PluginManager.php

Go to the documentation of this file.
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 ?>