Implementation of REST API for Hypertable

reference: http://www.9lessons.info/2012/05/create-restful-services-api-in-php.html



192.168.122.11     192.168.122.10
+------------+     +-------------+
|master01    |     |smaster      |
|            |     |             |
|            |     |             |-+
|            |     |             | |
+------+-----+     +-------+-----+ |          +----NAT(@KVM)
       |                   |      NFS:        |
-------+-------------------+------------------+
       |                   |          
+------+-----+     +-------+-----+   
|knode020    |     |knode021     |   
|php & httpd |     |php & httpd  |   
|            |     |             |   
|            |     |             |   
+------------+     +-------------+   
192.168.122.20     192.168.122.21    

1. CDH4 installation 

   skipped

2. Hypertable 0.9.6.4 installlation

   skipped
   the binary package for cdh4 : https://groups.google.com/forum/?fromgroups=#!msg/hypertable-user/dmQhx_i7HfQ/YE32E9Omv3EJ

3. php and httpd preparation

      [root@knode020 rest]# yum install php mysql mysql-server php-mysql httpd
      ** mysql* is used for trace and debug, php and httpd is just work for REST API for HT

      [root@knode020 rest]#  chkconfig httpd on
      [root@knode020 rest]#  service httpd start

4. REST API php code for Hyptertable


    the most important source in api-ht.php as follow:

 class API extends REST {

  public $data = "";
  
  const DB_SERVER = "localhost";
  const DB = "sys";
  
  private $db = NULL;
  private $ns = NULL;

  public function __construct(){
   parent::__construct();
   $this->dbConnect(); 
  }
  public function __destruct(){
   if($this->ns)
    $this->db->namespace_close($this->ns);
  }
  
  private function dbConnect(){
   $this->db = new Hypertable_ThriftClient(self::DB_SERVER, 38080);
   if($this->db)
    $this->ns = $this->db->namespace_open(self::DB);

  }
  
  public function processApi(){
   $func = strtolower(trim(str_replace("/","",$_REQUEST['rquest'])));
   if((int)method_exists($this,$func) > 0)
    $this->$func();
   else
    $this->response('',404);    
  }
  
  
  
  private function scanner(){ 
   if($this->get_request_method() != "GET"){
    $this->response('',406);
   }
   $scanner = $this->db->scanner_open($this->ns, "RS_METRICS", new Hypertable_ThriftGen_ScanSpec(array('rot_limit' => 1000)));

   $cells = $this->db->scanner_get_cells_as_arrays($scanner);
   if(empty($cells)){
    $this->response('', 204); // If no records "No Content" status
   }

   $reault = array();
   foreach($cells as $cell)
   {
    print_r(json_encode($cell));
    $result[] = $cell;
   }
   $this->response($this->json($result), 200);
  }

  private function hql(){ 
   if($this->get_request_method() != "GET"){
    $this->response('',406);
   }
   $limit = $this->_request['limit'];  
   if($limit > 0)
    $cells = $this->db->hql_query_as_arrays($this->ns, "select * from RS_METRICS limit $limit");
   else
    $cells = $this->db->hql_query_as_arrays($this->ns, "select * from RS_METRICS ");
   if(empty($cells->cells)){
    $this->response('', 204); // If no records "No Content" status
   }

   $reault = array();
   foreach($cells->cells as $cell)
   {
    $result[] = $cell;
   }
   $this->response($this->json($result), 200);
  }

  private function json($data){   if(is_array($data)){
    return json_encode($data);
   }
  }
 }

5. test by curl

      [root@knode020 rest]#  curl -i "http://localhost/rest/api-ht.php?rquest=hql&limit=2"
      [root@knode020 rest]#  curl -i http://localhost/rest/api-ht.php?rquest=hql
      [root@knode020 rest]#  curl -i http://localhost/rest/api-ht.php?rquest=scanner

Appendix A: mysql REST API

Query User
[root@knode020 rest]# curl -i "http://localhost/rest/api.php?rquest=users"
HTTP/1.1 200 OK
Date: Wed, 23 Jan 2013 01:44:31 GMT
Server: Apache/2.2.15 (CentOS)
X-Powered-By: PHP/5.3.3
Content-Length: 166
Connection: close
Content-Type: application/json

[{"user_id":"1","user_fullname":"Sean","user_email":"seanlo0805@gmail.com"},{"user_id":"2","user_fullname":"Jewel","user_email":"testjewel@yahoo.com.tw"}]

Login User
[root@knode020 rest]# curl -i -X POST -d "email=seanlo0805@gmail.com" -d "pwd=sean" http://localhost/rest/api.php?rquest=login
HTTP/1.1 200 OK
Date: Wed, 23 Jan 2013 03:37:05 GMT
Server: Apache/2.2.15 (CentOS)
X-Powered-By: PHP/5.3.3
Content-Length: 83
Connection: close
Content-Type: application/json

{"user_id":"1","user_fullname":"Sean","user_email":"seanlo0805@gmail.com"}

Delete User
root@knode020 rest]# curl -i -X DELETE "http://localhost/rest/api.php?rquest=deleteUser&id=1"
HTTP/1.1 200 OK
Date: Wed, 23 Jan 2013 05:40:34 GMT
Server: Apache/2.2.15 (CentOS)
X-Powered-By: PHP/5.3.3
Content-Length: 61
Connection: close
Content-Type: application/json

{"status":"Success","msg":"Successfully one record deleted."}

[root@knode020 rest]# curl -i "http://localhost/rest/api.php?rquest=users"
HTTP/1.1 200 OK
Date: Wed, 23 Jan 2013 05:41:14 GMT
Server: Apache/2.2.15 (CentOS)
X-Powered-By: PHP/5.3.3
Content-Length: 82
Connection: close
Content-Type: application/json

[{"user_id":"2","user_fullname":"Jewel","user_email":"testjewel@yahoo.com.tw"}]

Appendix B: trace and debug REST API for hadoop

[QUERY]
curl -i "http://master01:50070/webhdfs/v1/hypertable?op=LISTSTATUS"


curl -i "http://master01:50070/webhdfs/v1/hypertable?op=GETFILESTATUS"

curl -i "http://master01:50070/webhdfs/v1/hypertable?op=GETHOMEDIRECTORY"

[CREATE FILE]
curl -i -X PUT "http://master01:50070/webhdfs/v1/hypertable/abc.txt?op=CREATE&user.name=root"
curl -i -X PUT "http://knode020:50075/webhdfs/v1/hypertable/abc.txt?op=CREATE&namenoderpcaddress=master01:9000&user.name=root"

[OPEN FILE]
curl -i -L "http://knode020:50075/webhdfs/v1/hypertable/abc.txt?op=OPEN&user.name=root&namenoderpcaddress=master01:9000"
curl -i -L "http://master01:50070/webhdfs/v1/hypertable/abc.txt?op=OPEN"

Appendix C: json 2 xml

<?php
function array_to_xml(array $arr, SimpleXMLElement $xml)
{
    foreach ($arr as $k => $v) {
        is_array($v)
            ? array_to_xml($v, $xml->addChild($k))
            : $xml->addChild($k, $v);
    }
    return $xml;
}

if (!isset($GLOBALS['THRIFT_ROOT']))
        $GLOBALS['THRIFT_ROOT'] = "/opt/hypertable/current/lib/php";


require_once $GLOBALS['THRIFT_ROOT'].'/ThriftClient.php';

$client = new Hypertable_ThriftClient("localhost", 38080);
$namespace = $client->namespace_open("sys");

//array('revs'=> 1);

$scanner = $client->scanner_open($namespace, "RS_METRICS", new
Hypertable_ThriftGen_ScanSpec(array('rot_limit' => 1000)));

$cells = $client->scanner_get_cells_as_arrays($scanner);

@header("Content-Type: text/xml");
$result=array();
foreach($cells as $cell)
{

        $result[] = $cell;
}
print array_to_xml($result, new SimpleXMLElement('<root/>'))->asXML();

$client->namespace_close($namespace);
?>