class.ilPreview.php

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<?php
/* Copyright (c) 1998-2013 ILIAS open source, Extended GPL, see docs/LICENSE */

require_once("./Services/Preview/classes/class.ilPreviewSettings.php");
require_once("./Services/Preview/classes/class.ilFSStoragePreview.php");

class ilPreview
{
        // status values
        const RENDER_STATUS_NONE = "none";
        const RENDER_STATUS_PENDING = "pending";
        const RENDER_STATUS_CREATED = "created";
        const RENDER_STATUS_FAILED = "failed";
        
        const FILENAME_FORMAT = "preview_%02d.jpg";
        
        private $obj_id = null;
        
        private $obj_type = null;
        
        private $storage = null;
        
        private $exists = false;
        
        private $render_date = false;
        
        private $render_status = self::RENDER_STATUS_NONE;
        
        public function __construct($a_obj_id, $a_type = "") 
        {
                $this->obj_id = $a_obj_id;
                $this->obj_type = $a_type;
                
                $this->init();
        }
        
        public static function createPreview($a_obj, $a_force = false)
        {
                $preview = new ilPreview($a_obj->getId(), $a_obj->getType());
                return $preview->create($a_obj, $a_force);
        }
        
        public static function deletePreview($a_obj_id)
        {
                $preview = new ilPreview($a_obj_id);
                $preview->delete();             
        }
        
        public static function copyPreviews($a_src_id, $a_dest_id)
        {
                if (!ilPreviewSettings::isPreviewEnabled())             
                        return;
                
                // get source preview
                $src = new ilPreview($a_src_id);
                $status = $src->getRenderStatus();
                
                // created? copy the previews
                if ($status == self::RENDER_STATUS_CREATED)
                {
                        // create destination preview and set it's properties
                        $dest = new ilPreview($a_dest_id);
                        $dest->setRenderDate($src->getRenderDate());
                        $dest->setRenderStatus($src->getRenderStatus());
                        
                        // create path
                        $dest->getStorage()->create();
                        
                        // copy previews
                        ilUtil::rCopy($src->getStoragePath(), $dest->getStoragePath());         
                        
                        // save copy
                        $dest->doCreate();
                }
                else
                {
                        // all other status need no action
                        // self::RENDER_STATUS_FAILED
                        // self::RENDER_STATUS_NONE
                        // self::RENDER_STATUS_PENDING
                }       
        }
        
        public static function hasPreview($a_obj_id, $a_type = "")
        {
                if (!ilPreviewSettings::isPreviewEnabled())             
                        return false;
                
                $preview = new ilPreview($a_obj_id, $a_type);
                if ($preview->exists())
                        return true;
                
                // does not exist, enable on demand rendering if there's any renderer that supports our object
                require_once("./Services/Preview/classes/class.ilRendererFactory.php");
                $renderer = ilRendererFactory::getRenderer($preview);
                return $renderer != null;
        }
        
        public static function lookupRenderStatus($a_obj_id)
        {
                $preview = new ilPreview($a_obj_id);
                return $preview->getRenderStatus();
        }
        
        public function exists()
        {
                return $this->exists;           
        }
        
        public function create($a_obj, $a_force = false)
        {
                if (!ilPreviewSettings::isPreviewEnabled())             
                        return false;
                
                // get renderer for preview
                require_once("./Services/Preview/classes/class.ilRendererFactory.php");
                $renderer = ilRendererFactory::getRenderer($this);
                
                // no renderer available?
                if ($renderer == null)
                        return false;
                
                // exists, but still pending?
                if ($this->getRenderStatus() == self::RENDER_STATUS_PENDING)
                        return false;
                
                // not forced? check if update really needed
                if ($this->getRenderStatus() == self::RENDER_STATUS_CREATED && !$a_force)
                {
                        // check last modified against last render date
                        if ($a_obj->getLastUpdateDate() <= $this->getRenderDate())
                                return false;
                }
                
                // re-create the directory to store the previews
                $this->getStorage()->delete();
                $this->getStorage()->create();
                
                // let the renderer create the preview
                $renderer->render($this, $a_obj, true);
                
                // save to database
                $this->save();
                
                return true;
        }
        
        public function delete()
        {
                // does exist?
                if ($this->exists())
                {
                        // delete files and database entry
                        $this->getStorage()->delete();
                        $this->doDelete();
                        
                        // reset values
                        $this->exists = false;
                        $this->render_date = false;
                        $this->render_status = self::RENDER_STATUS_NONE;
                }
        }
        
        public function getImages()
        {
                $images = array();
                
                // status must be created
                $path = $this->getStoragePath();
                if ($this->getRenderStatus() == self::RENDER_STATUS_CREATED)
                {
                        // load files
                        if ($handle = @opendir($path))
                        {
                                while (false !== ($file = readdir($handle)))
                                {
                                        $filepath = $path . "/" .  $file;
                                        if (!is_file($filepath)) 
                                                continue;

                                        if ($file != '.' && $file != '..' && strpos($file, "preview_") === 0)
                                        {
                                        $image = array();
                                                $image["url"] = ilUtil::getHtmlPath($filepath);
                                        
                                                // get image size
                                                $size = @getimagesize($filepath);
                                                if ($size !== false)
                                                {
                                                        $image["width"] = $size[0];
                                                        $image["height"] = $size[1];
                                                }
                                        
                                                $images[$file] = $image;
                                        }
                                }
                                closedir($handle);
                                
                                // sort by key
                                ksort($images);
                        }
                }               
                
                return $images;
        }
        
        public function save()
        {
                if ($this->exists)
                        $this->doUpdate();
                else
                        $this->doCreate();
        }
        
        protected function doCreate()
        {
                global $ilDB;
                
                $ilDB->insert(
                        "preview_data", 
                        array(
                                "obj_id" => array("integer", $this->getObjId()),
                                "render_date" => array("timestamp", $this->getRenderDate()),
                                "render_status" => array("text", $this->getRenderStatus())
                        )
                );
                $this->exists = true;
        }
        
        protected function doRead()
        {
                global $ilDB;
                
                $set = $ilDB->queryF(
                        "SELECT * FROM preview_data WHERE obj_id=%s", 
                        array("integer"), 
                        array($this->getObjId()));
                
                while ($rec = $ilDB->fetchAssoc($set))
                {
                        $this->setRenderDate($rec["render_date"]);
                        $this->setRenderStatus($rec["render_status"]);
                        $this->exists = true;
                }
        }
        
        protected function doUpdate()
        {
                global $ilDB;
                
                $ilDB->update(
                        "preview_data", 
                        array(
                                "render_date" => array("timestamp", $this->getRenderDate()),
                                "render_status" => array("text", $this->getRenderStatus())
                        ),
                        array("obj_id" => array("integer", $this->getObjId()))
                );
        }
        
        protected function doDelete()
        {
                global $ilDB;
                
                $ilDB->manipulateF(
                    "DELETE FROM preview_data WHERE obj_id=%s",
                        array("integer"), 
                        array($this->getObjId()));              
        }
        
        public function getObjId()
        {
                return $this->obj_id;
        }
        
        public function getObjType()
        {
                // not evaluated before or specified?
                if (empty($this->obj_type))
                        $this->obj_type = ilObject::_lookupType($this->getObjId(), false);      

                return $this->obj_type;
        }
        
        public function getStoragePath()
        {
                return $this->getStorage()->getPath();
        }
        
        public function getAbsoluteStoragePath()
        {
                return ILIAS_ABSOLUTE_PATH . substr($this->getStorage()->getPath(), 1);
        }       
        
        public function getFilePathFormat()
        {
                $path = ilUtil::removeTrailingPathSeparators($this->getAbsoluteStoragePath());
                return $path . "/" . self::FILENAME_FORMAT;
        }
        
        public function getRenderDate()
        {
                return $this->render_date;
        }
        
        public function setRenderDate($a_date)
        {
                $this->render_date = $a_date;
        }
        
        public function getRenderStatus()
        {
                return $this->render_status;
        }
        
        public function setRenderStatus($a_status)
        {
                $this->render_status = $a_status;
        }
        
        public function getStorage()
        {
                if ($this->storage == null)
                        $this->storage = new ilFSStoragePreview($this->obj_id);
                
                return $this->storage;
        }
        
        private function init()
        {
                // read entry
                $this->doRead();
        }
}
?>