wiki.techinc.nl/includes/utils/MWFileProps.php
Tim Starling b4849e03b7 Use the unserialized form of image metadata internally
Image metadata is usually a serialized string representing an array.
Passing the string around internally and having everything unserialize
it is an awkward convention.

Also, many image handlers were reading the file twice: once for
getMetadata() and again for getImageSize(). Often getMetadata()
would actually read the width and height and then throw it away.

So, in filerepo:

* Add File::getMetadataItem(), which promises to allow partial
  loading of metadata per my proposal on T275268 in a future commit.
* Add File::getMetadataArray(), which returns the unserialized array.
  Some file handlers were returning non-serializable strings from
  getMetadata(), so I gave them a legacy array form ['_error' => ...]
* Changed MWFileProps to return the array form of metadata.
* Deprecate the weird File::getImageSize(). It was apparently not
  called by anything, but was overridden by UnregisteredLocalFile.
* Wrap serialize/unserialize with File::getMetadataForDb() and
  File::loadMetadataFromDb() in preparation for T275268.

In MediaHandler:

* Merged MediaHandler::getImageSize() and MediaHandler::getMetadata()
  into getSizeAndMetadata(). Deprecated the old methods.
* Instead of isMetadataValid() we now have isFileMetadataValid(), which
  only gets a File object, so it can decide what data it needs to load.
* Simplified getPageDimensions() by having it return false for non-paged
  media. It was not called in that case, but was implemented anyway.

In specific handlers:

* Rename DjVuHandler::getUnserializedMetadata() and
  extractTreesFromMetadata() for clarity. "Metadata" in these function
  names meant an XML string.
* Updated DjVuImage::getImageSize() to provide image sizes in the new
  style.
* In ExifBitmapHandler, getRotationForExif() now takes just the
  Orientation tag, rather than a serialized string. Also renamed for
  clarity.
* In GIFMetadataExtractor, return the width, height and bits per channel
  instead of throwing them away. There was some conflation in
  decodeBPP() which I picked apart. Refer to GIF89a section 18.
* In JpegMetadataExtractor, process the SOF0/SOF2 segment to extract
  bits per channel, width, height and components (channel count). This
  is essentially a port of PHP's getimagesize(), so should be bugwards
  compatible.
* In PNGMetadataExtractor, return the width and height, which were
  previously assigned to unused local variables. I verified the
  implementation by referring to the specification.
* In SvgHandler, retain the version validation from unpackMetadata(),
  but rename the function since it now takes an array as input.

In tests:

* In ExifBitmapTest, refactored some tests by using a provider.
* In GIFHandlerTest and PNGHandlerTest, I removed the tests in which
  getMetadata() returns null, since it doesn't make sense when ported to
  getMetadataArray(). I added tests for empty arrays instead.
* In tests, I retained serialization of input data since I figure it's
  useful to confirm that existing database rows will continue to be read
  correctly. I removed serialization of expected values, replacing them
  with plain data.
* In tests, I replaced access to private class constants like
  BROKEN_FILE with string literals, since stability is essential. If
  the class constant changes, the test should fail.

Elsewhere:

* In maintenance/refreshImageMetadata.php, I removed the check for
  shrinking image metadata, since it's not easy to implement and is
  not future compatible. Image metadata is expected to shrink in
  future.

Bug: T275268
Change-Id: I039785d5b6439d71dcc21dcb972177dba5c3a67d
2021-06-08 17:04:01 +10:00

127 lines
3.6 KiB
PHP

<?php
/**
* MimeMagic helper functions for detecting and dealing with MIME types.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
/**
* MimeMagic helper wrapper
*
* @since 1.28
*/
class MWFileProps {
/** @var MimeAnalyzer */
private $magic;
/**
* @param MimeAnalyzer $magic
*/
public function __construct( MimeAnalyzer $magic ) {
$this->magic = $magic;
}
/**
* Get an associative array containing information about
* a file with the given storage path.
*
* Resulting array fields include:
* - fileExists
* - size (filesize in bytes)
* - mime (as major/minor)
* - media_type (value to be used with the MEDIATYPE_xxx constants)
* - metadata (handler specific)
* - sha1 (in base 36)
* - width
* - height
* - bits (bitrate)
* - file-mime
* - major_mime
* - minor_mime
*
* @param string $path Filesystem path to a file
* @param string|bool|null $ext The file extension, or true to extract it from the filename.
* Set it to false to ignore the extension. Might be null in case the file is going to be
* stashed.
* @return array
* @since 1.28
*/
public function getPropsFromPath( $path, $ext ) {
$fsFile = new FSFile( $path );
$info = $this->newPlaceholderProps();
$info['fileExists'] = $fsFile->exists();
if ( $info['fileExists'] ) {
$info['size'] = $fsFile->getSize(); // bytes
$info['sha1'] = $fsFile->getSha1Base36();
# MIME type according to file contents
$info['file-mime'] = $this->magic->guessMimeType( $path, false );
# Logical MIME type
$ext = ( $ext === true ) ? FileBackend::extensionFromPath( $path ) : (string)$ext;
# XXX: MimeAnalyzer::improveTypeFromExtension() may return null (T253483).
# Unclear if callers of this method expect that.
$info['mime'] = $this->magic->improveTypeFromExtension( $info['file-mime'], $ext );
list( $info['major_mime'], $info['minor_mime'] ) = File::splitMime( $info['mime'] );
$info['media_type'] = $this->magic->getMediaType( $path, $info['mime'] );
# Height, width and metadata
$handler = MediaHandler::getHandler( $info['mime'] );
if ( $handler ) {
$sizeAndMetadata = $handler->getSizeAndMetadataWithFallback( $fsFile, $path );
if ( $sizeAndMetadata ) {
$info = $sizeAndMetadata + $info;
}
}
}
return $info;
}
/**
* Empty place holder props for non-existing files
*
* Resulting array fields include:
* - fileExists
* - size (filesize in bytes)
* - mime (as major/minor)
* - media_type (value to be used with the MEDIATYPE_xxx constants)
* - metadata (handler specific)
* - sha1 (in base 36)
* - width
* - height
* - bits (bitrate)
* - file-mime
* - major_mime
* - minor_mime
*
* @return array
* @since 1.28
*/
public function newPlaceholderProps() {
return FSFile::placeholderProps() + [
'metadata' => [],
'width' => 0,
'height' => 0,
'bits' => 0,
'media_type' => MEDIATYPE_UNKNOWN
];
}
}