org.netfrag.glib/DesignPattern/RemoteProxy.php

<?php
/**
 * This file contains the DesignPattern::RemoteProxy class
 *
 * @author Andreas Motl <andreas.motl@ilo.de>
 * @package org.netfrag.glib
 * @name DesignPattern::RemoteProxy
 * @filesource
 *
 *
 * <b>Cvs-Log:</b>
 *
 * <pre>
 * -------------------------------------------------------------------------
 *    $Id: RemoteProxy.php,v 1.6 2003/03/05 17:28:43 joko Exp $
 * -------------------------------------------------------------------------
 *    $Log: RemoteProxy.php,v $
 *    Revision 1.6  2003/03/05 17:28:43  joko
 *    updated docu (phpDocumentor testing....)
 *
 *    Revision 1.5  2003/03/05 17:02:22  joko
 *    updated docu (phpDocumentor testing....)
 *
 *    Revision 1.4  2003/03/05 16:32:19  joko
 *    updated docu (phpDocumentor testing....)
 *
 *    Revision 1.3  2003/03/05 16:10:17  joko
 *    updated docu (phpDocumentor testing....)
 *
 *    Revision 1.2  2003/03/05 12:14:02  joko
 *    renamed method
 *    constructor argument expansion
 *
 *    Revision 1.1  2003/03/03 22:06:46  joko
 *    refactored from Data::Driver::Proxy
 *
 *    Revision 1.3  2003/03/01 04:56:38  joko
 *    new comment style for large blocks - stolen from phpHtmlLib
 *    commit-log encapsulated into such a block
 *    introduced some documentation
 *    refactored todo (now also inside a stylish block)
 *
 *    Revision 1.2  2003/02/13 21:48:09  joko
 *    + caching mechanisms more configurable now
 *
 *    Revision 1.1  2003/02/09 17:23:21  joko
 *    + refactored from flib/Application/RPC/ProxyObject.php
 *
 *    Revision 1.7  2003/02/03 03:31:38  jonen
 *    - moved '$encoder->toISO()' to 'Remote.php'
 *
 *    Revision 1.6  2002/12/22 13:26:20  jonen
 *    + added support of tangram independent id (e.g. Data::UUID) toggled by option at conrtuctor
 *
 *    Revision 1.5  2002/12/18 22:36:49  jonen
 *    + added support to get remote objects via backend via 'guid'
 *    + renamed '_loadBackend' to '_loadRemote'
 *    + constructor now accepts additional options:
 *      + remote: try to get object via '_loadRemote' ...
 *      + oid: use the given identifier as an 'oid' when doing '_loadRemote'
 *      + guid: use the given identifier as a 'guid' when doing '_loadRemote'
 *
 *    Revision 1.4  2002/12/12 02:46:31  joko
 *    + state (session) gets flushed when data was successfully loaded from remote side
 *    + fixed _loadBackend
 *    + fixed flushState
 *
 *    Revision 1.3  2002/12/06 04:12:54  joko
 *    + replaced 'xyzCache' through 'xyzProxy'
 *    + function store(...)
 *
 *    Revision 1.2  2002/12/05 21:44:09  joko
 *    + debugging
 *
 *    Revision 1.1  2002/12/01 17:23:58  joko
 *    + initial check-in
 *
 *    Revision 1.11  2002/11/12 06:05:58  cvsjoko
 *    + renamed class: Text_Encode -> TextEncode
 *
 *    Revision 1.10  2002/10/29 19:15:33  cvsjoko
 *    - moved utf8/iso-conversion to lib/utils/Text_Encode.php
 *
 *    Revision 1.9  2002/10/26 12:32:36  cvsjoko
 *    - removed debugging via "print"
 *    + added generic logging via PEAR::Log
 *
 *    Revision 1.8  2002/10/22 09:51:38  cvsmax
 *    + moved semi-method 'createBackend' to method $site->user->create at User.class.php
 *
 *    Revision 1.7  2002/10/21 18:27:09  cvsjoko
 *    - manually disabled any form of caching
 *
 *    Revision 1.6  2002/10/17 03:48:47  cvsmax
 *    + new
 *       + function _createBackend      create new Backend
 *       + function _create             api-create
 *
 *    Revision 1.5  2002/10/16 03:37:54  cvsjoko
 *    + bugfix: wrong comparison in restriction to save to array
 *
 *    Revision 1.4  2002/10/10 03:04:23  cvsjoko
 *    + no debug-output
 *
 *    Revision 1.3  2002/10/10 03:03:27  cvsjoko
 *    + bugfix: save object to cache only if payload from backend isn't empty
 *
 *    Revision 1.2  2002/10/10 02:40:06  cvsjoko
 *    + new level of data-caching (session and persistant)
 *        + function _loadState loads data from session
 *        + function _saveState saves data to session
 *        + function save               api-save (session & backend)
 *        + function _commit    saves data to backend
 *    + handy utils
 *        + function _setAttributes
 *        + function flushState
 *
 *    Revision 1.1  2002/10/09 00:51:39  cvsjoko
 *    + new
 * -------------------------------------------------------------------------
 * </pre>
 *
 */


/**
 * Load required modules:
 *
 */
loadModule('DesignPattern::Proxy');


/**
 * DesignPattern::RemoteProxy  --  Multiple stage data fetching and caching
 *
 *
 * This class (DesignPattern::RemoteProxy) provides an abstract framework 
 * for loading/saving arbitrary data from/to data storages interfaced 
 * by storage *proxy*-drivers.
 * Don't mix these up with the concrete storage *handle*-drivers 
 * doing the lowlevel stuff (opening files, talking sql, etc.).
 * These proxy-drivers are "just" wrappers around them 
 * providing a more highlevel, consistent API making
 * it easier for Data::Driver::Proxy to do its main work:
 *
 * quote from: http://home.earthlink.net/~huston2/dp/proxy.html
 * "A remote proxy provides a local representative for an 
 * object that resides in a different address space. This is 
 * what the "stub" code in RPC and CORBA provides."
 *
 *
 * Multiple stage data fetching and caching:
 *
 * <pre>
 *
 * DATA, ...
 *    ... also refered to as data, should be handled as 
 *    something called data.
 *
 * STAGES
 *    x native php4 session: serialized payload
 *    x single rdbms table: serialized payload
 *       x ... via custom database wrapper
 *          x included php-file, included php-library
 *          o object, component, package, callbacks
 *       x ... via php PEAR DB abstraction objects
 *    x remote objects (items): flat attribute hash
 *       o use Data::Object::Identity
 *       o via Data::Driver::Proxy::RPC or others
 *       o Data::Object::Encoder: encodes/decodes values
 *       o Data::Object::Interpolator: interpolates/resolves references
 * 
 * WORK
 *    x move data transparently around between these stages
 *
 * TOOLS
 *
 * x Overview - Packages, Handlers and Stages:
 *     This is weird.  ;-)
 *     - A Package can be instantiated by its namespaced classname
 *       e.g.: "mkObject('My::Package');"
 *     - A Package can be a Handler for Data::Driver::Proxy
 *     - A Handler implements exactly one Stage
 *     - Data::Driver::Proxy itself embeds these Stages:
 *        x php4-session
 *        x rdbms-table
 *     - An example Handler is Data::Driver::RPC::Remote
 *
 * x Handlers:
 *    x Data::Driver::RPC::Remote
 *        Interacts with a RPC::XML server (todo: talk SOAP!) 
 *        using PEAR::XML::RPC.
 *        It can cache data for "disconnected mode" using the
 *    o Data::Driver::phpHtmlLib
 *    o Data::Driver::PEAR::DB
 *    x Data::Driver::PEAR::Tree (via Data::Lift)
 *
 * </pre>
 *
 *
 * An attempt to implement some software design patterns
 * --- RemoteProxyPattern
 *
 * @link http://www.agcs.com/supportv2/techpapers/patterns/papers/tutnotes/sld017.htm
 * @link http://home.earthlink.net/~huston2/dp/proxy.html
 * @link http://wiki.cs.uiuc.edu/PatternStories/RemoteObject
 * @link http://c2.com/cgi-bin/wiki?ProxyPattern
 * @link http://c2.com/cgi-bin/wiki?LazyProxies
 *
 * @author Andreas Motl <andreas.motl@ilo.de>
 * @link http://www.netfrag.org/~joko/
 *
 * @copyright (c) 2003 - All Rights reserved.
 * @license GNU LGPL (GNU Lesser General Public License)
 * @link http://www.gnu.org/licenses/lgpl.txt
 *
 * @package org.netfrag.glib
 * @subpackage DesignPattern
 * @name DesignPattern::RemoteProxy
 *
 *
 * @todo extend options to en-/disable caching via a) session and/or b) database
 *           make feature available via runtime setter-method to these options
 * @todo PEAR::Cache for caching purposes!!!
 * @todo refactor database access: use PEAR for this! no more 'connectdb' here!!!
 * @todo make database connection more flexible to make possible
 *           to have different (probably named) proxy databases (besides a "main database")
 * @todo rename this to Data::Proxy? or split into Data::Query, Data::Result and Data::Wrapper?
 * @todo refactor this to a "RemoteObject" class!!! (inheriting from DesignPattern::RemoteObject)
 * @todo rename this to "DesignPattern::LazyRemoteProxy"???
 *
 */
class DesignPattern_RemoteProxy extends DesignPattern_Proxy {

  var $objectId;
  // purpose ...
  var $meta;
  var $payload;
  var $attributes;
  var $backend;

  function DesignPattern_RemoteProxy($objectId = "", $options = array() ) {
    logp(get_class($this) . "->new()", PEAR_LOG_INFO);
    global $proxy;

    // 2003-03-05 - modified constructor
    // expand objectId
    if (is_array($objectId)) {
      $options = $objectId[1];
      $objectId = $objectId[0];
    }

    // trace
      //print Dumper($objectId, $options);

    // initialization/startup
      $this->_init_meta_options($objectId, $options);
      $this->_init_caching();
      $this->_init_load();

    //print Dumper($this);

  }

  function _init_meta_options( $objectId="", $options = array() ) {
    $this->meta = $options;

    if ($objectId) {
      $this->objectId = $objectId;
      
      // set default load mechanism
      if ( $this->meta[remote] && ((!$this->meta[oid] && !$this->meta[guid]) || ($this->meta[oid] && $this->meta[guid])) && (!$this->meta[key]) ) {
        $this->meta[oid] = 1;
      }
      
    }
  }

  function _init_caching() {
    
    if ($this->meta[cache][session]) {
      session_register_safe("proxy");
    }  

    /**
     * <!-- Autodia -->
     * can do: (this is metadata supplied for Autodia, don't delete!)
     *  $this->backend = new DataSource_Proxy_XMLRPC()
     *
     */

    if ($this->meta[remote]) {
      //$this->backend = mkObject('Data::Driver::RPC::Remote', $this->meta[rpcinfo]);
      $this->backend = php::mkComponent('DataSource::Proxy::XMLRPC', $this->meta[rpcinfo]);
    }
  }

  function _init_load() {
    if ($this->objectId) {
      $this->load();
      //$this->_saveProxy();
    }
  }


  function load() {
    logp(get_class($this) . "->load()", PEAR_LOG_INFO);
    if (!$this->_loadState()) {
      if (!$this->_loadProxy()) {

        // just load object from remote side if its flagged to be a remote one ...
        if ($this->meta[remote]) {
          $this->_loadRemote();
        }

      }
    }
  }  

  function save($data, $type) {
    $this->_setAttributes($data);
    $this->_saveState();
    if ($type == 'commit') {
      $this->_commit();
    }
    if ($type == 'create') {
      $this->_create();
    }
  }  

  function flush() {
    $this->flushState();
    $this->flushProxy();
  }      

  function _commit() {
    $this->_saveBackend($this->attributes);
    $this->flushState();
    $this->flushProxy();
  }  


  // TODO: make this work
  /*
  function _create() {
    $this->_createBackend($this->attributes);
    $this->flushState();
    $this->flushProxy();
  }  
  */

  function getResult() {
    if (!$this->meta[decoded]) {
      $this->_decode();
      $this->_saveState();
    }
    return $this->attributes;
  }

  function _setAttributes($data) {
    $this->attributes = $data;
  }

  function flushProxy() {
        connectdb();
    $sql = "DELETE FROM f_proxy WHERE oid='$this->objectId'";
    send_sql($sql);
  }
  
  function flushState() {
    global $proxy;
    unset($proxy[$this->objectId]);
    $this->meta[decoded] = 0;
  }

  function _loadState() {
    global $proxy;

    // trace
      //print Dumper($this);

    // debug
      logp(get_class($this) . "->_loadState()");
      
    if ($this->attributes = $proxy[$this->objectId]) {
      //print "_loadState:" . dumpVar($this->attributes);
      $this->meta[decoded] = 1;
      // TODO: make a parameter from this (0 deactivates session-layer)
      return 0;
    }
  }

  function _saveState() {
    global $proxy;
    logp(get_class($this) . "->_saveState()");
    $proxy[$this->objectId] = $this->attributes;
    //print "_saveState: " . dumpVar($this->attributes);
    // TODO: throw exception-message back to user if operation fails
  }

  function _loadProxy() {
    
    // FIXME!
    if (!$this->meta[cache][db]) { return; }
    
    // trace & debug
      //print Dumper($this);
      logp(get_class($this) . "->_loadProxy()");
      
    connectdb();
    $sql = "SELECT payload FROM f_proxy WHERE oid='$this->objectId'";
    if ($res = send_sql($sql)) {
      $row = mysql_fetch_array($res, MYSQL_ASSOC);
      if ($row) {
        $this->payload = $row[payload];
        // TODO: make a parameter from this (0 deactivates mysqldb-layer)
        return 0;
      }
    }
  }
  
  // TODO: use PEAR here
  function _saveProxy() {

    // FIXME!
    if (!$this->meta[cache][db]) { return; }

    logp(get_class($this) . "->_saveProxy()");
        connectdb();
        if ($this->payload) {
      //$sql = "INSERT INTO f_proxy SET payload='$this->payload' WHERE oid='$this->objectId'";
      $sql = "INSERT INTO f_proxy SET oid='$this->objectId', payload='$this->payload'";
      if (!send_sql($sql)) {
        $sql = "UPDATE f_proxy SET payload='$this->payload' WHERE oid='$this->objectId'";
        send_sql($sql);
      }
    }
  }
  
  function _loadRemote() {
    logp(get_class($this) . "->_loadRemote()");
    
    // trace
      //print Dumper($this->meta);
        
    // TODO: test backend for reachability first (eventually cache this information and "reset" it by another party)
    
    // 1. check backend-handle
    if (!$this->backend) {
      logp(get_class($this) . "->_loadRemote: no backend handle, please check argument 'rpcinfo'", PEAR_LOG_CRIT);
      return;
    }
    
    // determine backend action by metadata
      // check for guid or oid
      if ($this->meta[guid]) {
        if (!$this->objectId) {
          logp(get_class($this) . "->_loadRemote: argument 'guid' requires valid objectId", PEAR_LOG_WARNING);
          return;
        }
        if (!$this->meta[classname]) {
          logp(get_class($this) . "->_loadRemote: argument 'guid' requires 'classname'", PEAR_LOG_WARNING);
          return;
        }
        $args = array( guid => $this->objectId, classname => $this->meta[classname] );
        $result = $this->backend->send('getObjectByGuid', $args );

      } elseif ($this->meta[oid]) {
        if (!$this->objectId) {
          logp(get_class($this) . "->_loadRemote: argument 'oid' requires valid objectId", PEAR_LOG_WARNING);
          return;
        }
        $result = $this->backend->send('getObject', $this->objectId);

      } elseif ($this->meta[key]) {
        if (!$this->meta[command]) {
          logp(get_class($this) . "->_loadRemote: argument 'key' requires 'command'", PEAR_LOG_WARNING);
          return;
        }
        /*
        if (!$this->meta[query]) {
          logp(get_class($this) . "->_loadRemote: argument 'key' requires 'query'", PEAR_LOG_WARNING);
          return;
        }
        */
        $result = $this->backend->send($this->meta[command], $this->meta[query]);
        
      }


    if ($result) {
      //print "result: " . dumpVar($result) . "<br>";
      if (count($result) == 0) { return; }
      
      // FIXME: this is dangerous!
      if ($_GET[debug]) {
        print Dumper($result);
      }
      
      $this->payload = serialize($result);
      // ----- move this to _encode some times
      
      $this->_saveProxy();
      //print "oid: $this->objectId<br>";
      $this->flushState();
    } else {
      //print "Error in _loadRemote!!!<br>";
      logp(get_class($this) . "->_loadRemote: error while trying to talk to remote side", PEAR_LOG_CRIT);
    }
    
  }
  
  function _saveBackend($result) {
    logp(get_class($this) . "->_saveBackend()");

    //$encoder = new TextEncode($result);
    //$encoder->toUTF8();

    // check for guid or oid
    if($this->meta[guid]) {
      $args = array( 'guid' => $this->objectId, 'classname' => $this->meta[classname], 'data' => $result );
      $response = $this->backend->send('saveObjectByGuid', $args, array( utf8 => 1) );
    }
    if($this->meta[oid]) {
      $response = $this->backend->send('saveObject', array('oid' => $this->objectId, 'data' => $result), array( utf8 => 1)  );
    }
  }

  function _decode() {
    // fill attributes-hashtable from message-hashtable
    if (!$this->payload) { return; }
    //if ($this->attributes = $backend->decodeData($this->payload)) {
    if ($this->attributes = unserialize($this->payload)) {
      $this->meta[decoded] = 1;
    }
  }
  
  function store($struct) {
    $this->payload = serialize($struct);
    $this->_saveProxy();
  }

}

?>
1	joko	1.1	<?php
2	joko	1.3	/**
3			* This file contains the DesignPattern::RemoteProxy class
4			*
5			* @author Andreas Motl <andreas.motl@ilo.de>
6			* @package org.netfrag.glib
7			* @name DesignPattern::RemoteProxy
8	joko	1.4	* @filesource
9	joko	1.3	*
10	joko	1.4	*
11			* <b>Cvs-Log:</b>
12			*
13			* <pre>
14	joko	1.1	* -------------------------------------------------------------------------
15	joko	1.7	* $Id: RemoteProxy.php,v 1.6 2003/03/05 17:28:43 joko Exp $
16	joko	1.1	* -------------------------------------------------------------------------
17	joko	1.2	* $Log: RemoteProxy.php,v $
18	joko	1.7	* Revision 1.6 2003/03/05 17:28:43 joko
19			* updated docu (phpDocumentor testing....)
20			*
21	joko	1.6	* Revision 1.5 2003/03/05 17:02:22 joko
22			* updated docu (phpDocumentor testing....)
23			*
24	joko	1.5	* Revision 1.4 2003/03/05 16:32:19 joko
25			* updated docu (phpDocumentor testing....)
26			*
27	joko	1.4	* Revision 1.3 2003/03/05 16:10:17 joko
28			* updated docu (phpDocumentor testing....)
29			*
30	joko	1.3	* Revision 1.2 2003/03/05 12:14:02 joko
31			* renamed method
32			* constructor argument expansion
33			*
34	joko	1.2	* Revision 1.1 2003/03/03 22:06:46 joko
35			* refactored from Data::Driver::Proxy
36			*
37	joko	1.1	* Revision 1.3 2003/03/01 04:56:38 joko
38			* new comment style for large blocks - stolen from phpHtmlLib
39			* commit-log encapsulated into such a block
40			* introduced some documentation
41			* refactored todo (now also inside a stylish block)
42			*
43			* Revision 1.2 2003/02/13 21:48:09 joko
44			* + caching mechanisms more configurable now
45			*
46			* Revision 1.1 2003/02/09 17:23:21 joko
47			* + refactored from flib/Application/RPC/ProxyObject.php
48			*
49			* Revision 1.7 2003/02/03 03:31:38 jonen
50			* - moved '$encoder->toISO()' to 'Remote.php'
51			*
52			* Revision 1.6 2002/12/22 13:26:20 jonen
53			* + added support of tangram independent id (e.g. Data::UUID) toggled by option at conrtuctor
54			*
55			* Revision 1.5 2002/12/18 22:36:49 jonen
56			* + added support to get remote objects via backend via 'guid'
57			* + renamed '_loadBackend' to '_loadRemote'
58			* + constructor now accepts additional options:
59			* + remote: try to get object via '_loadRemote' ...
60			* + oid: use the given identifier as an 'oid' when doing '_loadRemote'
61			* + guid: use the given identifier as a 'guid' when doing '_loadRemote'
62			*
63			* Revision 1.4 2002/12/12 02:46:31 joko
64			* + state (session) gets flushed when data was successfully loaded from remote side
65			* + fixed _loadBackend
66			* + fixed flushState
67			*
68			* Revision 1.3 2002/12/06 04:12:54 joko
69			* + replaced 'xyzCache' through 'xyzProxy'
70			* + function store(...)
71			*
72			* Revision 1.2 2002/12/05 21:44:09 joko
73			* + debugging
74			*
75			* Revision 1.1 2002/12/01 17:23:58 joko
76			* + initial check-in
77			*
78			* Revision 1.11 2002/11/12 06:05:58 cvsjoko
79			* + renamed class: Text_Encode -> TextEncode
80			*
81			* Revision 1.10 2002/10/29 19:15:33 cvsjoko
82			* - moved utf8/iso-conversion to lib/utils/Text_Encode.php
83			*
84			* Revision 1.9 2002/10/26 12:32:36 cvsjoko
85			* - removed debugging via "print"
86			* + added generic logging via PEAR::Log
87			*
88			* Revision 1.8 2002/10/22 09:51:38 cvsmax
89			* + moved semi-method 'createBackend' to method $site->user->create at User.class.php
90			*
91			* Revision 1.7 2002/10/21 18:27:09 cvsjoko
92			* - manually disabled any form of caching
93			*
94			* Revision 1.6 2002/10/17 03:48:47 cvsmax
95			* + new
96			* + function _createBackend create new Backend
97			* + function _create api-create
98			*
99			* Revision 1.5 2002/10/16 03:37:54 cvsjoko
100			* + bugfix: wrong comparison in restriction to save to array
101			*
102			* Revision 1.4 2002/10/10 03:04:23 cvsjoko
103			* + no debug-output
104			*
105			* Revision 1.3 2002/10/10 03:03:27 cvsjoko
106			* + bugfix: save object to cache only if payload from backend isn't empty
107			*
108			* Revision 1.2 2002/10/10 02:40:06 cvsjoko
109			* + new level of data-caching (session and persistant)
110			* + function _loadState loads data from session
111			* + function _saveState saves data to session
112			* + function save api-save (session & backend)
113			* + function _commit saves data to backend
114			* + handy utils
115			* + function _setAttributes
116			* + function flushState
117			*
118			* Revision 1.1 2002/10/09 00:51:39 cvsjoko
119			* + new
120			* -------------------------------------------------------------------------
121	joko	1.4	* </pre>
122			*
123	joko	1.1	*/
124
125	joko	1.4
126
127
128			/**
129			* Load required modules:
130			*
131			*/
132			loadModule('DesignPattern::Proxy');
133
134
135	joko	1.1	/**
136	joko	1.7	* DesignPattern::RemoteProxy -- Multiple stage data fetching and caching
137	joko	1.1	*
138			*
139	joko	1.7	* This class (DesignPattern::RemoteProxy) provides an abstract framework
140	joko	1.1	* for loading/saving arbitrary data from/to data storages interfaced
141			* by storage proxy-drivers.
142			* Don't mix these up with the concrete storage handle-drivers
143			* doing the lowlevel stuff (opening files, talking sql, etc.).
144			* These proxy-drivers are "just" wrappers around them
145			* providing a more highlevel, consistent API making
146			* it easier for Data::Driver::Proxy to do its main work:
147			*
148	joko	1.7	* quote from: http://home.earthlink.net/~huston2/dp/proxy.html
149			* "A remote proxy provides a local representative for an
150			* object that resides in a different address space. This is
151			* what the "stub" code in RPC and CORBA provides."
152			*
153			*
154	joko	1.1	* Multiple stage data fetching and caching:
155			*
156	joko	1.4	* <pre>
157			*
158	joko	1.1	* DATA, ...
159			* ... also refered to as data, should be handled as
160			* something called data.
161			*
162			* STAGES
163			* x native php4 session: serialized payload
164			* x single rdbms table: serialized payload
165			* x ... via custom database wrapper
166			* x included php-file, included php-library
167			* o object, component, package, callbacks
168			* x ... via php PEAR DB abstraction objects
169			* x remote objects (items): flat attribute hash
170			* o use Data::Object::Identity
171			* o via Data::Driver::Proxy::RPC or others
172			* o Data::Object::Encoder: encodes/decodes values
173			* o Data::Object::Interpolator: interpolates/resolves references
174			*
175			* WORK
176			* x move data transparently around between these stages
177			*
178			* TOOLS
179			*
180			* x Overview - Packages, Handlers and Stages:
181			* This is weird. ;-)
182			* - A Package can be instantiated by its namespaced classname
183			* e.g.: "mkObject('My::Package');"
184			* - A Package can be a Handler for Data::Driver::Proxy
185			* - A Handler implements exactly one Stage
186			* - Data::Driver::Proxy itself embeds these Stages:
187			* x php4-session
188			* x rdbms-table
189			* - An example Handler is Data::Driver::RPC::Remote
190			*
191			* x Handlers:
192			* x Data::Driver::RPC::Remote
193			* Interacts with a RPC::XML server (todo: talk SOAP!)
194			* using PEAR::XML::RPC.
195			* It can cache data for "disconnected mode" using the
196			* o Data::Driver::phpHtmlLib
197			* o Data::Driver::PEAR::DB
198			* x Data::Driver::PEAR::Tree (via Data::Lift)
199			*
200	joko	1.4	* </pre>
201			*
202			*
203			* An attempt to implement some software design patterns
204	joko	1.3	* --- RemoteProxyPattern
205			*
206	joko	1.7	* @link http://www.agcs.com/supportv2/techpapers/patterns/papers/tutnotes/sld017.htm
207			* @link http://home.earthlink.net/~huston2/dp/proxy.html
208			* @link http://wiki.cs.uiuc.edu/PatternStories/RemoteObject
209	joko	1.3	* @link http://c2.com/cgi-bin/wiki?ProxyPattern
210	joko	1.7	* @link http://c2.com/cgi-bin/wiki?LazyProxies
211	joko	1.3	*
212			* @author Andreas Motl <andreas.motl@ilo.de>
213			* @link http://www.netfrag.org/~joko/
214			*
215			* @copyright (c) 2003 - All Rights reserved.
216			* @license GNU LGPL (GNU Lesser General Public License)
217			* @link http://www.gnu.org/licenses/lgpl.txt
218			*
219			* @package org.netfrag.glib
220	joko	1.6	* @subpackage DesignPattern
221	joko	1.3	* @name DesignPattern::RemoteProxy
222			*
223	joko	1.4	*
224	joko	1.7	* @todo extend options to en-/disable caching via a) session and/or b) database
225			* make feature available via runtime setter-method to these options
226			* @todo PEAR::Cache for caching purposes!!!
227			* @todo refactor database access: use PEAR for this! no more 'connectdb' here!!!
228			* @todo make database connection more flexible to make possible
229			* to have different (probably named) proxy databases (besides a "main database")
230			* @todo rename this to Data::Proxy? or split into Data::Query, Data::Result and Data::Wrapper?
231			* @todo refactor this to a "RemoteObject" class!!! (inheriting from DesignPattern::RemoteObject)
232			* @todo rename this to "DesignPattern::LazyRemoteProxy"???
233	joko	1.1	*
234			*/
235			class DesignPattern_RemoteProxy extends DesignPattern_Proxy {
236
237			var $objectId;
238			// purpose ...
239			var $meta;
240			var $payload;
241			var $attributes;
242			var $backend;
243
244			function DesignPattern_RemoteProxy($objectId = "", $options = array() ) {
245			logp(get_class($this) . "->new()", PEAR_LOG_INFO);
246			global $proxy;
247
248	joko	1.2	// 2003-03-05 - modified constructor
249			// expand objectId
250			if (is_array($objectId)) {
251			$options = $objectId[1];
252			$objectId = $objectId[0];
253			}
254
255	joko	1.1	// trace
256			//print Dumper($objectId, $options);
257
258			// initialization/startup
259			$this->_init_meta_options($objectId, $options);
260			$this->_init_caching();
261			$this->_init_load();
262
263	joko	1.2	//print Dumper($this);
264
265	joko	1.1	}
266
267			function _init_meta_options( $objectId="", $options = array() ) {
268			$this->meta = $options;
269
270			if ($objectId) {
271			$this->objectId = $objectId;
272
273			// set default load mechanism
274			if ( $this->meta[remote] && ((!$this->meta[oid] && !$this->meta[guid]) \|\| ($this->meta[oid] && $this->meta[guid])) && (!$this->meta[key]) ) {
275			$this->meta[oid] = 1;
276			}
277
278			}
279			}
280
281			function _init_caching() {
282
283			if ($this->meta[cache][session]) {
284			session_register_safe("proxy");
285			}
286	joko	1.7
287			/**
288			* <!-- Autodia -->
289			* can do: (this is metadata supplied for Autodia, don't delete!)
290			* $this->backend = new DataSource_Proxy_XMLRPC()
291			*
292			*/
293	joko	1.1
294			if ($this->meta[remote]) {
295			//$this->backend = mkObject('Data::Driver::RPC::Remote', $this->meta[rpcinfo]);
296	joko	1.2	$this->backend = php::mkComponent('DataSource::Proxy::XMLRPC', $this->meta[rpcinfo]);
297	joko	1.1	}
298			}
299
300			function _init_load() {
301			if ($this->objectId) {
302			$this->load();
303			//$this->_saveProxy();
304			}
305			}
306
307
308			function load() {
309			logp(get_class($this) . "->load()", PEAR_LOG_INFO);
310			if (!$this->_loadState()) {
311			if (!$this->_loadProxy()) {
312
313			// just load object from remote side if its flagged to be a remote one ...
314			if ($this->meta[remote]) {
315			$this->_loadRemote();
316			}
317
318			}
319			}
320			}
321
322			function save($data, $type) {
323			$this->_setAttributes($data);
324			$this->_saveState();
325			if ($type == 'commit') {
326			$this->_commit();
327			}
328			if ($type == 'create') {
329			$this->_create();
330			}
331			}
332
333			function flush() {
334			$this->flushState();
335			$this->flushProxy();
336			}
337
338			function _commit() {
339			$this->_saveBackend($this->attributes);
340			$this->flushState();
341			$this->flushProxy();
342			}
343
344
345			// TODO: make this work
346			/*
347			function _create() {
348			$this->_createBackend($this->attributes);
349			$this->flushState();
350			$this->flushProxy();
351			}
352			*/
353
354	joko	1.2	function getResult() {
355	joko	1.1	if (!$this->meta[decoded]) {
356			$this->_decode();
357			$this->_saveState();
358			}
359			return $this->attributes;
360			}
361
362			function _setAttributes($data) {
363			$this->attributes = $data;
364			}
365
366			function flushProxy() {
367			connectdb();
368			$sql = "DELETE FROM f_proxy WHERE oid='$this->objectId'";
369			send_sql($sql);
370			}
371
372			function flushState() {
373			global $proxy;
374			unset($proxy[$this->objectId]);
375			$this->meta[decoded] = 0;
376			}
377
378			function _loadState() {
379			global $proxy;
380
381			// trace
382			//print Dumper($this);
383
384			// debug
385			logp(get_class($this) . "->_loadState()");
386
387			if ($this->attributes = $proxy[$this->objectId]) {
388			//print "_loadState:" . dumpVar($this->attributes);
389			$this->meta[decoded] = 1;
390			// TODO: make a parameter from this (0 deactivates session-layer)
391			return 0;
392			}
393			}
394
395			function _saveState() {
396			global $proxy;
397			logp(get_class($this) . "->_saveState()");
398			$proxy[$this->objectId] = $this->attributes;
399			//print "_saveState: " . dumpVar($this->attributes);
400			// TODO: throw exception-message back to user if operation fails
401			}
402
403			function _loadProxy() {
404
405			// FIXME!
406			if (!$this->meta[cache][db]) { return; }
407
408			// trace & debug
409			//print Dumper($this);
410			logp(get_class($this) . "->_loadProxy()");
411
412			connectdb();
413			$sql = "SELECT payload FROM f_proxy WHERE oid='$this->objectId'";
414			if ($res = send_sql($sql)) {
415			$row = mysql_fetch_array($res, MYSQL_ASSOC);
416			if ($row) {
417			$this->payload = $row[payload];
418			// TODO: make a parameter from this (0 deactivates mysqldb-layer)
419			return 0;
420			}
421			}
422			}
423
424			// TODO: use PEAR here
425			function _saveProxy() {
426
427			// FIXME!
428			if (!$this->meta[cache][db]) { return; }
429
430			logp(get_class($this) . "->_saveProxy()");
431			connectdb();
432			if ($this->payload) {
433			//$sql = "INSERT INTO f_proxy SET payload='$this->payload' WHERE oid='$this->objectId'";
434			$sql = "INSERT INTO f_proxy SET oid='$this->objectId', payload='$this->payload'";
435			if (!send_sql($sql)) {
436			$sql = "UPDATE f_proxy SET payload='$this->payload' WHERE oid='$this->objectId'";
437			send_sql($sql);
438			}
439			}
440			}
441
442			function _loadRemote() {
443			logp(get_class($this) . "->_loadRemote()");
444
445			// trace
446			//print Dumper($this->meta);
447
448			// TODO: test backend for reachability first (eventually cache this information and "reset" it by another party)
449
450			// 1. check backend-handle
451			if (!$this->backend) {
452			logp(get_class($this) . "->_loadRemote: no backend handle, please check argument 'rpcinfo'", PEAR_LOG_CRIT);
453			return;
454			}
455
456			// determine backend action by metadata
457			// check for guid or oid
458			if ($this->meta[guid]) {
459			if (!$this->objectId) {
460			logp(get_class($this) . "->_loadRemote: argument 'guid' requires valid objectId", PEAR_LOG_WARNING);
461			return;
462			}
463			if (!$this->meta[classname]) {
464			logp(get_class($this) . "->_loadRemote: argument 'guid' requires 'classname'", PEAR_LOG_WARNING);
465			return;
466			}
467			$args = array( guid => $this->objectId, classname => $this->meta[classname] );
468			$result = $this->backend->send('getObjectByGuid', $args );
469
470			} elseif ($this->meta[oid]) {
471			if (!$this->objectId) {
472			logp(get_class($this) . "->_loadRemote: argument 'oid' requires valid objectId", PEAR_LOG_WARNING);
473			return;
474			}
475			$result = $this->backend->send('getObject', $this->objectId);
476
477			} elseif ($this->meta[key]) {
478			if (!$this->meta[command]) {
479			logp(get_class($this) . "->_loadRemote: argument 'key' requires 'command'", PEAR_LOG_WARNING);
480			return;
481			}
482			/*
483			if (!$this->meta[query]) {
484			logp(get_class($this) . "->_loadRemote: argument 'key' requires 'query'", PEAR_LOG_WARNING);
485			return;
486			}
487			*/
488			$result = $this->backend->send($this->meta[command], $this->meta[query]);
489
490			}
491
492
493
494			if ($result) {
495			//print "result: " . dumpVar($result) . "<br>";
496			if (count($result) == 0) { return; }
497
498			// FIXME: this is dangerous!
499			if ($_GET[debug]) {
500			print Dumper($result);
501			}
502
503			$this->payload = serialize($result);
504			// ----- move this to _encode some times
505
506			$this->_saveProxy();
507			//print "oid: $this->objectId<br>";
508			$this->flushState();
509			} else {
510			//print "Error in _loadRemote!!!<br>";
511			logp(get_class($this) . "->_loadRemote: error while trying to talk to remote side", PEAR_LOG_CRIT);
512			}
513
514			}
515
516			function _saveBackend($result) {
517			logp(get_class($this) . "->_saveBackend()");
518
519			//$encoder = new TextEncode($result);
520			//$encoder->toUTF8();
521
522			// check for guid or oid
523			if($this->meta[guid]) {
524			$args = array( 'guid' => $this->objectId, 'classname' => $this->meta[classname], 'data' => $result );
525			$response = $this->backend->send('saveObjectByGuid', $args, array( utf8 => 1) );
526			}
527			if($this->meta[oid]) {
528			$response = $this->backend->send('saveObject', array('oid' => $this->objectId, 'data' => $result), array( utf8 => 1) );
529			}
530			}
531
532			function _decode() {
533			// fill attributes-hashtable from message-hashtable
534			if (!$this->payload) { return; }
535			//if ($this->attributes = $backend->decodeData($this->payload)) {
536			if ($this->attributes = unserialize($this->payload)) {
537			$this->meta[decoded] = 1;
538			}
539			}
540
541			function store($struct) {
542			$this->payload = serialize($struct);
543			$this->_saveProxy();
544			}
545
546			}
547
548			?>
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