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
 *
 *
 * <b>Cvs-Log:</b>
 *
 * <pre>
 * -------------------------------------------------------------------------
 *    $Id: RemoteProxy.php,v 1.7 2003/03/09 15:51:44 joko Exp $
 * -------------------------------------------------------------------------
 *    $Log: RemoteProxy.php,v $
 *    Revision 1.7  2003/03/09 15:51:44  joko
 *    + additional metadata for Autodia
 *
 *    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			*
9	joko	1.4	*
10			* <b>Cvs-Log:</b>
11			*
12			* <pre>
13	joko	1.1	* -------------------------------------------------------------------------
14	joko	1.8	* $Id: RemoteProxy.php,v 1.7 2003/03/09 15:51:44 joko Exp $
15	joko	1.1	* -------------------------------------------------------------------------
16	joko	1.2	* $Log: RemoteProxy.php,v $
17	joko	1.8	* Revision 1.7 2003/03/09 15:51:44 joko
18			* + additional metadata for Autodia
19			*
20	joko	1.7	* Revision 1.6 2003/03/05 17:28:43 joko
21			* updated docu (phpDocumentor testing....)
22			*
23	joko	1.6	* Revision 1.5 2003/03/05 17:02:22 joko
24			* updated docu (phpDocumentor testing....)
25			*
26	joko	1.5	* Revision 1.4 2003/03/05 16:32:19 joko
27			* updated docu (phpDocumentor testing....)
28			*
29	joko	1.4	* Revision 1.3 2003/03/05 16:10:17 joko
30			* updated docu (phpDocumentor testing....)
31			*
32	joko	1.3	* Revision 1.2 2003/03/05 12:14:02 joko
33			* renamed method
34			* constructor argument expansion
35			*
36	joko	1.2	* Revision 1.1 2003/03/03 22:06:46 joko
37			* refactored from Data::Driver::Proxy
38			*
39	joko	1.1	* Revision 1.3 2003/03/01 04:56:38 joko
40			* new comment style for large blocks - stolen from phpHtmlLib
41			* commit-log encapsulated into such a block
42			* introduced some documentation
43			* refactored todo (now also inside a stylish block)
44			*
45			* Revision 1.2 2003/02/13 21:48:09 joko
46			* + caching mechanisms more configurable now
47			*
48			* Revision 1.1 2003/02/09 17:23:21 joko
49			* + refactored from flib/Application/RPC/ProxyObject.php
50			*
51			* Revision 1.7 2003/02/03 03:31:38 jonen
52			* - moved '$encoder->toISO()' to 'Remote.php'
53			*
54			* Revision 1.6 2002/12/22 13:26:20 jonen
55			* + added support of tangram independent id (e.g. Data::UUID) toggled by option at conrtuctor
56			*
57			* Revision 1.5 2002/12/18 22:36:49 jonen
58			* + added support to get remote objects via backend via 'guid'
59			* + renamed '_loadBackend' to '_loadRemote'
60			* + constructor now accepts additional options:
61			* + remote: try to get object via '_loadRemote' ...
62			* + oid: use the given identifier as an 'oid' when doing '_loadRemote'
63			* + guid: use the given identifier as a 'guid' when doing '_loadRemote'
64			*
65			* Revision 1.4 2002/12/12 02:46:31 joko
66			* + state (session) gets flushed when data was successfully loaded from remote side
67			* + fixed _loadBackend
68			* + fixed flushState
69			*
70			* Revision 1.3 2002/12/06 04:12:54 joko
71			* + replaced 'xyzCache' through 'xyzProxy'
72			* + function store(...)
73			*
74			* Revision 1.2 2002/12/05 21:44:09 joko
75			* + debugging
76			*
77			* Revision 1.1 2002/12/01 17:23:58 joko
78			* + initial check-in
79			*
80			* Revision 1.11 2002/11/12 06:05:58 cvsjoko
81			* + renamed class: Text_Encode -> TextEncode
82			*
83			* Revision 1.10 2002/10/29 19:15:33 cvsjoko
84			* - moved utf8/iso-conversion to lib/utils/Text_Encode.php
85			*
86			* Revision 1.9 2002/10/26 12:32:36 cvsjoko
87			* - removed debugging via "print"
88			* + added generic logging via PEAR::Log
89			*
90			* Revision 1.8 2002/10/22 09:51:38 cvsmax
91			* + moved semi-method 'createBackend' to method $site->user->create at User.class.php
92			*
93			* Revision 1.7 2002/10/21 18:27:09 cvsjoko
94			* - manually disabled any form of caching
95			*
96			* Revision 1.6 2002/10/17 03:48:47 cvsmax
97			* + new
98			* + function _createBackend create new Backend
99			* + function _create api-create
100			*
101			* Revision 1.5 2002/10/16 03:37:54 cvsjoko
102			* + bugfix: wrong comparison in restriction to save to array
103			*
104			* Revision 1.4 2002/10/10 03:04:23 cvsjoko
105			* + no debug-output
106			*
107			* Revision 1.3 2002/10/10 03:03:27 cvsjoko
108			* + bugfix: save object to cache only if payload from backend isn't empty
109			*
110			* Revision 1.2 2002/10/10 02:40:06 cvsjoko
111			* + new level of data-caching (session and persistant)
112			* + function _loadState loads data from session
113			* + function _saveState saves data to session
114			* + function save api-save (session & backend)
115			* + function _commit saves data to backend
116			* + handy utils
117			* + function _setAttributes
118			* + function flushState
119			*
120			* Revision 1.1 2002/10/09 00:51:39 cvsjoko
121			* + new
122			* -------------------------------------------------------------------------
123	joko	1.4	* </pre>
124			*
125	joko	1.1	*/
126
127	joko	1.4
128
129
130			/**
131			* Load required modules:
132			*
133			*/
134			loadModule('DesignPattern::Proxy');
135
136
137	joko	1.1	/**
138	joko	1.7	* DesignPattern::RemoteProxy -- Multiple stage data fetching and caching
139	joko	1.1	*
140			*
141	joko	1.7	* This class (DesignPattern::RemoteProxy) provides an abstract framework
142	joko	1.1	* for loading/saving arbitrary data from/to data storages interfaced
143			* by storage proxy-drivers.
144			* Don't mix these up with the concrete storage handle-drivers
145			* doing the lowlevel stuff (opening files, talking sql, etc.).
146			* These proxy-drivers are "just" wrappers around them
147			* providing a more highlevel, consistent API making
148			* it easier for Data::Driver::Proxy to do its main work:
149			*
150	joko	1.7	* quote from: http://home.earthlink.net/~huston2/dp/proxy.html
151			* "A remote proxy provides a local representative for an
152			* object that resides in a different address space. This is
153			* what the "stub" code in RPC and CORBA provides."
154			*
155			*
156	joko	1.1	* Multiple stage data fetching and caching:
157			*
158	joko	1.4	* <pre>
159			*
160	joko	1.1	* DATA, ...
161			* ... also refered to as data, should be handled as
162			* something called data.
163			*
164			* STAGES
165			* x native php4 session: serialized payload
166			* x single rdbms table: serialized payload
167			* x ... via custom database wrapper
168			* x included php-file, included php-library
169			* o object, component, package, callbacks
170			* x ... via php PEAR DB abstraction objects
171			* x remote objects (items): flat attribute hash
172			* o use Data::Object::Identity
173			* o via Data::Driver::Proxy::RPC or others
174			* o Data::Object::Encoder: encodes/decodes values
175			* o Data::Object::Interpolator: interpolates/resolves references
176			*
177			* WORK
178			* x move data transparently around between these stages
179			*
180			* TOOLS
181			*
182			* x Overview - Packages, Handlers and Stages:
183			* This is weird. ;-)
184			* - A Package can be instantiated by its namespaced classname
185			* e.g.: "mkObject('My::Package');"
186			* - A Package can be a Handler for Data::Driver::Proxy
187			* - A Handler implements exactly one Stage
188			* - Data::Driver::Proxy itself embeds these Stages:
189			* x php4-session
190			* x rdbms-table
191			* - An example Handler is Data::Driver::RPC::Remote
192			*
193			* x Handlers:
194			* x Data::Driver::RPC::Remote
195			* Interacts with a RPC::XML server (todo: talk SOAP!)
196			* using PEAR::XML::RPC.
197			* It can cache data for "disconnected mode" using the
198			* o Data::Driver::phpHtmlLib
199			* o Data::Driver::PEAR::DB
200			* x Data::Driver::PEAR::Tree (via Data::Lift)
201			*
202	joko	1.4	* </pre>
203			*
204			*
205			* An attempt to implement some software design patterns
206	joko	1.3	* --- RemoteProxyPattern
207			*
208	joko	1.7	* @link http://www.agcs.com/supportv2/techpapers/patterns/papers/tutnotes/sld017.htm
209			* @link http://home.earthlink.net/~huston2/dp/proxy.html
210			* @link http://wiki.cs.uiuc.edu/PatternStories/RemoteObject
211	joko	1.3	* @link http://c2.com/cgi-bin/wiki?ProxyPattern
212	joko	1.7	* @link http://c2.com/cgi-bin/wiki?LazyProxies
213	joko	1.3	*
214			* @author Andreas Motl <andreas.motl@ilo.de>
215			* @link http://www.netfrag.org/~joko/
216			*
217			* @copyright (c) 2003 - All Rights reserved.
218			* @license GNU LGPL (GNU Lesser General Public License)
219			* @link http://www.gnu.org/licenses/lgpl.txt
220			*
221			* @package org.netfrag.glib
222	joko	1.6	* @subpackage DesignPattern
223	joko	1.3	* @name DesignPattern::RemoteProxy
224			*
225	joko	1.4	*
226	joko	1.7	* @todo extend options to en-/disable caching via a) session and/or b) database
227			* make feature available via runtime setter-method to these options
228			* @todo PEAR::Cache for caching purposes!!!
229			* @todo refactor database access: use PEAR for this! no more 'connectdb' here!!!
230			* @todo make database connection more flexible to make possible
231			* to have different (probably named) proxy databases (besides a "main database")
232			* @todo rename this to Data::Proxy? or split into Data::Query, Data::Result and Data::Wrapper?
233			* @todo refactor this to a "RemoteObject" class!!! (inheriting from DesignPattern::RemoteObject)
234			* @todo rename this to "DesignPattern::LazyRemoteProxy"???
235	joko	1.1	*
236			*/
237			class DesignPattern_RemoteProxy extends DesignPattern_Proxy {
238
239			var $objectId;
240			// purpose ...
241			var $meta;
242			var $payload;
243			var $attributes;
244			var $backend;
245
246			function DesignPattern_RemoteProxy($objectId = "", $options = array() ) {
247			logp(get_class($this) . "->new()", PEAR_LOG_INFO);
248			global $proxy;
249
250	joko	1.2	// 2003-03-05 - modified constructor
251			// expand objectId
252			if (is_array($objectId)) {
253			$options = $objectId[1];
254			$objectId = $objectId[0];
255			}
256
257	joko	1.1	// trace
258			//print Dumper($objectId, $options);
259
260			// initialization/startup
261			$this->_init_meta_options($objectId, $options);
262			$this->_init_caching();
263			$this->_init_load();
264
265	joko	1.2	//print Dumper($this);
266
267	joko	1.1	}
268
269			function _init_meta_options( $objectId="", $options = array() ) {
270			$this->meta = $options;
271
272			if ($objectId) {
273			$this->objectId = $objectId;
274
275			// set default load mechanism
276			if ( $this->meta[remote] && ((!$this->meta[oid] && !$this->meta[guid]) \|\| ($this->meta[oid] && $this->meta[guid])) && (!$this->meta[key]) ) {
277			$this->meta[oid] = 1;
278			}
279
280			}
281			}
282
283			function _init_caching() {
284
285			if ($this->meta[cache][session]) {
286			session_register_safe("proxy");
287			}
288	joko	1.7
289			/**
290			* <!-- Autodia -->
291			* can do: (this is metadata supplied for Autodia, don't delete!)
292			* $this->backend = new DataSource_Proxy_XMLRPC()
293			*
294			*/
295	joko	1.1
296			if ($this->meta[remote]) {
297			//$this->backend = mkObject('Data::Driver::RPC::Remote', $this->meta[rpcinfo]);
298	joko	1.2	$this->backend = php::mkComponent('DataSource::Proxy::XMLRPC', $this->meta[rpcinfo]);
299	joko	1.1	}
300			}
301
302			function _init_load() {
303			if ($this->objectId) {
304			$this->load();
305			//$this->_saveProxy();
306			}
307			}
308
309
310			function load() {
311			logp(get_class($this) . "->load()", PEAR_LOG_INFO);
312			if (!$this->_loadState()) {
313			if (!$this->_loadProxy()) {
314
315			// just load object from remote side if its flagged to be a remote one ...
316			if ($this->meta[remote]) {
317			$this->_loadRemote();
318			}
319
320			}
321			}
322			}
323
324			function save($data, $type) {
325			$this->_setAttributes($data);
326			$this->_saveState();
327			if ($type == 'commit') {
328			$this->_commit();
329			}
330			if ($type == 'create') {
331			$this->_create();
332			}
333			}
334
335			function flush() {
336			$this->flushState();
337			$this->flushProxy();
338			}
339
340			function _commit() {
341			$this->_saveBackend($this->attributes);
342			$this->flushState();
343			$this->flushProxy();
344			}
345
346
347			// TODO: make this work
348			/*
349			function _create() {
350			$this->_createBackend($this->attributes);
351			$this->flushState();
352			$this->flushProxy();
353			}
354			*/
355
356	joko	1.2	function getResult() {
357	joko	1.1	if (!$this->meta[decoded]) {
358			$this->_decode();
359			$this->_saveState();
360			}
361			return $this->attributes;
362			}
363
364			function _setAttributes($data) {
365			$this->attributes = $data;
366			}
367
368			function flushProxy() {
369			connectdb();
370			$sql = "DELETE FROM f_proxy WHERE oid='$this->objectId'";
371			send_sql($sql);
372			}
373
374			function flushState() {
375			global $proxy;
376			unset($proxy[$this->objectId]);
377			$this->meta[decoded] = 0;
378			}
379
380			function _loadState() {
381			global $proxy;
382
383			// trace
384			//print Dumper($this);
385
386			// debug
387			logp(get_class($this) . "->_loadState()");
388
389			if ($this->attributes = $proxy[$this->objectId]) {
390			//print "_loadState:" . dumpVar($this->attributes);
391			$this->meta[decoded] = 1;
392			// TODO: make a parameter from this (0 deactivates session-layer)
393			return 0;
394			}
395			}
396
397			function _saveState() {
398			global $proxy;
399			logp(get_class($this) . "->_saveState()");
400			$proxy[$this->objectId] = $this->attributes;
401			//print "_saveState: " . dumpVar($this->attributes);
402			// TODO: throw exception-message back to user if operation fails
403			}
404
405			function _loadProxy() {
406
407			// FIXME!
408			if (!$this->meta[cache][db]) { return; }
409
410			// trace & debug
411			//print Dumper($this);
412			logp(get_class($this) . "->_loadProxy()");
413
414			connectdb();
415			$sql = "SELECT payload FROM f_proxy WHERE oid='$this->objectId'";
416			if ($res = send_sql($sql)) {
417			$row = mysql_fetch_array($res, MYSQL_ASSOC);
418			if ($row) {
419			$this->payload = $row[payload];
420			// TODO: make a parameter from this (0 deactivates mysqldb-layer)
421			return 0;
422			}
423			}
424			}
425
426			// TODO: use PEAR here
427			function _saveProxy() {
428
429			// FIXME!
430			if (!$this->meta[cache][db]) { return; }
431
432			logp(get_class($this) . "->_saveProxy()");
433			connectdb();
434			if ($this->payload) {
435			//$sql = "INSERT INTO f_proxy SET payload='$this->payload' WHERE oid='$this->objectId'";
436			$sql = "INSERT INTO f_proxy SET oid='$this->objectId', payload='$this->payload'";
437			if (!send_sql($sql)) {
438			$sql = "UPDATE f_proxy SET payload='$this->payload' WHERE oid='$this->objectId'";
439			send_sql($sql);
440			}
441			}
442			}
443
444			function _loadRemote() {
445			logp(get_class($this) . "->_loadRemote()");
446
447			// trace
448			//print Dumper($this->meta);
449
450			// TODO: test backend for reachability first (eventually cache this information and "reset" it by another party)
451
452			// 1. check backend-handle
453			if (!$this->backend) {
454			logp(get_class($this) . "->_loadRemote: no backend handle, please check argument 'rpcinfo'", PEAR_LOG_CRIT);
455			return;
456			}
457
458			// determine backend action by metadata
459			// check for guid or oid
460			if ($this->meta[guid]) {
461			if (!$this->objectId) {
462			logp(get_class($this) . "->_loadRemote: argument 'guid' requires valid objectId", PEAR_LOG_WARNING);
463			return;
464			}
465			if (!$this->meta[classname]) {
466			logp(get_class($this) . "->_loadRemote: argument 'guid' requires 'classname'", PEAR_LOG_WARNING);
467			return;
468			}
469			$args = array( guid => $this->objectId, classname => $this->meta[classname] );
470			$result = $this->backend->send('getObjectByGuid', $args );
471
472			} elseif ($this->meta[oid]) {
473			if (!$this->objectId) {
474			logp(get_class($this) . "->_loadRemote: argument 'oid' requires valid objectId", PEAR_LOG_WARNING);
475			return;
476			}
477			$result = $this->backend->send('getObject', $this->objectId);
478
479			} elseif ($this->meta[key]) {
480			if (!$this->meta[command]) {
481			logp(get_class($this) . "->_loadRemote: argument 'key' requires 'command'", PEAR_LOG_WARNING);
482			return;
483			}
484			/*
485			if (!$this->meta[query]) {
486			logp(get_class($this) . "->_loadRemote: argument 'key' requires 'query'", PEAR_LOG_WARNING);
487			return;
488			}
489			*/
490			$result = $this->backend->send($this->meta[command], $this->meta[query]);
491
492			}
493
494
495
496			if ($result) {
497			//print "result: " . dumpVar($result) . "<br>";
498			if (count($result) == 0) { return; }
499
500			// FIXME: this is dangerous!
501			if ($_GET[debug]) {
502			print Dumper($result);
503			}
504
505			$this->payload = serialize($result);
506			// ----- move this to _encode some times
507
508			$this->_saveProxy();
509			//print "oid: $this->objectId<br>";
510			$this->flushState();
511			} else {
512			//print "Error in _loadRemote!!!<br>";
513			logp(get_class($this) . "->_loadRemote: error while trying to talk to remote side", PEAR_LOG_CRIT);
514			}
515
516			}
517
518			function _saveBackend($result) {
519			logp(get_class($this) . "->_saveBackend()");
520
521			//$encoder = new TextEncode($result);
522			//$encoder->toUTF8();
523
524			// check for guid or oid
525			if($this->meta[guid]) {
526			$args = array( 'guid' => $this->objectId, 'classname' => $this->meta[classname], 'data' => $result );
527			$response = $this->backend->send('saveObjectByGuid', $args, array( utf8 => 1) );
528			}
529			if($this->meta[oid]) {
530			$response = $this->backend->send('saveObject', array('oid' => $this->objectId, 'data' => $result), array( utf8 => 1) );
531			}
532			}
533
534			function _decode() {
535			// fill attributes-hashtable from message-hashtable
536			if (!$this->payload) { return; }
537			//if ($this->attributes = $backend->decodeData($this->payload)) {
538			if ($this->attributes = unserialize($this->payload)) {
539			$this->meta[decoded] = 1;
540			}
541			}
542
543			function store($struct) {
544			$this->payload = serialize($struct);
545			$this->_saveProxy();
546			}
547
548			}
549
550			?>
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