app/Uploads/ImageResizer.php
<?php
namespace BookStack\Uploads;
use BookStack\Exceptions\ImageUploadException;
use Exception;
use GuzzleHttp\Psr7\Utils;
use Illuminate\Support\Facades\Cache;
use Intervention\Image\Decoders\BinaryImageDecoder;
use Intervention\Image\Drivers\Gd\Decoders\NativeObjectDecoder;
use Intervention\Image\Drivers\Gd\Driver;
use Intervention\Image\Encoders\AutoEncoder;
use Intervention\Image\Encoders\PngEncoder;
use Intervention\Image\Interfaces\ImageInterface as InterventionImage;
use Intervention\Image\ImageManager;
use Intervention\Image\Origin;
class ImageResizer
{
protected const THUMBNAIL_CACHE_TIME = 604_800; // 1 week
public function __construct(
protected ImageStorage $storage,
) {
}
/**
* Load gallery thumbnails for a set of images.
* @param iterable<Image> $images
*/
public function loadGalleryThumbnailsForMany(iterable $images, bool $shouldCreate = false): void
{
foreach ($images as $image) {
$this->loadGalleryThumbnailsForImage($image, $shouldCreate);
}
}
/**
* Load gallery thumbnails into the given image instance.
*/
public function loadGalleryThumbnailsForImage(Image $image, bool $shouldCreate): void
{
$thumbs = ['gallery' => null, 'display' => null];
try {
$thumbs['gallery'] = $this->resizeToThumbnailUrl($image, 150, 150, false, $shouldCreate);
$thumbs['display'] = $this->resizeToThumbnailUrl($image, 1680, null, true, $shouldCreate);
} catch (Exception $exception) {
// Prevent thumbnail errors from stopping execution
}
$image->setAttribute('thumbs', $thumbs);
}
/**
* Get the thumbnail for an image.
* If $keepRatio is true only the width will be used.
* Checks the cache then storage to avoid creating / accessing the filesystem on every check.
*
* @throws Exception
*/
public function resizeToThumbnailUrl(
Image $image,
?int $width,
?int $height,
bool $keepRatio = false,
bool $shouldCreate = false
): ?string {
// Do not resize GIF images where we're not cropping
if ($keepRatio && $this->isGif($image)) {
return $this->storage->getPublicUrl($image->path);
}
$thumbDirName = '/' . ($keepRatio ? 'scaled-' : 'thumbs-') . $width . '-' . $height . '/';
$imagePath = $image->path;
$thumbFilePath = dirname($imagePath) . $thumbDirName . basename($imagePath);
$thumbCacheKey = 'images::' . $image->id . '::' . $thumbFilePath;
// Return path if in cache
$cachedThumbPath = Cache::get($thumbCacheKey);
if ($cachedThumbPath && !$shouldCreate) {
return $this->storage->getPublicUrl($cachedThumbPath);
}
// If thumbnail has already been generated, serve that and cache path
$disk = $this->storage->getDisk($image->type);
if (!$shouldCreate && $disk->exists($thumbFilePath)) {
Cache::put($thumbCacheKey, $thumbFilePath, static::THUMBNAIL_CACHE_TIME);
return $this->storage->getPublicUrl($thumbFilePath);
}
$imageData = $disk->get($imagePath);
// Do not resize apng images where we're not cropping
if ($keepRatio && $this->isApngData($image, $imageData)) {
Cache::put($thumbCacheKey, $image->path, static::THUMBNAIL_CACHE_TIME);
return $this->storage->getPublicUrl($image->path);
}
// If not in cache and thumbnail does not exist, generate thumb and cache path
$thumbData = $this->resizeImageData($imageData, $width, $height, $keepRatio, $this->getExtension($image));
$disk->put($thumbFilePath, $thumbData, true);
Cache::put($thumbCacheKey, $thumbFilePath, static::THUMBNAIL_CACHE_TIME);
return $this->storage->getPublicUrl($thumbFilePath);
}
/**
* Resize the image of given data to the specified size, and return the new image data.
* Format will remain the same as the input format, unless specified.
*
* @throws ImageUploadException
*/
public function resizeImageData(
string $imageData,
?int $width,
?int $height,
bool $keepRatio,
?string $format = null,
): string {
try {
$thumb = $this->interventionFromImageData($imageData, $format);
} catch (Exception $e) {
throw new ImageUploadException(trans('errors.cannot_create_thumbs'));
}
$this->orientImageToOriginalExif($thumb, $imageData);
if ($keepRatio) {
$thumb->scaleDown($width, $height);
} else {
$thumb->cover($width, $height);
}
$encoder = match ($format) {
'png' => new PngEncoder(),
default => new AutoEncoder(),
};
$thumbData = (string) $thumb->encode($encoder);
// Use original image data if we're keeping the ratio
// and the resizing does not save any space.
if ($keepRatio && strlen($thumbData) > strlen($imageData)) {
return $imageData;
}
return $thumbData;
}
/**
* Create an intervention image instance from the given image data.
* Performs some manual library usage to ensure image is specifically loaded
* from given binary data instead of data being misinterpreted.
*/
protected function interventionFromImageData(string $imageData, ?string $fileType): InterventionImage
{
$manager = new ImageManager(new Driver());
// Ensure gif images are decoded natively instead of deferring to intervention GIF
// handling since we don't need the added animation support.
$isGif = $fileType === 'gif';
$decoder = $isGif ? NativeObjectDecoder::class : BinaryImageDecoder::class;
$input = $isGif ? @imagecreatefromstring($imageData) : $imageData;
$image = $manager->read($input, $decoder);
if ($isGif) {
$image->setOrigin(new Origin('image/gif'));
}
return $image;
}
/**
* Orientate the given intervention image based upon the given original image data.
* Intervention does have an `orientate` method but the exif data it needs is lost before it
* can be used (At least when created using binary string data) so we need to do some
* implementation on our side to use the original image data.
* Bulk of logic taken from: https://github.com/Intervention/image/blob/b734a4988b2148e7d10364b0609978a88d277536/src/Intervention/Image/Commands/OrientateCommand.php
* Copyright (c) Oliver Vogel, MIT License.
*/
protected function orientImageToOriginalExif(InterventionImage $image, string $originalData): void
{
if (!extension_loaded('exif')) {
return;
}
$stream = Utils::streamFor($originalData)->detach();
$exif = @exif_read_data($stream);
$orientation = $exif ? ($exif['Orientation'] ?? null) : null;
switch ($orientation) {
case 2:
$image->flip();
break;
case 3:
$image->rotate(180);
break;
case 4:
$image->rotate(180)->flip();
break;
case 5:
$image->rotate(270)->flip();
break;
case 6:
$image->rotate(270);
break;
case 7:
$image->rotate(90)->flip();
break;
case 8:
$image->rotate(90);
break;
}
}
/**
* Checks if the image is a gif. Returns true if it is, else false.
*/
protected function isGif(Image $image): bool
{
return $this->getExtension($image) === 'gif';
}
/**
* Get the extension for the given image, normalised to lower-case.
*/
protected function getExtension(Image $image): string
{
return strtolower(pathinfo($image->path, PATHINFO_EXTENSION));
}
/**
* Check if the given image and image data is apng.
*/
protected function isApngData(Image $image, string &$imageData): bool
{
$isPng = strtolower(pathinfo($image->path, PATHINFO_EXTENSION)) === 'png';
if (!$isPng) {
return false;
}
$initialHeader = substr($imageData, 0, strpos($imageData, 'IDAT'));
return str_contains($initialHeader, 'acTL');
}
}