MediaFile thumbnail event hooks + VideoThumbnails plugin

The exception thrown from MediaFile will be caught and simply result in
no thumbnail at all right now. In the future we might use a catch-all
and have a "cannot generate preview"-icon or something.

VideoThumbnails requires php5-ffmpeg and php5-gd.

EVENTS.txt

@@ -1440,3 +1440,8 @@ OtherAccountProfiles: Hook to add account profiles to a user account profile blo
             href: link to the profile
             text: text for the profile
             image: mini image for the profile
+
+CreateFileImageThumbnail: Hook to create image thumbnail source from a File
+- $file:    MediaFile object with related metadata
+- &$imgPath: Path to image file which can be used as source for our thumbnail algorithm.
+- $media:   MIME media type ('image', 'video', 'audio' etc.)

classes/File.php

@@ -433,6 +433,11 @@ class File extends Managed_DataObject
         return File_thumbnail::getKV('file_id', $this->id);
     }
 
+    public function getPath()
+    {
+        return self::path($this->filename);
+    }
+
     /**
      * Blow the cache of notices that link to this URL
      *

classes/File_thumbnail.php

@@ -84,6 +84,8 @@ class File_thumbnail extends Managed_DataObject
     /**
      * Save a thumbnail record for the referenced file record.
      *
+     * FIXME: Add error handling
+     *
      * @param int $file_id
      * @param string $url
      * @param int $width

lib/imagefile.php

@@ -70,8 +70,7 @@ class ImageFile
             ($info[2] == IMAGETYPE_PNG && function_exists('imagecreatefrompng')))) {
 
             // TRANS: Exception thrown when trying to upload an unsupported image file format.
-            throw new Exception(_('Unsupported image file format.'));
+            throw new UnsupportedMediaException(_('Unsupported image format.'), $this->filepath);
-            return;
         }
 
         $this->type = ($info) ? $info[2]:$type;
@@ -79,32 +78,38 @@ class ImageFile
         $this->height = ($info) ? $info[1]:$height;
     }
 
+    public function getPath()
+    {
+        if (!file_exists($this->filepath)) {
+            throw new ServerException('No file in ImageFile filepath');
+        }
+
+        return $this->filepath;
+    }
+
     static function fromUpload($param='upload')
     {
         switch ($_FILES[$param]['error']) {
          case UPLOAD_ERR_OK: // success, jump out
             break;
+
          case UPLOAD_ERR_INI_SIZE:
          case UPLOAD_ERR_FORM_SIZE:
             // TRANS: Exception thrown when too large a file is uploaded.
             // TRANS: %s is the maximum file size, for example "500b", "10kB" or "2MB".
-            throw new Exception(sprintf(_('That file is too big. The maximum file size is %s.'),
+            throw new Exception(sprintf(_('That file is too big. The maximum file size is %s.'), ImageFile::maxFileSize()));
-                ImageFile::maxFileSize()));
+
-            return;
          case UPLOAD_ERR_PARTIAL:
             @unlink($_FILES[$param]['tmp_name']);
             // TRANS: Exception thrown when uploading an image and that action could not be completed.
             throw new Exception(_('Partial upload.'));
-            return;
+
          case UPLOAD_ERR_NO_FILE:
             // No file; probably just a non-AJAX submission.
-            return;
          default:
-            common_log(LOG_ERR, __METHOD__ . ": Unknown upload error " .
+            common_log(LOG_ERR, __METHOD__ . ": Unknown upload error " . $_FILES[$param]['error']);
-                $_FILES[$param]['error']);
             // TRANS: Exception thrown when uploading an image fails for an unknown reason.
             throw new Exception(_('System error uploading file.'));
-            return;
         }
 
         $info = @getimagesize($_FILES[$param]['tmp_name']);
@@ -112,8 +117,7 @@ class ImageFile
         if (!$info) {
             @unlink($_FILES[$param]['tmp_name']);
             // TRANS: Exception thrown when uploading a file as image that is not an image or is a corrupt file.
-            throw new Exception(_('Not an image or corrupt file.'));
+            throw new UnsupportedMediaException(_('Not an image or corrupt file.'), '[deleted]');
-            return;
         }
 
         return new ImageFile(null, $_FILES[$param]['tmp_name']);
@@ -176,7 +180,6 @@ class ImageFile
         if (!file_exists($this->filepath)) {
             // TRANS: Exception thrown during resize when image has been registered as present, but is no longer there.
             throw new Exception(_('Lost our file.'));
-            return;
         }
 
         // Don't crop/scale if it isn't necessary
@@ -214,7 +217,6 @@ class ImageFile
          default:
             // TRANS: Exception thrown when trying to resize an unknown file type.
             throw new Exception(_('Unknown file type'));
-            return;
         }
 
         $image_dest = imagecreatetruecolor($width, $height);
@@ -255,7 +257,6 @@ class ImageFile
          default:
             // TRANS: Exception thrown when trying resize an unknown file type.
             throw new Exception(_('Unknown file type'));
-            return;
         }
 
         imagedestroy($image_src);

lib/mediafile.php

@@ -43,6 +43,7 @@ class MediaFile
     var $fileurl       = null;
     var $short_fileurl = null;
     var $mimetype      = null;
+    var $thumbnailRecord = null;
 
     function __construct(Profile $scoped, $filename = null, $mimetype = null)
     {
@@ -51,7 +52,12 @@ class MediaFile
         $this->filename   = $filename;
         $this->mimetype   = $mimetype;
         $this->fileRecord = $this->storeFile();
-        $this->thumbnailRecord = $this->storeThumbnail();
+        try {
+            $this->thumbnailRecord = $this->storeThumbnail();
+        } catch (UnsupportedMediaException $e) {
+            // FIXME: Add "unknown media" icon or something
+            $this->thumbnailRecord = null;
+        }
 
         $this->fileurl = common_local_url('attachment',
                                     array('attachment' => $this->fileRecord->id));
@@ -68,6 +74,11 @@ class MediaFile
                              common_local_url('file', array('notice' => $notice->id)));
     }
 
+    public function getPath()
+    {
+        return File::path($this->filename);
+    }
+
     function shortUrl()
     {
         return $this->short_fileurl;
@@ -108,16 +119,30 @@ class MediaFile
      */
     function storeThumbnail()
     {
-        if (substr($this->mimetype, 0, strlen('image/')) != 'image/') {
+        $imgPath = null;
-            // @fixme video thumbs would be nice!
+        $media = common_get_mime_media($this->mimetype);
-            return null;
+
+        if (Event::handle('CreateFileImageThumbnail', array($this, &$imgPath, $media))) {
+            switch ($media) {
+            case 'image':
+                $imgPath = $this->getPath();
+                break;
+            default: 
+                throw new UnsupportedMediaException(_('Unsupported media format.'), $this->getPath());
+            }
         }
+        if (!file_exists($imgPath)) {
+            throw new ServerException(sprintf('Thumbnail source is not stored locally: %s', $imgPath));
+        }
+
         try {
-            $image = new ImageFile($this->fileRecord->id,
+            $image = new ImageFile($this->fileRecord->id, $imgPath);
-                                   File::path($this->filename));
+        } catch (UnsupportedMediaException $e) {
-        } catch (Exception $e) {
+            // Avoid deleting the original
-            // Unsupported image type.
+            if ($image->getPath() != $this->getPath()) {
-            return null;
+                $image->unlink();
+            }
+            throw $e;
         }
 
         $outname = File::filename($this->scoped, 'thumb-' . $this->filename, $this->mimetype);
@@ -128,7 +153,12 @@ class MediaFile
         list($width, $height) = $this->scaleToFit($image->width, $image->height, $maxWidth, $maxHeight);
 
         $image->resizeTo($outpath, $width, $height);
-        File_thumbnail::saveThumbnail($this->fileRecord->id,
+
+        // Avoid deleting the original
+        if ($image->getPath() != $this->getPath()) {
+            $image->unlink();
+        }
+        return File_thumbnail::saveThumbnail($this->fileRecord->id,
                                       File::url($outname),
                                       $width,
                                       $height);
@@ -189,40 +219,33 @@ class MediaFile
             // TRANS: Client exception thrown when an uploaded file is larger than set in php.ini.
             throw new ClientException(_('The uploaded file exceeds the ' .
                 'upload_max_filesize directive in php.ini.'));
-            return;
         case UPLOAD_ERR_FORM_SIZE:
             throw new ClientException(
                 // TRANS: Client exception.
                 _('The uploaded file exceeds the MAX_FILE_SIZE directive' .
                 ' that was specified in the HTML form.'));
-            return;
         case UPLOAD_ERR_PARTIAL:
             @unlink($_FILES[$param]['tmp_name']);
             // TRANS: Client exception.
             throw new ClientException(_('The uploaded file was only' .
                 ' partially uploaded.'));
-            return;
         case UPLOAD_ERR_NO_FILE:
             // No file; probably just a non-AJAX submission.
             return;
         case UPLOAD_ERR_NO_TMP_DIR:
             // TRANS: Client exception thrown when a temporary folder is not present to store a file upload.
             throw new ClientException(_('Missing a temporary folder.'));
-            return;
         case UPLOAD_ERR_CANT_WRITE:
             // TRANS: Client exception thrown when writing to disk is not possible during a file upload operation.
             throw new ClientException(_('Failed to write file to disk.'));
-            return;
         case UPLOAD_ERR_EXTENSION:
             // TRANS: Client exception thrown when a file upload operation has been stopped by an extension.
             throw new ClientException(_('File upload stopped by extension.'));
-            return;
         default:
             common_log(LOG_ERR, __METHOD__ . ": Unknown upload error " .
                 $_FILES[$param]['error']);
             // TRANS: Client exception thrown when a file upload operation has failed with an unknown reason.
             throw new ClientException(_('System error uploading file.'));
-            return;
         }
 
         // Throws exception if additional size does not respect quota

lib/unsupportedmediaexception.php

@@ -0,0 +1,39 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * class for an exception when a File is of unsupported media type
+ *
+ * PHP version 5
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Exception
+ * @package   GNUsocial
+ * @author    Mikael Nordfeldth <mmn@hethane.se>
+ * @copyright 2014 Free Software Foundation, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
+ * @link      https://www.gnu.org/software/social/
+ */
+
+if (!defined('GNUSOCIAL')) { exit(1); }
+
+class UnsupportedMediaException extends ServerException
+{
+    public function __construct($msg, $path)
+    {
+        common_debug(sprintf('UnsupportedMediaException "%1$s" for file "%2$s"', $msg, $path));
+        parent::__construct($msg);
+    }
+}

plugins/VideoThumbnails/VideoThumbnailsPlugin.php

@@ -0,0 +1,90 @@
+<?php
+/**
+ * GNU social - a federating social network
+ *
+ * Plugin to make thumbnails of video files with ffmpeg
+ *
+ * PHP version 5
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Plugin
+ * @package   GNUsocial
+ * @author    Mikael Nordfeldth <mmn@hethane.se>
+ * @copyright 2014 Free Software Foundation http://fsf.org
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      https://www.gnu.org/software/social/
+ */
+
+if (!defined('GNUSOCIAL')) { exit(1); }
+
+/*
+ * Dependencies:
+ *  php5-ffmpeg
+ *  php5-gd
+ *
+ * Video support will depend on your ffmpeg.
+ */
+
+class VideoThumbnailsPlugin extends Plugin
+{
+    /*
+     * This function should only extract an image from the video stream
+     * and disregard any scaling aspects in the resulting file, since
+     * this will be handled in the core thumbnail algorithm.
+     */
+    public function onCreateFileImageThumbnail(MediaFile $file, &$imgPath, $media=null)
+    {
+        // This might accidentally pass application/ogg videos.
+        // If that's a problem, let's fix it in the calling function.
+        if ($media !== 'video') {
+            return true;
+        }
+
+        $movie = new ffmpeg_movie($file->getPath(), false);
+
+        $frames = $movie->getFrameCount();
+        if ($frames > 0) {
+            $frame = $movie->getFrame(floor($frames/2));
+        } else {
+            $frame = $movie->getNextKeyFrame();
+        }
+
+        // We failed to get a frame.
+        if ($frame === null) {
+            return true;
+        }
+
+        // Let's save our frame to a temporary file. If we fail, remove it.
+        $imgPath = tempnam(sys_get_temp_dir(), 'socialthumb');
+        if (!imagejpeg($frame->toGDImage(), $imgPath)) {
+            @unlink($imgPath);
+            return true;
+        }
+        return false;
+    }
+
+    public function onPluginVersion(&$versions)
+    {
+        $versions[] = array('name' => 'Video Thumbnails',
+                            'version' => GNUSOCIAL_VERSION,
+                            'author' => 'Mikael Nordfeldth',
+                            'homepage' => 'https://www.gnu.org/software/social/',
+                            'rawdescription' =>
+                            // TRANS: Plugin description.
+                            _m('HTML5 media attachment support'));
+        return true;
+    }
+}
+