/branches/v2.1.0/library/Microsoft/WindowsAzure/Storage/Table.php

<?php

/**

 * Copyright (c) 2009 - 2010, RealDolmen

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *     * Redistributions of source code must retain the above copyright

 *       notice, this list of conditions and the following disclaimer.

 *     * Redistributions in binary form must reproduce the above copyright

 *       notice, this list of conditions and the following disclaimer in the

 *       documentation and/or other materials provided with the distribution.

 *     * Neither the name of RealDolmen nor the

 *       names of its contributors may be used to endorse or promote products

 *       derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY RealDolmen ''AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 * DISCLAIMED. IN NO EVENT SHALL RealDolmen BE LIABLE FOR ANY

 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * @category   Microsoft

 * @package    Microsoft_WindowsAzure

 * @subpackage Storage

 * @copyright  Copyright (c) 2009 - 2010, RealDolmen (http://www.realdolmen.com)

 * @license    http://phpazure.codeplex.com/license

 * @version    $Id: Blob.php 14561 2009-05-07 08:05:12Z unknown $

 */



/**

 * @see Microsoft_WindowsAzure_Credentials_CredentialsAbstract

 */

require_once 'Microsoft/WindowsAzure/Credentials/CredentialsAbstract.php';



/**

 * @see Microsoft_WindowsAzure_Credentials_SharedKey

 */

require_once 'Microsoft/WindowsAzure/Credentials/SharedKey.php';



/**

 * @see Microsoft_WindowsAzure_Credentials_SharedKeyLite

 */

require_once 'Microsoft/WindowsAzure/Credentials/SharedKeyLite.php';



/**

 * @see Microsoft_WindowsAzure_RetryPolicy_RetryPolicyAbstract

 */

require_once 'Microsoft/WindowsAzure/RetryPolicy/RetryPolicyAbstract.php';



/**

 * @see Microsoft_Http_Client

 */

require_once 'Microsoft/Http/Client.php';



/**

 * @see Microsoft_Http_Response

 */

require_once 'Microsoft/Http/Response.php';



/**

 * @see Microsoft_WindowsAzure_Storage

 */

require_once 'Microsoft/WindowsAzure/Storage.php';



/**

 * @see Microsoft_WindowsAzure_Storage_BatchStorageAbstract

 */

require_once 'Microsoft/WindowsAzure/Storage/BatchStorageAbstract.php';



/**

 * @see Microsoft_WindowsAzure_Storage_TableInstance

 */

require_once 'Microsoft/WindowsAzure/Storage/TableInstance.php';



/**

 * @see Microsoft_WindowsAzure_Storage_TableEntity

 */

require_once 'Microsoft/WindowsAzure/Storage/TableEntity.php';



/**

 * @see Microsoft_WindowsAzure_Storage_DynamicTableEntity

 */

require_once 'Microsoft/WindowsAzure/Storage/DynamicTableEntity.php';



/**

 * @see Microsoft_WindowsAzure_Storage_TableEntityQuery

 */

require_once 'Microsoft/WindowsAzure/Storage/TableEntityQuery.php';



/**

 * @see Microsoft_WindowsAzure_Exception

 */

require_once 'Microsoft/WindowsAzure/Exception.php';





/**

 * @category   Microsoft

 * @package    Microsoft_WindowsAzure

 * @subpackage Storage

 * @copyright  Copyright (c) 2009 - 2010, RealDolmen (http://www.realdolmen.com)

 * @license    http://phpazure.codeplex.com/license

 */

class Microsoft_WindowsAzure_Storage_Table

    extends Microsoft_WindowsAzure_Storage_BatchStorageAbstract

{

	/**

	 * Throw Microsoft_WindowsAzure_Exception when a property is not specified in Windows Azure?

	 * Defaults to true, making behaviour similar to Windows Azure StorageClient in .NET.

	 * 

	 * @var boolean

	 */

	protected $_throwExceptionOnMissingData = true;

	

	/**

	 * Throw Microsoft_WindowsAzure_Exception when a property is not specified in Windows Azure?

	 * Defaults to true, making behaviour similar to Windows Azure StorageClient in .NET.

	 * 

	 * @param boolean $value

	 */

	public function setThrowExceptionOnMissingData($value = true)

	{

		$this->_throwExceptionOnMissingData = $value;

	}

	

	/**

	 * Throw Microsoft_WindowsAzure_Exception when a property is not specified in Windows Azure?

	 */

	public function getThrowExceptionOnMissingData()

	{

		return $this->_throwExceptionOnMissingData;

	}

	

	/**

	 * Creates a new Microsoft_WindowsAzure_Storage_Table instance

	 *

	 * @param string $host Storage host name

	 * @param string $accountName Account name for Windows Azure

	 * @param string $accountKey Account key for Windows Azure

	 * @param boolean $usePathStyleUri Use path-style URI's

	 * @param Microsoft_WindowsAzure_RetryPolicy_RetryPolicyAbstract $retryPolicy Retry policy to use when making requests

	 */

	public function __construct($host = Microsoft_WindowsAzure_Storage::URL_DEV_TABLE, $accountName = Microsoft_WindowsAzure_Credentials_CredentialsAbstract::DEVSTORE_ACCOUNT, $accountKey = Microsoft_WindowsAzure_Credentials_CredentialsAbstract::DEVSTORE_KEY, $usePathStyleUri = false, Microsoft_WindowsAzure_RetryPolicy_RetryPolicyAbstract $retryPolicy = null)

	{

		parent::__construct($host, $accountName, $accountKey, $usePathStyleUri, $retryPolicy);



	    // Always use SharedKeyLite authentication

	    $this->_credentials = new Microsoft_WindowsAzure_Credentials_SharedKeyLite($accountName, $accountKey, $this->_usePathStyleUri);

	    

	    // API version

		$this->_apiVersion = '2009-09-19';

	}

	

	/**

	 * Check if a table exists

	 * 

	 * @param string $tableName Table name

	 * @return boolean

	 */

	public function tableExists($tableName = '')

	{

		if ($tableName === '') {

			throw new Microsoft_WindowsAzure_Exception('Table name is not specified.');

		}

			

		// List tables

        $tables = $this->listTables(); // 2009-09-19 does not support $this->listTables($tableName); all of a sudden...

        foreach ($tables as $table) {

            if ($table->Name == $tableName) {

                return true;

            }

        }

        

        return false;

	}

	

	/**

	 * List tables

	 *

	 * @param  string $nextTableName Next table name, used for listing tables when total amount of tables is > 1000.

	 * @return array

	 * @throws Microsoft_WindowsAzure_Exception

	 */

	public function listTables($nextTableName = '')

	{

	    // Build query string

		$queryString = array();

	    if ($nextTableName != '') {

	        $queryString[] = 'NextTableName=' . $nextTableName;

	    }

	    $queryString = self::createQueryStringFromArray($queryString);

	    

		// Perform request

		$response = $this->_performRequest('Tables', $queryString, Microsoft_Http_Client::GET, null, true);

		if ($response->isSuccessful()) {	    

		    // Parse result

		    $result = $this->_parseResponse($response);	

		    

		    if (!$result || !$result->entry) {

		        return array();

		    }

	        

		    $entries = null;

		    if (count($result->entry) > 1) {

		        $entries = $result->entry;

		    } else {

		        $entries = array($result->entry);

		    }



		    // Create return value

		    $returnValue = array();		    

		    foreach ($entries as $entry) {

		        $tableName = $entry->xpath('.//m:properties/d:TableName');

		        $tableName = (string)$tableName[0];

		        

		        $returnValue[] = new Microsoft_WindowsAzure_Storage_TableInstance(

		            (string)$entry->id,

		            $tableName,

		            (string)$entry->link['href'],

		            (string)$entry->updated

		        );

		    }

		    

			// More tables?

		    if (!is_null($response->getHeader('x-ms-continuation-NextTableName'))) {

		        $returnValue = array_merge($returnValue, $this->listTables($response->getHeader('x-ms-continuation-NextTableName')));

		    }



		    return $returnValue;

		} else {

			throw new Microsoft_WindowsAzure_Exception($this->_getErrorMessage($response, 'Resource could not be accessed.'));

		}

	}

	

	/**

	 * Create table

	 *

	 * @param string $tableName Table name

	 * @return Microsoft_WindowsAzure_Storage_TableInstance

	 * @throws Microsoft_WindowsAzure_Exception

	 */

	public function createTable($tableName = '')

	{

		if ($tableName === '') {

			throw new Microsoft_WindowsAzure_Exception('Table name is not specified.');

		}

			

		// Generate request body

		$requestBody = '<?xml version="1.0" encoding="utf-8" standalone="yes"?>

                        <entry

                        	xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices"

                        	xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata"

                        	xmlns="http://www.w3.org/2005/Atom">

                          <title />

                          <updated>{tpl:Updated}</updated>

                          <author>

                            <name />

                          </author>

                          <id />

                          <content type="application/xml">

                            <m:properties>

                              <d:TableName>{tpl:TableName}</d:TableName>

                            </m:properties>

                          </content>

                        </entry>';

		

        $requestBody = $this->_fillTemplate($requestBody, array(

            'BaseUrl' => $this->getBaseUrl(),

            'TableName' => htmlspecialchars($tableName),

        	'Updated' => $this->isoDate(),

            'AccountName' => $this->_accountName

        ));

        

        // Add header information

        $headers = array();

        $headers['Content-Type'] = 'application/atom+xml';

        $headers['DataServiceVersion'] = '1.0;NetFx';

        $headers['MaxDataServiceVersion'] = '1.0;NetFx';        



		// Perform request

		$response = $this->_performRequest('Tables', '', Microsoft_Http_Client::POST, $headers, true, $requestBody);

		if ($response->isSuccessful()) {

		    // Parse response

		    $entry = $this->_parseResponse($response);

		    

		    $tableName = $entry->xpath('.//m:properties/d:TableName');

		    $tableName = (string)$tableName[0];

		        

		    return new Microsoft_WindowsAzure_Storage_TableInstance(

		        (string)$entry->id,

		        $tableName,

		        (string)$entry->link['href'],

		        (string)$entry->updated

		    );

		} else {

			throw new Microsoft_WindowsAzure_Exception($this->_getErrorMessage($response, 'Resource could not be accessed.'));

		}

	}

	

	/**

	 * Create table if it does not exist

	 *

	 * @param string $tableName Table name

	 * @throws Microsoft_WindowsAzure_Exception

	 */

	public function createTableIfNotExists($tableName = '')

	{

		if (!$this->tableExists($tableName)) {

			$this->createTable($tableName);

		}

	}

	

	/**

	 * Delete table

	 *

	 * @param string $tableName Table name

	 * @throws Microsoft_WindowsAzure_Exception

	 */

	public function deleteTable($tableName = '')

	{

		if ($tableName === '') {

			throw new Microsoft_WindowsAzure_Exception('Table name is not specified.');

		}



        // Add header information

        $headers = array();

        $headers['Content-Type'] = 'application/atom+xml';



		// Perform request

		$response = $this->_performRequest('Tables(\'' . $tableName . '\')', '', Microsoft_Http_Client::DELETE, $headers, true, null);

		if (!$response->isSuccessful()) {

			throw new Microsoft_WindowsAzure_Exception($this->_getErrorMessage($response, 'Resource could not be accessed.'));

		}

	}

	

	/**

	 * Insert entity into table

	 * 

	 * @param string                              $tableName   Table name

	 * @param Microsoft_WindowsAzure_Storage_TableEntity $entity      Entity to insert

	 * @return Microsoft_WindowsAzure_Storage_TableEntity

	 * @throws Microsoft_WindowsAzure_Exception

	 */

	public function insertEntity($tableName = '', Microsoft_WindowsAzure_Storage_TableEntity $entity = null)

	{

		if ($tableName === '') {

			throw new Microsoft_WindowsAzure_Exception('Table name is not specified.');

		}

		if (is_null($entity)) {

			throw new Microsoft_WindowsAzure_Exception('Entity is not specified.');

		}

		                     

		// Generate request body

		$requestBody = '<?xml version="1.0" encoding="utf-8" standalone="yes"?>

                        <entry xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns="http://www.w3.org/2005/Atom">

                          <title />

                          <updated>{tpl:Updated}</updated>

                          <author>

                            <name />

                          </author>

                          <id />

                          <content type="application/xml">

                            <m:properties>

                              {tpl:Properties}

                            </m:properties>

                          </content>

                        </entry>';

		

        $requestBody = $this->_fillTemplate($requestBody, array(

        	'Updated'    => $this->isoDate(),

            'Properties' => $this->_generateAzureRepresentation($entity)

        ));



        // Add header information

        $headers = array();

        $headers['Content-Type'] = 'application/atom+xml';



		// Perform request

	    $response = null;

	    if ($this->isInBatch()) {

		    $this->getCurrentBatch()->enlistOperation($tableName, '', Microsoft_Http_Client::POST, $headers, true, $requestBody);

		    return null;

		} else {

		    $response = $this->_performRequest($tableName, '', Microsoft_Http_Client::POST, $headers, true, $requestBody);

		}

		if ($response->isSuccessful()) {

		    // Parse result

		    $result = $this->_parseResponse($response);

		    

		    $timestamp = $result->xpath('//m:properties/d:Timestamp');

		    $timestamp = (string)$timestamp[0];



		    $etag      = $result->attributes('http://schemas.microsoft.com/ado/2007/08/dataservices/metadata');

		    $etag      = (string)$etag['etag'];

		    

		    // Update properties

		    $entity->setTimestamp($timestamp);

		    $entity->setEtag($etag);



		    return $entity;

		} else {

			throw new Microsoft_WindowsAzure_Exception($this->_getErrorMessage($response, 'Resource could not be accessed.'));

		}

	}

	

	/**

	 * Delete entity from table

	 * 

	 * @param string                              $tableName   Table name

	 * @param Microsoft_WindowsAzure_Storage_TableEntity $entity      Entity to delete

	 * @param boolean                             $verifyEtag  Verify etag of the entity (used for concurrency)

	 * @throws Microsoft_WindowsAzure_Exception

	 */

	public function deleteEntity($tableName = '', Microsoft_WindowsAzure_Storage_TableEntity $entity = null, $verifyEtag = false)

	{

		if ($tableName === '') {

			throw new Microsoft_WindowsAzure_Exception('Table name is not specified.');

		}

		if (is_null($entity)) {

			throw new Microsoft_WindowsAzure_Exception('Entity is not specified.');

		}

		                     

        // Add header information

        $headers = array();

        if (!$this->isInBatch()) {

        	// http://social.msdn.microsoft.com/Forums/en-US/windowsazure/thread/9e255447-4dc7-458a-99d3-bdc04bdc5474/

            $headers['Content-Type']   = 'application/atom+xml';

        }

        $headers['Content-Length'] = 0;

        if (!$verifyEtag) {

            $headers['If-Match']       = '*';

        } else {

            $headers['If-Match']       = $entity->getEtag();

        }



		// Perform request

	    $response = null;

	    if ($this->isInBatch()) {

		    $this->getCurrentBatch()->enlistOperation($tableName . '(PartitionKey=\'' . $entity->getPartitionKey() . '\', RowKey=\'' . $entity->getRowKey() . '\')', '', Microsoft_Http_Client::DELETE, $headers, true, null);

		    return null;

		} else {

		    $response = $this->_performRequest($tableName . '(PartitionKey=\'' . $entity->getPartitionKey() . '\', RowKey=\'' . $entity->getRowKey() . '\')', '', Microsoft_Http_Client::DELETE, $headers, true, null);

		}

		if (!$response->isSuccessful()) {

		    throw new Microsoft_WindowsAzure_Exception($this->_getErrorMessage($response, 'Resource could not be accessed.'));

		}

	}

	

	/**

	 * Retrieve entity from table, by id

	 * 

	 * @param string $tableName    Table name

	 * @param string $partitionKey Partition key

	 * @param string $rowKey       Row key

	 * @param string $entityClass  Entity class name* 

	 * @return Microsoft_WindowsAzure_Storage_TableEntity

	 * @throws Microsoft_WindowsAzure_Exception

	 */

	public function retrieveEntityById($tableName = '', $partitionKey = '', $rowKey = '', $entityClass = 'Microsoft_WindowsAzure_Storage_DynamicTableEntity')

	{

		if ($tableName === '') {

			throw new Microsoft_WindowsAzure_Exception('Table name is not specified.');

		}

		if ($partitionKey === '') {

			throw new Microsoft_WindowsAzure_Exception('Partition key is not specified.');

		}

		if ($rowKey === '') {

			throw new Microsoft_WindowsAzure_Exception('Row key is not specified.');

		}

		if ($entityClass === '') {

			throw new Microsoft_WindowsAzure_Exception('Entity class is not specified.');

		}



			

		// Check for combined size of partition key and row key

		// http://msdn.microsoft.com/en-us/library/dd179421.aspx

		if (strlen($partitionKey . $rowKey) >= 256) {

		    // Start a batch if possible

		    if ($this->isInBatch()) {

		        throw new Microsoft_WindowsAzure_Exception('Entity cannot be retrieved. A transaction is required to retrieve the entity, but another transaction is already active.');

		    }

		        

		    $this->startBatch();

		}

		

		// Fetch entities from Azure

        $result = $this->retrieveEntities(

            $this->select()

                 ->from($tableName)

                 ->wherePartitionKey($partitionKey)

                 ->whereRowKey($rowKey),

            '',

            $entityClass

        );

        

        // Return

        if (count($result) == 1) {

            return $result[0];

        }

        

        return null;

	}

	

	/**

	 * Create a new Microsoft_WindowsAzure_Storage_TableEntityQuery

	 * 

	 * @return Microsoft_WindowsAzure_Storage_TableEntityQuery

	 */

	public function select()

	{

	    return new Microsoft_WindowsAzure_Storage_TableEntityQuery();

	}

	

	/**

	 * Retrieve entities from table

	 * 

	 * @param string $tableName|Microsoft_WindowsAzure_Storage_TableEntityQuery    Table name -or- Microsoft_WindowsAzure_Storage_TableEntityQuery instance

	 * @param string $filter                                                Filter condition (not applied when $tableName is a Microsoft_WindowsAzure_Storage_TableEntityQuery instance)

	 * @param string $entityClass                                           Entity class name

	 * @param string $nextPartitionKey                                      Next partition key, used for listing entities when total amount of entities is > 1000.

	 * @param string $nextRowKey                                            Next row key, used for listing entities when total amount of entities is > 1000.

	 * @return array Array of Microsoft_WindowsAzure_Storage_TableEntity

	 * @throws Microsoft_WindowsAzure_Exception

	 */

	public function retrieveEntities($tableName = '', $filter = '', $entityClass = 'Microsoft_WindowsAzure_Storage_DynamicTableEntity', $nextPartitionKey = null, $nextRowKey = null)

	{

		if ($tableName === '') {

			throw new Microsoft_WindowsAzure_Exception('Table name is not specified.');

		}

		if ($entityClass === '') {

			throw new Microsoft_WindowsAzure_Exception('Entity class is not specified.');

		}



		// Convenience...

		if (class_exists($filter)) {

		    $entityClass = $filter;

		    $filter = '';

		}

			

		// Query string

		$queryString = '';



		// Determine query

		if (is_string($tableName)) {

		    // Option 1: $tableName is a string

		    

		    // Append parentheses

		    $tableName .= '()';

		    

    	    // Build query

    	    $query = array();

    	    

    		// Filter?

    		if ($filter !== '') {

    		    $query[] = '$filter=' . Microsoft_WindowsAzure_Storage_TableEntityQuery::encodeQuery($filter);

    		}

    		    

    	    // Build queryString

    	    if (count($query) > 0)  {

    	        $queryString = '?' . implode('&', $query);

    	    }

		} else if (get_class($tableName) == 'Microsoft_WindowsAzure_Storage_TableEntityQuery') {

		    // Option 2: $tableName is a Microsoft_WindowsAzure_Storage_TableEntityQuery instance



		    // Build queryString

		    $queryString = $tableName->assembleQueryString(true);



		    // Change $tableName

		    $tableName = $tableName->assembleFrom(true);

		} else {

		    throw new Microsoft_WindowsAzure_Exception('Invalid argument: $tableName');

		}

		

		// Add continuation querystring parameters?

		if (!is_null($nextPartitionKey) && !is_null($nextRowKey)) {

		    if ($queryString !== '') {

		        $queryString .= '&';

		    }

		        

		    $queryString .= '&NextPartitionKey=' . rawurlencode($nextPartitionKey) . '&NextRowKey=' . rawurlencode($nextRowKey);

		}



		// Perform request

	    $response = null;

	    if ($this->isInBatch() && $this->getCurrentBatch()->getOperationCount() == 0) {

		    $this->getCurrentBatch()->enlistOperation($tableName, $queryString, Microsoft_Http_Client::GET, array(), true, null);

		    $response = $this->getCurrentBatch()->commit();

		    

		    // Get inner response (multipart)

		    $innerResponse = $response->getBody();

		    $innerResponse = substr($innerResponse, strpos($innerResponse, 'HTTP/1.1 200 OK'));

		    $innerResponse = substr($innerResponse, 0, strpos($innerResponse, '--batchresponse'));

		    $response = Microsoft_Http_Response::fromString($innerResponse);

		} else {

		    $response = $this->_performRequest($tableName, $queryString, Microsoft_Http_Client::GET, array(), true, null);

		}



		if ($response->isSuccessful()) {

		    // Parse result

		    $result = $this->_parseResponse($response);

		    if (!$result) {

		        return array();

		    }



		    $entries = null;

		    if ($result->entry) {

    		    if (count($result->entry) > 1) {

    		        $entries = $result->entry;

    		    } else {

    		        $entries = array($result->entry);

    		    }

		    } else {

		        // This one is tricky... If we have properties defined, we have an entity.

		        $properties = $result->xpath('//m:properties');

		        if ($properties) {

		            $entries = array($result);

		        } else {

		            return array();

		        }

		    }



		    // Create return value

		    $returnValue = array();		    

		    foreach ($entries as $entry) {

    		    // Parse properties

    		    $properties = $entry->xpath('.//m:properties');

    		    $properties = $properties[0]->children('http://schemas.microsoft.com/ado/2007/08/dataservices');

    		    

    		    // Create entity

    		    $entity = new $entityClass('', '');

    		    $entity->setAzureValues((array)$properties, $this->_throwExceptionOnMissingData);

    		    

    		    // If we have a Microsoft_WindowsAzure_Storage_DynamicTableEntity, make sure all property types are OK

    		    if ($entity instanceof Microsoft_WindowsAzure_Storage_DynamicTableEntity) {

    		        foreach ($properties as $key => $value) {  

    		            $attributes = $value->attributes('http://schemas.microsoft.com/ado/2007/08/dataservices/metadata');

    		            $type = (string)$attributes['type'];

    		            if ($type !== '') {

    		                $entity->setAzurePropertyType($key, $type);

    		            }

    		        }

    		    }

    

    		    // Update etag

    		    $etag      = $entry->attributes('http://schemas.microsoft.com/ado/2007/08/dataservices/metadata');

    		    $etag      = (string)$etag['etag'];

    		    $entity->setEtag($etag);

    		    

    		    // Add to result

    		    $returnValue[] = $entity;

		    }



			// More entities?

		    if (!is_null($response->getHeader('x-ms-continuation-NextPartitionKey')) && !is_null($response->getHeader('x-ms-continuation-NextRowKey'))) {

		        if (strpos($queryString, '$top') === false) {

		            $returnValue = array_merge($returnValue, $this->retrieveEntities($tableName, $filter, $entityClass, $response->getHeader('x-ms-continuation-NextPartitionKey'), $response->getHeader('x-ms-continuation-NextRowKey')));

		        }

		    }

		    

		    // Return

		    return $returnValue;

		} else {

		    throw new Microsoft_WindowsAzure_Exception($this->_getErrorMessage($response, 'Resource could not be accessed.'));

		}

	}

	

	/**

	 * Update entity by replacing it

	 * 

	 * @param string                              $tableName   Table name

	 * @param Microsoft_WindowsAzure_Storage_TableEntity $entity      Entity to update

	 * @param boolean                             $verifyEtag  Verify etag of the entity (used for concurrency)

	 * @throws Microsoft_WindowsAzure_Exception

	 */

	public function updateEntity($tableName = '', Microsoft_WindowsAzure_Storage_TableEntity $entity = null, $verifyEtag = false)

	{

	    return $this->_changeEntity(Microsoft_Http_Client::PUT, $tableName, $entity, $verifyEtag);

	}

	

	/**

	 * Update entity by adding or updating properties

	 * 

	 * @param string                              $tableName   Table name

	 * @param Microsoft_WindowsAzure_Storage_TableEntity $entity      Entity to update

	 * @param boolean                             $verifyEtag  Verify etag of the entity (used for concurrency)

	 * @param array                               $properties  Properties to merge. All properties will be used when omitted.

	 * @throws Microsoft_WindowsAzure_Exception

	 */

	public function mergeEntity($tableName = '', Microsoft_WindowsAzure_Storage_TableEntity $entity = null, $verifyEtag = false, $properties = array())

	{

		$mergeEntity = null;

		if (is_array($properties) && count($properties) > 0) {

			// Build a new object

			$mergeEntity = new Microsoft_WindowsAzure_Storage_DynamicTableEntity($entity->getPartitionKey(), $entity->getRowKey());

			

			// Keep only values mentioned in $properties

			$azureValues = $entity->getAzureValues();

			foreach ($azureValues as $key => $value) {

				if (in_array($value->Name, $properties)) {

					$mergeEntity->setAzureProperty($value->Name, $value->Value, $value->Type);

				}

			}

		} else {

			$mergeEntity = $entity;

		}

		

		// Ensure entity timestamp matches updated timestamp 

        $entity->setTimestamp($this->isoDate());

        

	    return $this->_changeEntity(Microsoft_Http_Client::MERGE, $tableName, $mergeEntity, $verifyEtag);

	}

	

	/**

	 * Get error message from Microsoft_Http_Response

	 * 

	 * @param Microsoft_Http_Response $response Repsonse

	 * @param string $alternativeError Alternative error message

	 * @return string

	 */

	protected function _getErrorMessage(Microsoft_Http_Response $response, $alternativeError = 'Unknown error.')

	{

		$response = $this->_parseResponse($response);

		if ($response && $response->message) {

		    return (string)$response->message;

		} else {

		    return $alternativeError;

		}

	}

	

	/**

	 * Update entity / merge entity

	 * 

	 * @param string                              $httpVerb    HTTP verb to use (PUT = update, MERGE = merge)

	 * @param string                              $tableName   Table name

	 * @param Microsoft_WindowsAzure_Storage_TableEntity $entity      Entity to update

	 * @param boolean                             $verifyEtag  Verify etag of the entity (used for concurrency)

	 * @throws Microsoft_WindowsAzure_Exception

	 */

	protected function _changeEntity($httpVerb = Microsoft_Http_Client::PUT, $tableName = '', Microsoft_WindowsAzure_Storage_TableEntity $entity = null, $verifyEtag = false)

	{

		if ($tableName === '') {

			throw new Microsoft_WindowsAzure_Exception('Table name is not specified.');

		}

		if (is_null($entity)) {

			throw new Microsoft_WindowsAzure_Exception('Entity is not specified.');

		}

		                     

        // Add header information

        $headers = array();

        $headers['Content-Type']   = 'application/atom+xml';

        $headers['Content-Length'] = 0;

        if (!$verifyEtag) {

            $headers['If-Match']       = '*';

        } else {

            $headers['If-Match']       = $entity->getEtag();

        }



	    // Generate request body

		$requestBody = '<?xml version="1.0" encoding="utf-8" standalone="yes"?>

                        <entry xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns="http://www.w3.org/2005/Atom">

                          <title />

                          <updated>{tpl:Updated}</updated>

                          <author>

                            <name />

                          </author>

                          <id />

                          <content type="application/xml">

                            <m:properties>

                              {tpl:Properties}

                            </m:properties>

                          </content>

                        </entry>';

		

		// Attempt to get timestamp from entity

        $timestamp = $entity->getTimestamp();

        if ($timestamp == Microsoft_WindowsAzure_Storage_TableEntity::DEFAULT_TIMESTAMP) {

            $timestamp = $this->isoDate();

        }

        

        $requestBody = $this->_fillTemplate($requestBody, array(

        	'Updated'    => $timestamp,

            'Properties' => $this->_generateAzureRepresentation($entity)

        ));



        // Add header information

        $headers = array();

        $headers['Content-Type'] = 'application/atom+xml';

	    if (!$verifyEtag) {

            $headers['If-Match']       = '*';

        } else {

            $headers['If-Match']       = $entity->getEtag();

        }

        

		// Perform request

		$response = null;

	    if ($this->isInBatch()) {

		    $this->getCurrentBatch()->enlistOperation($tableName . '(PartitionKey=\'' . $entity->getPartitionKey() . '\', RowKey=\'' . $entity->getRowKey() . '\')', '', $httpVerb, $headers, true, $requestBody);

		    return null;

		} else {

		    $response = $this->_performRequest($tableName . '(PartitionKey=\'' . $entity->getPartitionKey() . '\', RowKey=\'' . $entity->getRowKey() . '\')', '', $httpVerb, $headers, true, $requestBody);

		}

		if ($response->isSuccessful()) {

		    // Update properties

			$entity->setEtag($response->getHeader('Etag'));

			$entity->setTimestamp($response->getHeader('Last-modified'));



		    return $entity;

		} else {

			throw new Microsoft_WindowsAzure_Exception($this->_getErrorMessage($response, 'Resource could not be accessed.'));

		}

	}

	

	/**

	 * Generate RFC 1123 compliant date string

	 * 

	 * @return string

	 */

	protected function _rfcDate()

	{

	    return gmdate('D, d M Y H:i:s', time()) . ' GMT'; // RFC 1123

	}

	

	/**

	 * Fill text template with variables from key/value array

	 * 

	 * @param string $templateText Template text

	 * @param array $variables Array containing key/value pairs

	 * @return string

	 */

	protected function _fillTemplate($templateText, $variables = array())

	{

	    foreach ($variables as $key => $value) {

	        $templateText = str_replace('{tpl:' . $key . '}', $value, $templateText);

	    }

	    return $templateText;

	}

	

	/**

	 * Generate Azure representation from entity (creates atompub markup from properties)

	 * 

	 * @param Microsoft_WindowsAzure_Storage_TableEntity $entity

	 * @return string

	 */

	protected function _generateAzureRepresentation(Microsoft_WindowsAzure_Storage_TableEntity $entity = null)

	{

		// Generate Azure representation from entity

		$azureRepresentation = array();

		$azureValues         = $entity->getAzureValues();

		foreach ($azureValues as $azureValue) {

		    $value = array();

		    $value[] = '<d:' . $azureValue->Name;

		    if ($azureValue->Type != '') {

		        $value[] = ' m:type="' . $azureValue->Type . '"';

		    }

		    if (is_null($azureValue->Value)) {

		        $value[] = ' m:null="true"'; 

		    }

		    $value[] = '>';

		    

		    if (!is_null($azureValue->Value)) {

		        if (strtolower($azureValue->Type) == 'edm.boolean') {

		            $value[] = ($azureValue->Value == true ? '1' : '0');

		        } else {

		            $value[] = htmlspecialchars($azureValue->Value);

		        }

		    }

		    

		    $value[] = '</d:' . $azureValue->Name . '>';

		    $azureRepresentation[] = implode('', $value);

		}



		return implode('', $azureRepresentation);

	}

	

		/**

	 * Perform request using Microsoft_Http_Client channel

	 *

	 * @param string $path Path

	 * @param string $queryString Query string

	 * @param string $httpVerb HTTP verb the request will use

	 * @param array $headers x-ms headers to add

	 * @param boolean $forTableStorage Is the request for table storage?

	 * @param mixed $rawData Optional RAW HTTP data to be sent over the wire

	 * @param string $resourceType Resource type

	 * @param string $requiredPermission Required permission

	 * @return Microsoft_Http_Response

	 */

	protected function _performRequest(

		$path = '/',

		$queryString = '',

		$httpVerb = Microsoft_Http_Client::GET,

		$headers = array(),

		$forTableStorage = false,

		$rawData = null,

		$resourceType = Microsoft_WindowsAzure_Storage::RESOURCE_UNKNOWN,

		$requiredPermission = Microsoft_WindowsAzure_Credentials_CredentialsAbstract::PERMISSION_READ

	) {

		// Add headers

		$headers['DataServiceVersion'] = '1.0;NetFx';

		$headers['MaxDataServiceVersion'] = '1.0;NetFx';



		// Perform request

		return parent::_performRequest(

			$path,

			$queryString,

			$httpVerb,

			$headers,

			$forTableStorage,

			$rawData,

			$resourceType,

			$requiredPermission

		);

	}

}