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# PluginManager.php

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    00001 <?PHP
    00002
    00006 class PluginManager {
    00007
    00008     # ---- PUBLIC INTERFACE --------------------------------------------------
    00009
    00015     function __construct($AppFramework, $PluginDirectories)
    00016     {
    00017         # save framework and directory list for later use
    00018         $this->AF = $AppFramework;
    00019         $this->DirsToSearch = $PluginDirectories;
    00020
    00021         # get our own database handle
    00022         $this->DB = new Database();
    00023
    00024         # hook into events to load plugin PHP and HTML files
    00025         $this->AF->HookEvent("EVENT_PHP_FILE_LOAD", array($this, "FindPluginPhpFile"),
    00026                 ApplicationFramework::ORDER_LAST);
    00027         $this->AF->HookEvent("EVENT_HTML_FILE_LOAD", array($this, "FindPluginHtmlFile"),
    00028                 ApplicationFramework::ORDER_LAST);
    00029
    00030         # tell PluginCaller helper object how to get to us
    00031         PluginCaller::$Manager = $this;
    00032     }
    00033
    00038     function LoadPlugins()
    00039     {
    00040         # clear any existing errors
    00041         $this->ErrMsgs = array();
    00042
    00043         # load list of all base plugin files
    00044         $this->FindPlugins($this->DirsToSearch);
    00045
    00046         # for each plugin found
    00047         foreach ($this->PluginNames as $PluginName)
    00048         {
    00049             # bring in plugin class file
    00050             include_once($this->PluginFiles[$PluginName]);
    00051
    00052             # if plugin class was defined by file
    00053             if (class_exists($PluginName))
    00054             {
    00055                 # if plugin class is a valid descendant of base plugin class
    00056                 $Plugin = new $PluginName;
    00057                 if (is_subclass_of($Plugin, "Plugin"))
    00058                 {
    00059                     # set hooks needed for plugin to access plugin manager services
    00060                     $Plugin->SetCfgSaveCallback(array(__CLASS__, "CfgSaveCallback"));
    00061
    00062                     # register the plugin
    00063                     $this->Plugins[$PluginName] = $Plugin;
    00064                     $this->PluginEnabled[$PluginName] = TRUE;
    00065                     $this->Plugins[$PluginName]->Register();
    00066
    00067                     # check required plugin attributes
    00068                     $Attribs[$PluginName] = $this->Plugins[$PluginName]->GetAttributes();
    00069                     if (!strlen($Attribs[$PluginName]["Name"]))
    00070                     {
    00071                         $this->ErrMsgs[$PluginName][] = "Plugin <b>".$PluginName."</b>"
    00072                                 ." could not be loaded because it"
    00073                                 ." did not have a <i>Name</i> attribute set.";
    00074                         unset($this->PluginEnabled[$PluginName]);
    00075                         unset($this->Plugins[$PluginName]);
    00076                     }
    00077                     if (!strlen($Attribs[$PluginName]["Version"]))
    00078                     {
    00079                         $this->ErrMsgs[$PluginName][] = "Plugin <b>".$PluginName."</b>"
    00080                                 ." could not be loaded because it"
    00081                                 ." did not have a <i>Version</i> attribute set.";
    00082                         unset($this->PluginEnabled[$PluginName]);
    00083                         unset($this->Plugins[$PluginName]);
    00084                     }
    00085                 }
    00086                 else
    00087                 {
    00088                     $this->ErrMsgs[$PluginName][] = "Plugin <b>".$PluginName."</b>"
    00089                             ." could not be loaded because <i>".$PluginName."</i> was"
    00090                             ." not a subclass of base <i>Plugin</i> class";
    00091                 }
    00092             }
    00093             else
    00094             {
    00095                 $this->ErrMsgs[$PluginName][] = "Expected class <i>".$PluginName
    00096                         ."</i> not found in plugin file <i>"
    00097                         .$this->PluginFiles[$PluginName]."</i>";
    00098             }
    00099         }
    00100
    00101         # check plugin dependencies
    00102         $this->CheckDependencies();
    00103
    00104         # load plugin configurations
    00105         $this->DB->Query("SELECT BaseName,Cfg FROM PluginInfo");
    00106         $Cfgs = $this->DB->FetchColumn("Cfg", "BaseName");
    00107
    00108         foreach ($this->Plugins as $PluginName => $Plugin)
    00109         {
    00110             if ($this->PluginEnabled[$PluginName])
    00111             {
    00112                 # set configuration values if available
    00113                 if (isset($Cfgs[$PluginName]))
    00114                 {
    00115                     $Plugin->SetAllCfg(unserialize($Cfgs[$PluginName]));
    00116                 }
    00117
    00118                 # install or upgrade plugins if needed
    00119                 $this->InstallPlugin($Plugin);
    00120             }
    00121         }
    00122
    00123         # initialize each plugin
    00124         foreach ($this->Plugins as $PluginName => $Plugin)
    00125         {
    00126             if ($this->PluginEnabled[$PluginName])
    00127             {
    00128                 $ErrMsg = $Plugin->Initialize();
    00129                 if ($ErrMsg !== NULL)
    00130                 {
    00131                     $this->ErrMsgs[$PluginName][] = "Initialization failed for"
    00132                             ." plugin <b>".$PluginName."</b>: <i>".$ErrMsg."</i>";
    00133                     $this->PluginEnabled[$PluginName] = FALSE;
    00134                 }
    00135             }
    00136         }
    00137
    00138         # register any events declared by each plugin
    00139         foreach ($this->Plugins as $PluginName => $Plugin)
    00140         {
    00141             if ($this->PluginEnabled[$PluginName])
    00142             {
    00143                 $Events = $Plugin->DeclareEvents();
    00144                 if (count($Events)) {  $this->AF->RegisterEvent($Events);  }
    00145             }
    00146         }
    00147
    00148         # hook plugins to events
    00149         foreach ($this->Plugins as $PluginName => $Plugin)
    00150         {
    00151             if ($this->PluginEnabled[$PluginName])
    00152             {
    00153                 $EventsToHook = $Plugin->HookEvents();
    00154                 foreach ($EventsToHook as $EventName => $PluginMethod)
    00155                 {
    00156                     if ($this->AF->IsStaticOnlyEvent($EventName))
    00157                     {
    00158                         $Caller = new PluginCaller($PluginName, $PluginMethod);
    00159                         $Result = $this->AF->HookEvent(
    00160                                 $EventName, array($Caller, "CallPluginMethod"));
    00161                     }
    00162                     else
    00163                     {
    00164                         $Result = $this->AF->HookEvent(
    00165                                 $EventName, array($Plugin, $PluginMethod));
    00166                     }
    00167                     if ($Result === FALSE)
    00168                     {
    00169                         $this->ErrMsgs[$PluginName][] =
    00170                                 "Unable to hook requested event <i>"
    00171                                 .$EventName."</i> for plugin <b>".$PluginName."</b>";
    00172                     }
    00173                 }
    00174             }
    00175         }
    00176
    00177         # limit plugin directory list to only active plugins
    00178         foreach ($this->PluginEnabled as $PluginName => $Enabled)
    00179         {
    00180             if (isset($this->PluginDirs[$PluginName]) && !$Enabled)
    00181             {
    00182                 unset($this->PluginDirs[$PluginName]);
    00183             }
    00184         }
    00185
    00186         # add plugin directories to list to be searched for object files
    00187         $ObjDirs = array();
    00188         foreach ($this->PluginDirs as $Dir)
    00189         {
    00190             $ObjDirs[$Dir] = "";
    00191         }
    00192         $this->AF->AddObjectDirectories($ObjDirs);
    00193
    00194         # report to caller whether any problems were encountered
    00195         return count($this->ErrMsgs) ? FALSE : TRUE;
    00196     }
    00197
    00202     function GetErrorMessages()
    00203     {
    00204         return $this->ErrMsgs;
    00205     }
    00206
    00212     function GetPlugin($PluginName)
    00213     {
    00214         return isset($this->Plugins[$PluginName])
    00215                 ? $this->Plugins[$PluginName] : NULL;
    00216     }
    00217
    00222     function GetPluginAttributes()
    00223     {
    00224         $Info = array();
    00225         foreach ($this->Plugins as $PluginName => $Plugin)
    00226         {
    00227             $Info[$PluginName] = $Plugin->GetAttributes();
    00228             $Info[$PluginName]["Enabled"] =
    00229                     isset($this->PluginInfo[$PluginName]["Enabled"])
    00230                     ? $this->PluginInfo[$PluginName]["Enabled"] : FALSE;
    00231         }
    00232         return $Info;
    00233     }
    00234
    00241     function PluginEnabled($PluginName, $NewValue = NULL)
    00242     {
    00243         if ($NewValue !== NULL)
    00244         {
    00245             $this->DB->Query("UPDATE PluginInfo"
    00246                     ." SET Enabled = ".($NewValue ? "1" : "0")
    00247                     ." WHERE BaseName = '".addslashes($PluginName)."'");
    00248             $this->PluginEnabled[$PluginName] = $NewValue;
    00249             $this->PluginInfo[$PluginName]["Enabled"] = $NewValue;
    00250         }
    00251         return $this->PluginEnabled[$PluginName];
    00252     }
    00253
    00254
    00255     # ---- PRIVATE INTERFACE -------------------------------------------------
    00256
    00257     private $Plugins = array();
    00258     private $PluginFiles = array();
    00259     private $PluginNames = array();
    00260     private $PluginDirs = array();
    00261     private $PluginInfo = array();
    00262     private $PluginEnabled = array();
    00263     private $AF;
    00264     private $DirsToSearch;
    00265     private $ErrMsgs = array();
    00266     private $DB;
    00267
    00268     private function FindPlugins($DirsToSearch)
    00269     {
    00270         # for each directory
    00271         $PluginFiles = array();
    00272         foreach ($DirsToSearch as $Dir)
    00273         {
    00274             # if directory exists
    00275             if (is_dir($Dir))
    00276             {
    00277                 # for each file in directory
    00278                 $FileNames = scandir($Dir);
    00279                 foreach ($FileNames as $FileName)
    00280                 {
    00281                     # if file looks like base plugin file
    00282                     if (preg_match("/^[a-zA-Z_][a-zA-Z0-9_]*\.php$/", $FileName))
    00283                     {
    00284                         # add file to list
    00285                         $PluginName = preg_replace("/\.php$/", "", $FileName);
    00286                         $this->PluginNames[$PluginName] = $PluginName;
    00287                         $this->PluginFiles[$PluginName] = $Dir."/".$FileName;
    00288                     }
    00289                     # else if file looks like plugin directory
    00290                     elseif (is_dir($Dir."/".$FileName)
    00291                             && preg_match("/^[a-zA-Z_][a-zA-Z0-9_]*/", $FileName))
    00292                     {
    00293                         # if there is a base plugin file in the directory
    00294                         $PossibleFile = $Dir."/".$FileName."/".$FileName.".php";
    00295                         if (file_exists($PossibleFile))
    00296                         {
    00297                             # add plugin and directory to lists
    00298                             $this->PluginNames[$FileName] = $FileName;
    00299                             $this->PluginFiles[$FileName] = $PossibleFile;
    00300                             $this->PluginDirs[$FileName] = $Dir."/".$FileName;
    00301                         }
    00302                         else
    00303                         {
    00304                             $this->ErrMsgs[$FileName][] =
    00305                                     "Expected plugin file <i>".$FileName.".php</i> not"
    00306                                     ." found in plugin subdirectory <i>"
    00307                                     .$Dir."/".$FileName."</i>";
    00308                         }
    00309                     }
    00310                 }
    00311             }
    00312         }
    00313
    00314         # return list of base plugin files to caller
    00315         return $PluginFiles;
    00316     }
    00317
    00318     private function InstallPlugin($Plugin)
    00319     {
    00320         # cache all plugin info from database
    00321         if (count($this->PluginInfo) == 0)
    00322         {
    00323             $this->DB->Query("SELECT * FROM PluginInfo");
    00324             while ($Row = $this->DB->FetchRow())
    00325             {
    00326                 $this->PluginInfo[$Row["BaseName"]] = $Row;
    00327             }
    00328         }
    00329
    00330         # if plugin was not found in database
    00331         $PluginName = get_class($Plugin);
    00332         $Attribs = $Plugin->GetAttributes();
    00333         if (!isset($this->PluginInfo[$PluginName]))
    00334         {
    00335             # add plugin to database
    00336             $this->DB->Query("INSERT INTO PluginInfo"
    00337                     ." (BaseName, Version, Installed, Enabled)"
    00338                     ." VALUES ('".addslashes($PluginName)."', "
    00339                     ." '".addslashes($Attribs["Version"])."', "
    00340                     ."0, "
    00341                     ." ".($Attribs["EnabledByDefault"] ? 1 : 0).")");
    00342
    00343             # read plugin settings back in
    00344             $this->DB->Query("SELECT * FROM PluginInfo"
    00345                  ." WHERE BaseName = '".addslashes($PluginName)."'");
    00346             $this->PluginInfo[$PluginName] = $this->DB->FetchRow();
    00347         }
    00348
    00349         # store plugin settings for later use
    00350         $this->PluginEnabled[$PluginName] = $this->PluginInfo[$PluginName]["Enabled"];
    00351
    00352         # if plugin is enabled
    00353         if ($this->PluginEnabled[$PluginName])
    00354         {
    00355             # if plugin has not been installed
    00356             if (!$this->PluginInfo[$PluginName]["Installed"])
    00357             {
    00358                 # install plugin
    00359                 $ErrMsg = $Plugin->Install();
    00360
    00361                 # if install succeeded
    00362                 if ($ErrMsg == NULL)
    00363                 {
    00364                     # mark plugin as installed
    00365                     $this->DB->Query("UPDATE PluginInfo SET Installed = 1"
    00366                             ." WHERE BaseName = '".addslashes($PluginName)."'");
    00367                     $this->PluginInfo[$PluginName]["Installed"] = 1;
    00368                 }
    00369                 else
    00370                 {
    00371                     # disable plugin
    00372                     $this->PluginEnabled[$PluginName] = FALSE;
    00373
    00374                     # record error message about installation failure
    00375                     $this->ErrMsgs[$PluginName][] = "Installation of plugin <b>"
    00376                             .$PluginName."</b> failed: <i>".$ErrMsg."</i>";;
    00377                 }
    00378             }
    00379             else
    00380             {
    00381                 # if plugin version is newer than version in database
    00382                 if (version_compare($Attribs["Version"],
    00383                         $this->PluginInfo[$PluginName]["Version"]) == 1)
    00384                 {
    00385                     # upgrade plugin
    00386                     $ErrMsg = $Plugin->Upgrade($this->PluginInfo[$PluginName]["Version"]);
    00387
    00388                     # if upgrade succeeded
    00389                     if ($ErrMsg == NULL)
    00390                     {
    00391                         # update plugin version in database
    00392                         $Attribs = $Plugin->GetAttributes();
    00393                         $this->DB->Query("UPDATE PluginInfo"
    00394                                 ." SET Version = '".addslashes($Attribs["Version"])."'"
    00395                                 ." WHERE BaseName = '".addslashes($PluginName)."'");
    00396                         $this->PluginInfo[$PluginName]["Version"] = $Attribs["Version"];
    00397                     }
    00398                     else
    00399                     {
    00400                         # disable plugin
    00401                         $this->PluginEnabled[$PluginName] = FALSE;
    00402
    00403                         # record error message about upgrade failure
    00404                         $this->ErrMsgs[$PluginName][] = "Upgrade of plugin <b>"
    00405                                 .$PluginName."</b> from version <i>"
    00406                                 .addslashes($this->PluginInfo[$PluginName]["Version"])
    00407                                 ."</i> to version <i>"
    00408                                 .addslashes($Attribs["Version"])."</i> failed: <i>"
    00409                                 .$ErrMsg."</i>";
    00410                     }
    00411                 }
    00412                 # else if plugin version is older than version in database
    00413                 elseif (version_compare($Attribs["Version"],
    00414                         $this->PluginInfo[$PluginName]["Version"]) == -1)
    00415                 {
    00416                     # disable plugin
    00417                     $this->PluginEnabled[$PluginName] = FALSE;
    00418
    00419                     # record error message about version conflict
    00420                     $this->ErrMsgs[$PluginName][] = "Plugin <b>"
    00421                             .$PluginName."</b> is older (<i>"
    00422                             .addslashes($Attribs["Version"])
    00423                             ."</i>) than previously-installed version (<i>"
    00424                             .addslashes($this->PluginInfo[$PluginName]["Version"])."</i>).";
    00425                 }
    00426             }
    00427         }
    00428     }
    00429
    00430     private function CheckDependencies()
    00431     {
    00432         # look until all enabled plugins check out okay
    00433         do
    00434         {
    00435             # start out assuming all plugins are okay
    00436             $AllOkay = TRUE;
    00437
    00438             # for each plugin
    00439             foreach ($this->Plugins as $PluginName => $Plugin)
    00440             {
    00441                 # if plugin is currently enabled
    00442                 if ($this->PluginEnabled[$PluginName])
    00443                 {
    00444                     # load plugin attributes
    00445                     if (!isset($Attribs[$PluginName]))
    00446                     {
    00447                         $Attribs[$PluginName] =
    00448                                 $this->Plugins[$PluginName]->GetAttributes();
    00449                     }
    00450
    00451                     # for each dependency for this plugin
    00452                     foreach ($Attribs[$PluginName]["Requires"]
    00453                             as $ReqName => $ReqVersion)
    00454                     {
    00455                         # handle PHP version requirements
    00456                         if ($ReqName ==  "PHP")
    00457                         {
    00458                             if (version_compare($ReqVersion, phpversion(), ">"))
    00459                             {
    00460                                 $this->ErrMsgs[$PluginName][] = "PHP version "
    00461                                     ."<i>".$ReqVersion."</i>"
    00462                                     ." required by <b>".$PluginName."</b>"
    00463                                     ." was not available.  (Current PHP version"
    00464                                     ." is <i>".phpversion()."</i>.)";
    00465                             }
    00466                         }
    00467                         # handle PHP extension requirements
    00468                         elseif (preg_match("/^PHPX_/", $ReqName))
    00469                         {
    00470                             list($Dummy, $ExtensionName) = split("_", $ReqName, 2);
    00471                             if (!extension_loaded($ExtensionName))
    00472                             {
    00473                                 $this->ErrMsgs[$PluginName][] = "PHP extension "
    00474                                     ."<i>".$ExtensionName."</i>"
    00475                                     ." required by <b>".$PluginName."</b>"
    00476                                     ." was not available.";
    00477                             }
    00478                         }
    00479                         # handle dependencies on other plugins
    00480                         else
    00481                         {
    00482                             # load plugin attributes if not already loaded
    00483                             if (isset($this->Plugins[$ReqName])
    00484                                     && !isset($Attribs[$ReqName]))
    00485                             {
    00486                                 $Attribs[$ReqName] =
    00487                                         $this->Plugins[$ReqName]->GetAttributes();
    00488                             }
    00489
    00490                             # if target plugin is not present or is disabled or is too old
    00491                             if (!isset($this->PluginEnabled[$ReqName])
    00492                                     || !$this->PluginEnabled[$ReqName]
    00493                                     || (version_compare($ReqVersion,
    00494                                             $Attribs[$ReqName]["Version"], ">")))
    00495                             {
    00496                                 # add error message and disable plugin
    00497                                 $this->ErrMsgs[$PluginName][] = "Plugin <i>"
    00498                                         .$ReqName." ".$ReqVersion."</i>"
    00499                                         ." required by <b>".$PluginName."</b>"
    00500                                         ." was not available.";
    00501                                 $this->PluginEnabled[$PluginName] = FALSE;
    00502
    00503                                 # set flag indicating plugin did not check out
    00504                                 $AllOkay = FALSE;
    00505                             }
    00506                         }
    00507                     }
    00508                 }
    00509             }
    00510         } while ($AllOkay == FALSE);
    00511     }
    00512
    00514     function FindPluginPhpFile($PageName)
    00515     {
    00516         return $this->FindPluginPageFile($PageName, "php");
    00517     }
    00521     function FindPluginHtmlFile($PageName)
    00522     {
    00523         return $this->FindPluginPageFile($PageName, "html");
    00524     }
    00527     private function FindPluginPageFile($PageName, $Suffix)
    00528     {
    00529         # set up return value assuming we will not find plugin page file
    00530         $ReturnValue["PageName"] = $PageName;
    00531
    00532         # look for plugin name and plugin page name in base page name
    00533         preg_match("/P_([A-Za-z].[A-Za-z0-9]*)_([A-Za-z0-9_-]+)/", $PageName, $Matches);
    00534
    00535         # if base page name contained name of existing plugin with its own subdirectory
    00536         if ((count($Matches) == 3) && isset($this->PluginDirs[$Matches[1]]))
    00537         {
    00538             # if PHP file with specified name exists in plugin subdirectory
    00539             $PageFile = $this->PluginDirs[$Matches[1]]."/".$Matches[2].".".$Suffix;
    00540             if (file_exists($PageFile))
    00541             {
    00542                 # set return value to contain full plugin PHP file name
    00543                 $ReturnValue["PageName"] = $PageFile;
    00544             }
    00545         }
    00546
    00547         # return array containing page name or page file name to caller
    00548         return $ReturnValue;
    00549     }
    00550
    00552     static function CfgSaveCallback($BaseName, $Cfg)
    00553     {
    00554         $DB = new Database();
    00555         $DB->Query("UPDATE PluginInfo SET Cfg = '".addslashes(serialize($Cfg))
    00556                 ."' WHERE BaseName = '".addslashes($BaseName)."'");
    00557     }
    00559 }
    00560
    00572 class PluginCaller {
    00573
    00574     function __construct($PluginName, $MethodName)
    00575     {
    00576         $this->PluginName = $PluginName;
    00577         $this->MethodName = $MethodName;
    00578     }
    00579
    00580     function CallPluginMethod()
    00581     {
    00582         $Args = func_get_args();
    00583         $Plugin = self::$Manager->GetPlugin($this->PluginName);
    00584         return call_user_func_array(array($Plugin, $this->MethodName), $Args);
    00585     }
    00586
    00587     function GetCallbackAsText()
    00588     {
    00589         return $this->PluginName."::".$this->MethodName;
    00590     }
    00591
    00592     function __sleep()
    00593     {
    00594         return array("PluginName", "MethodName");
    00595     }
    00596
    00597     static public $Manager;
    00598
    00599     private $PluginName;
    00600     private $MethodName;
    00601 }
    00604 ?>