
+    }
+
+    /**
+     * Get cached value
+     *
+     * @param mixed $param
+     * @return bool|string
+     */
+    public function get($param){
+        $this->cleanup($this->ttl);
+        $filename = 'u_'.md5(serialize($param));
+        if(file_exists($this->dir.$filename)) {
+            $lasttime = filemtime($this->dir.$filename);
+            if(time()-$lasttime > $this->ttl)
+            {
+                return false;
+            } else {
+                $fp = fopen($this->dir.$filename, 'r');
+                $size = filesize($this->dir.$filename);
+                $content = fread($fp, $size);
+                return unserialize($content);
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Set cache value
+     *
+     * @param mixed $param
+     * @param mixed $val
+     */
+    public function set($param, $val){
+        $filename = 'u_'.md5(serialize($param));
+        $fp = fopen($this->dir.$filename, 'w');
+        fwrite($fp, serialize($val));
+        fclose($fp);
+    }
+
+    /**
+     * Remove cache files
+     *
+     * @param int $expire The number os seconds before expiry
+     */
+    public function cleanup($expire){
+        if($dir = opendir($this->dir)){
+            while (false !== ($file = readdir($dir))) {
+                if(!is_dir($file) && $file != '.' && $file != '..') {
+                    $lasttime = @filemtime($this->dir.$file);
+                    if(time() - $lasttime > $expire){
+                        @unlink($this->dir.$file);
+                    }
+                }
+            }
+        }
+    }
+    /**
+     * delete current user's cache file
+     *
+     */
+    public function refresh(){
+        if($dir = opendir($this->dir)){
+            while (false !== ($file = readdir($dir))) {
+                if(!is_dir($file) && $file != '.' && $file != '..') {
+                    if(strpos($file, 'u_')!==false){
+                        @unlink($this->dir.$file);
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/oai2client.php b/oai2client.php
new file mode 100644
index 0000000..17cd461
--- /dev/null
+++ b/oai2client.php
@@ -0,0 +1,85 @@
+<?php
+/**
+ * http://www.openarchives.org/OAI/2.0/guidelines-harvester.htm
+ * 8. Harvesting all the Metadata from a Repository
+ *
+ * Proxies, aggregators and other such agents may wish to harvest a complete copy of a repository 
+ * including set structure and all metadata formats. One strategy for doing this would be:
+ *
+ * # Issue an Identify request to find the finest datestamp granularity supported.
+ * # Issue a ListMetadataFormats request to obtain a list of all metadataPrefixes supported.
+ * # Harvest using ListRecords requests for each metadataPrefix supported. Knowledge of the
+ *   datestamp granularity allows for less overlap if granularities finer than a day are supported.
+ * # Set structure can be inferred from the setSpec elements in the header blocks of each record
+ *   returned (consistency checks are possible).
+ * # Items may be reconstructed from the constituent records. Local datestamps must be assigned to
+ *   harvested items.
+ * # Provenance and other information in <about> blocks may be re-assembled at the item level if it
+ *   is the same for all metadata formats harvested. However, this information may be supplied
+ *   differently for different metadata formats and may thus need to be store separately for each
+ *   metadata format.
+ */
+
+class OAI2Client {
+
+    public function __construct($server_base_url) {
+        $this->server_base_url = $server_base_url;
+        require_once('./curl.php');
+        $this->curl = new Curl();
+    }
+
+    public function Identify() {
+        return $this->curl->get($this->server_base_url.'?verb=Identify');
+    }
+
+    public function ListMetadataFormats($identifier = '') {
+        $url = $this->server_base_url.'?verb=ListMetadataFormats';
+        if (!empty($identifier)) {
+            $url .= "&identifier={$identifier}";
+        }
+        return $this->curl->get($url);
+    }
+
+    public function ListSets($resumptionToken = '') {
+        $url = $this->server_base_url.'?verb=ListSets';
+        return $this->curl->get($url);
+    }
+
+    public function ListIdentifiers($options = array()) {
+
+        $options_default = array('from' => null,
+                                 'until' => null,
+                                 'set' => null,
+                                 'resumptionToken' => null,
+                                 'metadataPrefix' => null); // required
+
+        $url = $this->server_base_url.'?verb=ListIdentifiers';
+
+        if (!empty($options['metadataPrefix'])) {
+            $url .= "&metadataPrefix={$options['metadataPrefix']}";
+        }
+        return $this->curl->get($url);
+    }
+
+    public function ListRecords($options = array()) {
+
+        $options_default = array('from' => null,
+                                 'until' => null,
+                                 'set' => null,
+                                 'resumptionToken' => null,
+                                 'metadataPrefix' => null); // required
+
+        $url = $this->server_base_url.'?verb=ListRecords';
+
+        if (!empty($options['metadataPrefix'])) {
+            $url .= "&metadataPrefix={$options['metadataPrefix']}";
+        }
+        return $this->curl->get($url);
+    }
+
+    public function GetRecord($identifier, $metadataPrefix) {
+        $url = $this->server_base_url.'?verb=ListRecords';
+        $url .= "&identifier={$identifier}&metadataPrefix={$metadataPrefix}";
+        return $this->curl->get($url);
+    }
+}