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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[$PluginName]."</i>";
    00098             }
    00099         }
    00100
    00101         # install or upgrade plugins if needed
    00102         foreach ($this->Plugins as $PluginName => $Plugin)
    00103         {
    00104             if ($this->PluginEnabled[$PluginName])
    00105             {
    00106                 $this->InstallPlugin($Plugin);
    00107             }
    00108         }
    00109
    00110         # check plugin dependencies
    00111         $this->CheckDependencies();
    00112
    00113         # load plugin configurations
    00114         $this->DB->Query("SELECT BaseName,Cfg FROM PluginInfo");
    00115         $Cfgs = $this->DB->FetchColumn("Cfg", "BaseName");
    00116         foreach ($this->Plugins as $PluginName => $Plugin)
    00117         {
    00118             if ($this->PluginEnabled[$PluginName])
    00119             {
    00120                 if (isset($Cfgs[$PluginName]))
    00121                 {
    00122                     $Plugin->SetAllCfg(unserialize($Cfgs[$PluginName]));
    00123                 }
    00124             }
    00125         }
    00126
    00127         # initialize each plugin
    00128         foreach ($this->Plugins as $PluginName => $Plugin)
    00129         {
    00130             if ($this->PluginEnabled[$PluginName])
    00131             {
    00132                 $ErrMsg = $Plugin->Initialize();
    00133                 if ($ErrMsg !== NULL)
    00134                 {
    00135                     $this->ErrMsgs[$PluginName][] = "Initialization failed for"
    00136                             ." plugin <b>".$PluginName."</b>: <i>".$ErrMsg."</i>";
    00137                     $this->PluginEnabled[$PluginName] = FALSE;
    00138                 }
    00139             }
    00140         }
    00141
    00142         # register any events declared by each plugin
    00143         foreach ($this->Plugins as $PluginName => $Plugin)
    00144         {
    00145             if ($this->PluginEnabled[$PluginName])
    00146             {
    00147                 $Events = $Plugin->DeclareEvents();
    00148                 if (count($Events)) {  $this->AF->RegisterEvent($Events);  }
    00149             }
    00150         }
    00151
    00152         # hook plugins to events
    00153         foreach ($this->Plugins as $PluginName => $Plugin)
    00154         {
    00155             if ($this->PluginEnabled[$PluginName])
    00156             {
    00157                 $EventsToHook = $Plugin->HookEvents();
    00158                 foreach ($EventsToHook as $EventName => $PluginMethod)
    00159                 {
    00160                     if ($this->AF->IsStaticOnlyEvent($EventName))
    00161                     {
    00162                         $Caller = new PluginCaller($PluginName, $PluginMethod);
    00163                         $Result = $this->AF->HookEvent(
    00164                                 $EventName, array($Caller, "CallPluginMethod"));
    00165                     }
    00166                     else
    00167                     {
    00168                         $Result = $this->AF->HookEvent(
    00169                                 $EventName, array($Plugin, $PluginMethod));
    00170                     }
    00171                     if ($Result === FALSE)
    00172                     {
    00173                         $this->ErrMsgs[$PluginName][] =
    00174                                 "Unable to hook requested event <i>"
    00175                                 .$EventName."</i> for plugin <b>".$PluginName."</b>";
    00176                     }
    00177                 }
    00178             }
    00179         }
    00180
    00181         # limit plugin directory list to only active plugins
    00182         foreach ($this->PluginEnabled as $PluginName => $Enabled)
    00183         {
    00184             if (isset($this->PluginDirs[$PluginName]) && !$Enabled)
    00185             {
    00186                 unset($this->PluginDirs[$PluginName]);
    00187             }
    00188         }
    00189
    00190         # add plugin directories to list to be searched for object files
    00191         $ObjDirs = array();
    00192         foreach ($this->PluginDirs as $Dir)
    00193         {
    00194             $ObjDirs[$Dir] = "";
    00195         }
    00196         $this->AF->AddObjectDirectories($ObjDirs);
    00197
    00198         # report to caller whether any problems were encountered
    00199         return count($this->ErrMsgs) ? FALSE : TRUE;
    00200     }
    00201
    00206     function GetErrorMessages()
    00207     {
    00208         return $this->ErrMsgs;
    00209     }
    00210
    00216     function GetPlugin($PluginName)
    00217     {
    00218         return isset($this->Plugins[$PluginName])
    00219                 ? $this->Plugins[$PluginName] : NULL;
    00220     }
    00221
    00226     function GetPluginAttributes()
    00227     {
    00228         $Info = array();
    00229         foreach ($this->Plugins as $PluginName => $Plugin)
    00230         {
    00231             $Info[$PluginName] = $Plugin->GetAttributes();
    00232             $Info[$PluginName]["Enabled"] =
    00233                     $this->PluginInfo[$PluginName]["Enabled"];
    00234         }
    00235         return $Info;
    00236     }
    00237
    00244     function PluginEnabled($PluginName, $NewValue = NULL)
    00245     {
    00246         if ($NewValue !== NULL)
    00247         {
    00248             $this->DB->Query("UPDATE PluginInfo"
    00249                     ." SET Enabled = ".($NewValue ? "1" : "0")
    00250                     ." WHERE BaseName = '".addslashes($PluginName)."'");
    00251             $this->PluginEnabled[$PluginName] = $NewValue;
    00252             $this->PluginInfo[$PluginName]["Enabled"] = $NewValue;
    00253         }
    00254         return $this->PluginEnabled[$PluginName];
    00255     }
    00256
    00257
    00258     # ---- PRIVATE INTERFACE -------------------------------------------------
    00259
    00260     private $Plugins = array();
    00261     private $PluginFiles = array();
    00262     private $PluginNames = array();
    00263     private $PluginDirs = array();
    00264     private $PluginInfo = array();
    00265     private $PluginEnabled = array();
    00266     private $AF;
    00267     private $DirsToSearch;
    00268     private $ErrMsgs = array();
    00269     private $DB;
    00270
    00271     private function FindPlugins($DirsToSearch)
    00272     {
    00273         # for each directory
    00274         $PluginFiles = array();
    00275         foreach ($DirsToSearch as $Dir)
    00276         {
    00277             # if directory exists
    00278             if (is_dir($Dir))
    00279             {
    00280                 # for each file in directory
    00281                 $FileNames = scandir($Dir);
    00282                 foreach ($FileNames as $FileName)
    00283                 {
    00284                     # if file looks like base plugin file
    00285                     if (preg_match("/^[a-zA-Z_][a-zA-Z0-9_]*\.php$/", $FileName))
    00286                     {
    00287                         # add file to list
    00288                         $PluginName = preg_replace("/\.php$/", "", $FileName);
    00289                         $this->PluginNames[$PluginName] = $PluginName;
    00290                         $this->PluginFiles[$PluginName] = $Dir."/".$FileName;
    00291                     }
    00292                     # else if file looks like plugin directory
    00293                     elseif (is_dir($Dir."/".$FileName)
    00294                             && preg_match("/^[a-zA-Z_][a-zA-Z0-9_]*/", $FileName))
    00295                     {
    00296                         # if there is a base plugin file in the directory
    00297                         $PossibleFile = $Dir."/".$FileName."/".$FileName.".php";
    00298                         if (file_exists($PossibleFile))
    00299                         {
    00300                             # add plugin and directory to lists
    00301                             $this->PluginNames[$FileName] = $FileName;
    00302                             $this->PluginFiles[$FileName] = $PossibleFile;
    00303                             $this->PluginDirs[$FileName] = $Dir."/".$FileName;
    00304                         }
    00305                         else
    00306                         {
    00307                             $this->ErrMsgs[$FileName][] =
    00308                                     "Expected plugin file <i>".$FileName.".php</i> not"
    00309                                     ." found in plugin subdirectory <i>"
    00310                                     .$Dir."/".$FileName."</i>";
    00311                         }
    00312                     }
    00313                 }
    00314             }
    00315         }
    00316
    00317         # return list of base plugin files to caller
    00318         return $PluginFiles;
    00319     }
    00320
    00321     private function InstallPlugin($Plugin)
    00322     {
    00323         # retrieve info about plugin from database
    00324         $PluginName = get_class($Plugin);
    00325         $this->DB->Query("SELECT * FROM PluginInfo"
    00326                 ." WHERE BaseName = '".addslashes($PluginName)."'");
    00327
    00328         # if plugin was not found in database
    00329         $Attribs = $Plugin->GetAttributes();
    00330         if ($this->DB->NumRowsSelected() == 0)
    00331         {
    00332             # add plugin to database
    00333             $this->DB->Query("INSERT INTO PluginInfo"
    00334                     ." (BaseName, Version, Installed, Enabled)"
    00335                     ." VALUES ('".addslashes($PluginName)."', "
    00336                     ." '".addslashes($Attribs["Version"])."', "
    00337                     ."0, "
    00338                     ." ".($Attribs["EnabledByDefault"] ? 1 : 0).")");
    00339
    00340             # read plugin settings back in
    00341             $this->DB->Query("SELECT * FROM PluginInfo"
    00342                  ." WHERE BaseName = '".addslashes($PluginName)."'");
    00343         }
    00344
    00345         # store plugin settings for later use
    00346         $this->PluginInfo[$PluginName] = $this->DB->FetchRow();
    00347         $this->PluginEnabled[$PluginName] = $this->PluginInfo[$PluginName]["Enabled"];
    00348
    00349         # if plugin is enabled
    00350         if ($this->PluginEnabled[$PluginName])
    00351         {
    00352             # if plugin has not been installed
    00353             if (!$this->PluginInfo[$PluginName]["Installed"])
    00354             {
    00355                 # install plugin
    00356                 $ErrMsg = $Plugin->Install();
    00357
    00358                 # if install succeeded
    00359                 if ($ErrMsg == NULL)
    00360                 {
    00361                     # mark plugin as installed
    00362                     $this->DB->Query("UPDATE PluginInfo SET Installed = 1"
    00363                             ." WHERE BaseName = '".addslashes($PluginName)."'");
    00364                 }
    00365                 else
    00366                 {
    00367                     # disable plugin
    00368                     $this->PluginEnabled[$PluginName] = FALSE;
    00369
    00370                     # record error message about installation failure
    00371                     $this->ErrMsgs[$PluginName][] = "Installation of plugin <b>"
    00372                             .$PluginName."</b> failed: <i>".$ErrMsg."</i>";;
    00373                 }
    00374             }
    00375             else
    00376             {
    00377                 # if plugin version is newer than version in database
    00378                 if (version_compare($Attribs["Version"],
    00379                         $this->PluginInfo[$PluginName]["Version"]) == 1)
    00380                 {
    00381                     # upgrade plugin
    00382                     $ErrMsg = $Plugin->Upgrade($this->PluginInfo[$PluginName]["Version"]);
    00383
    00384                     # if upgrade succeeded
    00385                     if ($ErrMsg == NULL)
    00386                     {
    00387                         # update plugin version in database
    00388                         $Attribs = $Plugin->GetAttributes();
    00389                         $this->DB->Query("UPDATE PluginInfo"
    00390                                 ." SET Version = '".addslashes($Attribs["Version"])."'"
    00391                                 ." WHERE BaseName = '".addslashes($PluginName)."'");
    00392                         $this->PluginInfo[$PluginName]["Version"] = $Attribs["Version"];
    00393                     }
    00394                     else
    00395                     {
    00396                         # disable plugin
    00397                         $this->PluginEnabled[$PluginName] = FALSE;
    00398
    00399                         # record error message about upgrade failure
    00400                         $this->ErrMsgs[$PluginName][] = "Upgrade of plugin <b>"
    00401                                 .$PluginName."</b> from version <i>"
    00402                                 .addslashes($this->PluginInfo[$PluginName]["Version"])
    00403                                 ."</i> to version <i>"
    00404                                 .addslashes($Attribs["Version"])."</i> failed: <i>"
    00405                                 .$ErrMsg."</i>";
    00406                     }
    00407                 }
    00408                 # else if plugin version is older than version in database
    00409                 elseif (version_compare($Attribs["Version"],
    00410                         $this->PluginInfo[$PluginName]["Version"]) == -1)
    00411                 {
    00412                     # disable plugin
    00413                     $this->PluginEnabled[$PluginName] = FALSE;
    00414
    00415                     # record error message about version conflict
    00416                     $this->ErrMsgs[$PluginName][] = "Plugin <b>"
    00417                             .$PluginName."</b> is older (<i>"
    00418                             .addslashes($Attribs["Version"])
    00419                             ."</i>) than previously-installed version (<i>"
    00420                             .addslashes($this->PluginInfo[$PluginName]["Version"])."</i>).";
    00421                 }
    00422             }
    00423         }
    00424     }
    00425
    00426     private function CheckDependencies()
    00427     {
    00428         # look until all enabled plugins check out okay
    00429         do
    00430         {
    00431             # start out assuming all plugins are okay
    00432             $AllOkay = TRUE;
    00433
    00434             # for each plugin
    00435             foreach ($this->Plugins as $PluginName => $Plugin)
    00436             {
    00437                 # if plugin is currently enabled
    00438                 if ($this->PluginEnabled[$PluginName])
    00439                 {
    00440                     # load plugin attributes
    00441                     if (!isset($Attribs[$PluginName]))
    00442                     {
    00443                         $Attribs[$PluginName] =
    00444                                 $this->Plugins[$PluginName]->GetAttributes();
    00445                     }
    00446
    00447                     # for each dependency for this plugin
    00448                     foreach ($Attribs[$PluginName]["Requires"]
    00449                             as $ReqName => $ReqVersion)
    00450                     {
    00451                         # handle PHP version requirements
    00452                         if ($ReqName ==  "PHP")
    00453                         {
    00454                             if (version_compare($ReqVersion, phpversion(), ">"))
    00455                             {
    00456                                 $this->ErrMsgs[$PluginName][] = "PHP version "
    00457                                     ."<i>".$ReqVersion."</i>"
    00458                                     ." required by <b>".$PluginName."</b>"
    00459                                     ." was not available.  (Current PHP version"
    00460                                     ." is <i>".phpversion()."</i>.)";
    00461                             }
    00462                         }
    00463                         # handle PHP extension requirements
    00464                         elseif (preg_match("/^PHPX_/", $ReqName))
    00465                         {
    00466                             list($Dummy, $ExtensionName) = split("_", $ReqName, 2);
    00467                             if (!extension_loaded($ExtensionName))
    00468                             {
    00469                                 $this->ErrMsgs[$PluginName][] = "PHP extension "
    00470                                     ."<i>".$ExtensionName."</i>"
    00471                                     ." required by <b>".$PluginName."</b>"
    00472                                     ." was not available.";
    00473                             }
    00474                         }
    00475                         # handle dependencies on other plugins
    00476                         else
    00477                         {
    00478                             # load plugin attributes if not already loaded
    00479                             if (isset($this->Plugins[$ReqName])
    00480                                     && !isset($Attribs[$ReqName]))
    00481                             {
    00482                                 $Attribs[$ReqName] =
    00483                                         $this->Plugins[$ReqName]->GetAttributes();
    00484                             }
    00485
    00486                             # if target plugin is not present or is disabled or is too old
    00487                             if (!isset($this->PluginEnabled[$ReqName])
    00488                                     || !$this->PluginEnabled[$ReqName]
    00489                                     || (version_compare($ReqVersion,
    00490                                             $Attribs[$ReqName]["Version"], ">")))
    00491                             {
    00492                                 # add error message and disable plugin
    00493                                 $this->ErrMsgs[$PluginName][] = "Plugin <i>"
    00494                                         .$ReqName." ".$ReqVersion."</i>"
    00495                                         ." required by <b>".$PluginName."</b>"
    00496                                         ." was not available.";
    00497                                 $this->PluginEnabled[$PluginName] = FALSE;
    00498
    00499                                 # set flag indicating plugin did not check out
    00500                                 $AllOkay = FALSE;
    00501                             }
    00502                         }
    00503                     }
    00504                 }
    00505             }
    00506         } while ($AllOkay == FALSE);
    00507     }
    00508
    00510     function FindPluginPhpFile($PageName)
    00511     {
    00512         return $this->FindPluginPageFile($PageName, "php");
    00513     }
    00517     function FindPluginHtmlFile($PageName)
    00518     {
    00519         return $this->FindPluginPageFile($PageName, "html");
    00520     }
    00523     private function FindPluginPageFile($PageName, $Suffix)
    00524     {
    00525         # set up return value assuming we will not find plugin page file
    00526         $ReturnValue["PageName"] = $PageName;
    00527
    00528         # look for plugin name and plugin page name in base page name
    00529         preg_match("/P_([A-Za-z].[A-Za-z0-9]*)_([A-Za-z0-9_-]+)/", $PageName, $Matches);
    00530
    00531         # if base page name contained name of existing plugin with its own subdirectory
    00532         if ((count($Matches) == 3) && isset($this->PluginDirs[$Matches[1]]))
    00533         {
    00534             # if PHP file with specified name exists in plugin subdirectory
    00535             $PageFile = $this->PluginDirs[$Matches[1]]."/".$Matches[2].".".$Suffix;
    00536             if (file_exists($PageFile))
    00537             {
    00538                 # set return value to contain full plugin PHP file name
    00539                 $ReturnValue["PageName"] = $PageFile;
    00540             }
    00541         }
    00542
    00543         # return array containing page name or page file name to caller
    00544         return $ReturnValue;
    00545     }
    00546
    00548     static function CfgSaveCallback($BaseName, $Cfg)
    00549     {
    00550         $DB = new Database();
    00551         $DB->Query("UPDATE PluginInfo SET Cfg = '".addslashes(serialize($Cfg))
    00552                 ."' WHERE BaseName = '".addslashes($BaseName)."'");
    00553     }
    00555 }
    00556
    00568 class PluginCaller {
    00569
    00570     function __construct($PluginName, $MethodName)
    00571     {
    00572         $this->PluginName = $PluginName;
    00573         $this->MethodName = $MethodName;
    00574     }
    00575
    00576     function CallPluginMethod()
    00577     {
    00578         $Args = func_get_args();
    00579         $Plugin = self::$Manager->GetPlugin($this->PluginName);
    00580         return call_user_func_array(array($Plugin, $this->MethodName), $Args);
    00581     }
    00582
    00583     function GetCallbackAsText()
    00584     {
    00585         return $this->PluginName."::".$this->MethodName;
    00586     }
    00587
    00588     function __sleep()
    00589     {
    00590         return array("PluginName", "MethodName");
    00591     }
    00592
    00593     static public $Manager;
    00594
    00595     private $PluginName;
    00596     private $MethodName;
    00597 }
    00600 ?>