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 1.8 2003/03/10 22:31:56 joko Exp $
 * -------------------------------------------------------------------------
 *    $Log: RemoteProxy.php,v $
 *    Revision 1.8  2003/03/10 22:31:56  joko
 *    + fixed metadata for phpDocumentor
 *
 *    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	joko	1.9	*/
11
12
13			/**
14	joko	1.4	* <b>Cvs-Log:</b>
15			*
16			* <pre>
17	joko	1.1	* -------------------------------------------------------------------------
18	joko	1.9	* $Id: RemoteProxy.php,v 1.8 2003/03/10 22:31:56 joko Exp $
19	joko	1.1	* -------------------------------------------------------------------------
20	joko	1.2	* $Log: RemoteProxy.php,v $
21	joko	1.9	* Revision 1.8 2003/03/10 22:31:56 joko
22			* + fixed metadata for phpDocumentor
23			*
24	joko	1.8	* Revision 1.7 2003/03/09 15:51:44 joko
25			* + additional metadata for Autodia
26			*
27	joko	1.7	* Revision 1.6 2003/03/05 17:28:43 joko
28			* updated docu (phpDocumentor testing....)
29			*
30	joko	1.6	* Revision 1.5 2003/03/05 17:02:22 joko
31			* updated docu (phpDocumentor testing....)
32			*
33	joko	1.5	* Revision 1.4 2003/03/05 16:32:19 joko
34			* updated docu (phpDocumentor testing....)
35			*
36	joko	1.4	* Revision 1.3 2003/03/05 16:10:17 joko
37			* updated docu (phpDocumentor testing....)
38			*
39	joko	1.3	* Revision 1.2 2003/03/05 12:14:02 joko
40			* renamed method
41			* constructor argument expansion
42			*
43	joko	1.2	* Revision 1.1 2003/03/03 22:06:46 joko
44			* refactored from Data::Driver::Proxy
45			*
46	joko	1.1	* Revision 1.3 2003/03/01 04:56:38 joko
47			* new comment style for large blocks - stolen from phpHtmlLib
48			* commit-log encapsulated into such a block
49			* introduced some documentation
50			* refactored todo (now also inside a stylish block)
51			*
52			* Revision 1.2 2003/02/13 21:48:09 joko
53			* + caching mechanisms more configurable now
54			*
55			* Revision 1.1 2003/02/09 17:23:21 joko
56			* + refactored from flib/Application/RPC/ProxyObject.php
57			*
58			* Revision 1.7 2003/02/03 03:31:38 jonen
59			* - moved '$encoder->toISO()' to 'Remote.php'
60			*
61			* Revision 1.6 2002/12/22 13:26:20 jonen
62			* + added support of tangram independent id (e.g. Data::UUID) toggled by option at conrtuctor
63			*
64			* Revision 1.5 2002/12/18 22:36:49 jonen
65			* + added support to get remote objects via backend via 'guid'
66			* + renamed '_loadBackend' to '_loadRemote'
67			* + constructor now accepts additional options:
68			* + remote: try to get object via '_loadRemote' ...
69			* + oid: use the given identifier as an 'oid' when doing '_loadRemote'
70			* + guid: use the given identifier as a 'guid' when doing '_loadRemote'
71			*
72			* Revision 1.4 2002/12/12 02:46:31 joko
73			* + state (session) gets flushed when data was successfully loaded from remote side
74			* + fixed _loadBackend
75			* + fixed flushState
76			*
77			* Revision 1.3 2002/12/06 04:12:54 joko
78			* + replaced 'xyzCache' through 'xyzProxy'
79			* + function store(...)
80			*
81			* Revision 1.2 2002/12/05 21:44:09 joko
82			* + debugging
83			*
84			* Revision 1.1 2002/12/01 17:23:58 joko
85			* + initial check-in
86			*
87			* Revision 1.11 2002/11/12 06:05:58 cvsjoko
88			* + renamed class: Text_Encode -> TextEncode
89			*
90			* Revision 1.10 2002/10/29 19:15:33 cvsjoko
91			* - moved utf8/iso-conversion to lib/utils/Text_Encode.php
92			*
93			* Revision 1.9 2002/10/26 12:32:36 cvsjoko
94			* - removed debugging via "print"
95			* + added generic logging via PEAR::Log
96			*
97			* Revision 1.8 2002/10/22 09:51:38 cvsmax
98			* + moved semi-method 'createBackend' to method $site->user->create at User.class.php
99			*
100			* Revision 1.7 2002/10/21 18:27:09 cvsjoko
101			* - manually disabled any form of caching
102			*
103			* Revision 1.6 2002/10/17 03:48:47 cvsmax
104			* + new
105			* + function _createBackend create new Backend
106			* + function _create api-create
107			*
108			* Revision 1.5 2002/10/16 03:37:54 cvsjoko
109			* + bugfix: wrong comparison in restriction to save to array
110			*
111			* Revision 1.4 2002/10/10 03:04:23 cvsjoko
112			* + no debug-output
113			*
114			* Revision 1.3 2002/10/10 03:03:27 cvsjoko
115			* + bugfix: save object to cache only if payload from backend isn't empty
116			*
117			* Revision 1.2 2002/10/10 02:40:06 cvsjoko
118			* + new level of data-caching (session and persistant)
119			* + function _loadState loads data from session
120			* + function _saveState saves data to session
121			* + function save api-save (session & backend)
122			* + function _commit saves data to backend
123			* + handy utils
124			* + function _setAttributes
125			* + function flushState
126			*
127			* Revision 1.1 2002/10/09 00:51:39 cvsjoko
128			* + new
129			* -------------------------------------------------------------------------
130	joko	1.4	* </pre>
131			*
132	joko	1.1	*/
133
134	joko	1.4
135
136
137			/**
138			* Load required modules:
139			*
140			*/
141			loadModule('DesignPattern::Proxy');
142
143
144	joko	1.1	/**
145	joko	1.7	* DesignPattern::RemoteProxy -- Multiple stage data fetching and caching
146	joko	1.1	*
147			*
148	joko	1.7	* This class (DesignPattern::RemoteProxy) provides an abstract framework
149	joko	1.1	* for loading/saving arbitrary data from/to data storages interfaced
150			* by storage proxy-drivers.
151			* Don't mix these up with the concrete storage handle-drivers
152			* doing the lowlevel stuff (opening files, talking sql, etc.).
153			* These proxy-drivers are "just" wrappers around them
154			* providing a more highlevel, consistent API making
155			* it easier for Data::Driver::Proxy to do its main work:
156			*
157	joko	1.7	* quote from: http://home.earthlink.net/~huston2/dp/proxy.html
158			* "A remote proxy provides a local representative for an
159			* object that resides in a different address space. This is
160			* what the "stub" code in RPC and CORBA provides."
161			*
162			*
163	joko	1.1	* Multiple stage data fetching and caching:
164			*
165	joko	1.4	* <pre>
166			*
167	joko	1.1	* DATA, ...
168			* ... also refered to as data, should be handled as
169			* something called data.
170			*
171			* STAGES
172			* x native php4 session: serialized payload
173			* x single rdbms table: serialized payload
174			* x ... via custom database wrapper
175			* x included php-file, included php-library
176			* o object, component, package, callbacks
177			* x ... via php PEAR DB abstraction objects
178			* x remote objects (items): flat attribute hash
179			* o use Data::Object::Identity
180			* o via Data::Driver::Proxy::RPC or others
181			* o Data::Object::Encoder: encodes/decodes values
182			* o Data::Object::Interpolator: interpolates/resolves references
183			*
184			* WORK
185			* x move data transparently around between these stages
186			*
187			* TOOLS
188			*
189			* x Overview - Packages, Handlers and Stages:
190			* This is weird. ;-)
191			* - A Package can be instantiated by its namespaced classname
192			* e.g.: "mkObject('My::Package');"
193			* - A Package can be a Handler for Data::Driver::Proxy
194			* - A Handler implements exactly one Stage
195			* - Data::Driver::Proxy itself embeds these Stages:
196			* x php4-session
197			* x rdbms-table
198			* - An example Handler is Data::Driver::RPC::Remote
199			*
200			* x Handlers:
201			* x Data::Driver::RPC::Remote
202			* Interacts with a RPC::XML server (todo: talk SOAP!)
203			* using PEAR::XML::RPC.
204			* It can cache data for "disconnected mode" using the
205			* o Data::Driver::phpHtmlLib
206			* o Data::Driver::PEAR::DB
207			* x Data::Driver::PEAR::Tree (via Data::Lift)
208			*
209	joko	1.4	* </pre>
210			*
211			*
212			* An attempt to implement some software design patterns
213	joko	1.3	* --- RemoteProxyPattern
214			*
215	joko	1.7	* @link http://www.agcs.com/supportv2/techpapers/patterns/papers/tutnotes/sld017.htm
216			* @link http://home.earthlink.net/~huston2/dp/proxy.html
217			* @link http://wiki.cs.uiuc.edu/PatternStories/RemoteObject
218	joko	1.3	* @link http://c2.com/cgi-bin/wiki?ProxyPattern
219	joko	1.7	* @link http://c2.com/cgi-bin/wiki?LazyProxies
220	joko	1.3	*
221			* @author Andreas Motl <andreas.motl@ilo.de>
222			* @link http://www.netfrag.org/~joko/
223			*
224			* @copyright (c) 2003 - All Rights reserved.
225			* @license GNU LGPL (GNU Lesser General Public License)
226			* @link http://www.gnu.org/licenses/lgpl.txt
227			*
228			* @package org.netfrag.glib
229	joko	1.6	* @subpackage DesignPattern
230	joko	1.3	* @name DesignPattern::RemoteProxy
231			*
232	joko	1.4	*
233	joko	1.7	* @todo extend options to en-/disable caching via a) session and/or b) database
234			* make feature available via runtime setter-method to these options
235			* @todo PEAR::Cache for caching purposes!!!
236			* @todo refactor database access: use PEAR for this! no more 'connectdb' here!!!
237			* @todo make database connection more flexible to make possible
238			* to have different (probably named) proxy databases (besides a "main database")
239			* @todo rename this to Data::Proxy? or split into Data::Query, Data::Result and Data::Wrapper?
240			* @todo refactor this to a "RemoteObject" class!!! (inheriting from DesignPattern::RemoteObject)
241			* @todo rename this to "DesignPattern::LazyRemoteProxy"???
242	joko	1.1	*
243			*/
244			class DesignPattern_RemoteProxy extends DesignPattern_Proxy {
245
246			var $objectId;
247			// purpose ...
248			var $meta;
249			var $payload;
250			var $attributes;
251			var $backend;
252
253			function DesignPattern_RemoteProxy($objectId = "", $options = array() ) {
254			logp(get_class($this) . "->new()", PEAR_LOG_INFO);
255			global $proxy;
256
257	joko	1.2	// 2003-03-05 - modified constructor
258			// expand objectId
259			if (is_array($objectId)) {
260			$options = $objectId[1];
261			$objectId = $objectId[0];
262			}
263
264	joko	1.1	// trace
265			//print Dumper($objectId, $options);
266
267			// initialization/startup
268			$this->_init_meta_options($objectId, $options);
269			$this->_init_caching();
270			$this->_init_load();
271
272	joko	1.2	//print Dumper($this);
273
274	joko	1.1	}
275
276			function _init_meta_options( $objectId="", $options = array() ) {
277			$this->meta = $options;
278
279			if ($objectId) {
280			$this->objectId = $objectId;
281
282			// set default load mechanism
283			if ( $this->meta[remote] && ((!$this->meta[oid] && !$this->meta[guid]) \|\| ($this->meta[oid] && $this->meta[guid])) && (!$this->meta[key]) ) {
284			$this->meta[oid] = 1;
285			}
286
287			}
288			}
289
290			function _init_caching() {
291
292			if ($this->meta[cache][session]) {
293			session_register_safe("proxy");
294			}
295	joko	1.7
296			/**
297			* <!-- Autodia -->
298			* can do: (this is metadata supplied for Autodia, don't delete!)
299			* $this->backend = new DataSource_Proxy_XMLRPC()
300			*
301			*/
302	joko	1.1
303			if ($this->meta[remote]) {
304			//$this->backend = mkObject('Data::Driver::RPC::Remote', $this->meta[rpcinfo]);
305	joko	1.2	$this->backend = php::mkComponent('DataSource::Proxy::XMLRPC', $this->meta[rpcinfo]);
306	joko	1.1	}
307			}
308
309			function _init_load() {
310			if ($this->objectId) {
311			$this->load();
312			//$this->_saveProxy();
313			}
314			}
315
316
317			function load() {
318			logp(get_class($this) . "->load()", PEAR_LOG_INFO);
319			if (!$this->_loadState()) {
320			if (!$this->_loadProxy()) {
321
322			// just load object from remote side if its flagged to be a remote one ...
323			if ($this->meta[remote]) {
324			$this->_loadRemote();
325			}
326
327			}
328			}
329			}
330
331			function save($data, $type) {
332			$this->_setAttributes($data);
333			$this->_saveState();
334			if ($type == 'commit') {
335			$this->_commit();
336			}
337			if ($type == 'create') {
338			$this->_create();
339			}
340			}
341
342			function flush() {
343			$this->flushState();
344			$this->flushProxy();
345			}
346
347			function _commit() {
348			$this->_saveBackend($this->attributes);
349			$this->flushState();
350			$this->flushProxy();
351			}
352
353
354			// TODO: make this work
355			/*
356			function _create() {
357			$this->_createBackend($this->attributes);
358			$this->flushState();
359			$this->flushProxy();
360			}
361			*/
362
363	joko	1.2	function getResult() {
364	joko	1.1	if (!$this->meta[decoded]) {
365			$this->_decode();
366			$this->_saveState();
367			}
368			return $this->attributes;
369			}
370
371			function _setAttributes($data) {
372			$this->attributes = $data;
373			}
374
375			function flushProxy() {
376			connectdb();
377			$sql = "DELETE FROM f_proxy WHERE oid='$this->objectId'";
378			send_sql($sql);
379			}
380
381			function flushState() {
382			global $proxy;
383			unset($proxy[$this->objectId]);
384			$this->meta[decoded] = 0;
385			}
386
387			function _loadState() {
388			global $proxy;
389
390			// trace
391			//print Dumper($this);
392
393			// debug
394			logp(get_class($this) . "->_loadState()");
395
396			if ($this->attributes = $proxy[$this->objectId]) {
397			//print "_loadState:" . dumpVar($this->attributes);
398			$this->meta[decoded] = 1;
399			// TODO: make a parameter from this (0 deactivates session-layer)
400			return 0;
401			}
402			}
403
404			function _saveState() {
405			global $proxy;
406			logp(get_class($this) . "->_saveState()");
407			$proxy[$this->objectId] = $this->attributes;
408			//print "_saveState: " . dumpVar($this->attributes);
409			// TODO: throw exception-message back to user if operation fails
410			}
411
412			function _loadProxy() {
413
414			// FIXME!
415			if (!$this->meta[cache][db]) { return; }
416
417			// trace & debug
418			//print Dumper($this);
419			logp(get_class($this) . "->_loadProxy()");
420
421			connectdb();
422			$sql = "SELECT payload FROM f_proxy WHERE oid='$this->objectId'";
423			if ($res = send_sql($sql)) {
424			$row = mysql_fetch_array($res, MYSQL_ASSOC);
425			if ($row) {
426			$this->payload = $row[payload];
427			// TODO: make a parameter from this (0 deactivates mysqldb-layer)
428			return 0;
429			}
430			}
431			}
432
433			// TODO: use PEAR here
434			function _saveProxy() {
435
436			// FIXME!
437			if (!$this->meta[cache][db]) { return; }
438
439			logp(get_class($this) . "->_saveProxy()");
440			connectdb();
441			if ($this->payload) {
442			//$sql = "INSERT INTO f_proxy SET payload='$this->payload' WHERE oid='$this->objectId'";
443			$sql = "INSERT INTO f_proxy SET oid='$this->objectId', payload='$this->payload'";
444			if (!send_sql($sql)) {
445			$sql = "UPDATE f_proxy SET payload='$this->payload' WHERE oid='$this->objectId'";
446			send_sql($sql);
447			}
448			}
449			}
450
451			function _loadRemote() {
452			logp(get_class($this) . "->_loadRemote()");
453
454			// trace
455			//print Dumper($this->meta);
456
457			// TODO: test backend for reachability first (eventually cache this information and "reset" it by another party)
458
459			// 1. check backend-handle
460			if (!$this->backend) {
461			logp(get_class($this) . "->_loadRemote: no backend handle, please check argument 'rpcinfo'", PEAR_LOG_CRIT);
462			return;
463			}
464
465			// determine backend action by metadata
466			// check for guid or oid
467			if ($this->meta[guid]) {
468			if (!$this->objectId) {
469			logp(get_class($this) . "->_loadRemote: argument 'guid' requires valid objectId", PEAR_LOG_WARNING);
470			return;
471			}
472			if (!$this->meta[classname]) {
473			logp(get_class($this) . "->_loadRemote: argument 'guid' requires 'classname'", PEAR_LOG_WARNING);
474			return;
475			}
476			$args = array( guid => $this->objectId, classname => $this->meta[classname] );
477			$result = $this->backend->send('getObjectByGuid', $args );
478
479			} elseif ($this->meta[oid]) {
480			if (!$this->objectId) {
481			logp(get_class($this) . "->_loadRemote: argument 'oid' requires valid objectId", PEAR_LOG_WARNING);
482			return;
483			}
484			$result = $this->backend->send('getObject', $this->objectId);
485
486			} elseif ($this->meta[key]) {
487			if (!$this->meta[command]) {
488			logp(get_class($this) . "->_loadRemote: argument 'key' requires 'command'", PEAR_LOG_WARNING);
489			return;
490			}
491			/*
492			if (!$this->meta[query]) {
493			logp(get_class($this) . "->_loadRemote: argument 'key' requires 'query'", PEAR_LOG_WARNING);
494			return;
495			}
496			*/
497			$result = $this->backend->send($this->meta[command], $this->meta[query]);
498
499			}
500
501
502
503			if ($result) {
504			//print "result: " . dumpVar($result) . "<br>";
505			if (count($result) == 0) { return; }
506
507			// FIXME: this is dangerous!
508			if ($_GET[debug]) {
509			print Dumper($result);
510			}
511
512			$this->payload = serialize($result);
513			// ----- move this to _encode some times
514
515			$this->_saveProxy();
516			//print "oid: $this->objectId<br>";
517			$this->flushState();
518			} else {
519			//print "Error in _loadRemote!!!<br>";
520			logp(get_class($this) . "->_loadRemote: error while trying to talk to remote side", PEAR_LOG_CRIT);
521			}
522
523			}
524
525			function _saveBackend($result) {
526			logp(get_class($this) . "->_saveBackend()");
527
528			//$encoder = new TextEncode($result);
529			//$encoder->toUTF8();
530
531			// check for guid or oid
532			if($this->meta[guid]) {
533			$args = array( 'guid' => $this->objectId, 'classname' => $this->meta[classname], 'data' => $result );
534			$response = $this->backend->send('saveObjectByGuid', $args, array( utf8 => 1) );
535			}
536			if($this->meta[oid]) {
537			$response = $this->backend->send('saveObject', array('oid' => $this->objectId, 'data' => $result), array( utf8 => 1) );
538			}
539			}
540
541			function _decode() {
542			// fill attributes-hashtable from message-hashtable
543			if (!$this->payload) { return; }
544			//if ($this->attributes = $backend->decodeData($this->payload)) {
545			if ($this->attributes = unserialize($this->payload)) {
546			$this->meta[decoded] = 1;
547			}
548			}
549
550			function store($struct) {
551			$this->payload = serialize($struct);
552			$this->_saveProxy();
553			}
554
555			}
556
557			?>
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