NEW File converter API

src/Conversion/FileConversionException.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace SilverStripe\Assets\Conversion;
+
+use LogicException;
+
+/**
+ * An exception that represents a failure to convert a file in a FileConverter class.
+ */
+class FileConversionException extends LogicException
+{
+
+}

src/Conversion/FileConversionManager.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace SilverStripe\Assets\Conversion;
+
+use SilverStripe\Assets\Storage\DBFile;
+use SilverStripe\Core\Config\Configurable;
+
+class FileConversionManager
+{
+    use Configurable;
+
+    private static $converters = [];
+
+    /**
+     * Undocumented function
+     *
+     * @throws FileConversionException if the conversion failed or there were no converters available
+     */
+    public function convert(DBFile|string $from, string $toFormat, array $options = []): DBFile
+    {
+        // TODO uhhhh figure out a nicer way to organise the converters....
+        // we ideally don't want to even ask an image converter when the formats are doc and pdf, for example...
+        foreach ($converters as $converter) {
+            /** @var FileConverter $converter */
+            if ($converter->supportsConversion($from, $toFormat, $options)) {
+                return $converter->convert($from, $toFormat, $options);
+            }
+        }
+        throw new FileConversionException('No file converter available for this conversion.');
+    }
+}

src/Conversion/FileConverter.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace SilverStripe\Assets\Conversion;
+
+use SilverStripe\Assets\Storage\DBFile;
+
+interface FileConverter
+{
+    /**
+     * Checks whether this converter supports a conversion from one file type to another.
+     *
+     * @param DBFile|string $from A DBFile instance or specific file extension
+     * @param array $options Any options defined for this converter which should apply to the conversion
+     */
+    public function supportsConversion(DBFile|string $from, string $toFormat, array $options = []): bool;
+
+    /**
+     * Converts the given DBFile instance to another file type.
+     *
+     * @param array $options Any options defined for this converter which should apply to the conversion
+     * @throws FileConversionException if invalid options are passed, or the conversion is not supported or fails
+     */
+    public function convert(DBFile $original, string $toFormat, array $options = []): DBFile;
+}

src/Conversion/InterventionImageConverter.php

@@ -0,0 +1,198 @@
+<?php
+
+namespace SilverStripe\Assets\Conversion;
+
+use Intervention\Image\Exception\ImageException;
+use SilverStripe\Assets\Image_Backend;
+use SilverStripe\Assets\InterventionBackend;
+use SilverStripe\Assets\Storage\AssetStore;
+use SilverStripe\Assets\Storage\DBFile;
+use SilverStripe\Core\Injector\Injector;
+
+/**
+ * Image converter powered by the Intervention Image library, assuming you haven't swapped out the ImageBackend implementation.
+ */
+class InterventionImageConverter implements FileConverter
+{
+    public function supportsConversion(DBFile|string $from, string $toFormat, array $options = []): bool
+    {
+        $unsupportedOptions = $this->validateOptions($options);
+        if (!empty($unsupportedOptions)) {
+            return false;
+        }
+        // If backend is not InterventionBackend, return false
+        // GD and Imagick support different things so be dynamic between those
+        if ($from instanceof DBFile) {
+            $backend = $from->getImageBackend();
+            $from = $from->getExtension() ?: $from->getMimeType();
+        } else {
+            $backend = Injector::inst()->get(Image_Backend::class);
+        }
+        // This converter requires intervention image
+        if (!is_a($backend, InterventionBackend::class)) {
+            return false;
+        }
+        /** @var InterventionBackend $backend */
+        $driver = $backend->getImageManager()->config['driver'] ?? null;
+        return $this->supportedByIntervention($from, $toFormat, $driver);
+    }
+
+    public function convert(DBFile $original, string $toFormat, array $options = []): DBFile
+    {
+        $problems = $this->validateOptions($options);
+        if (!empty($problems)) {
+            throw new FileConversionException('Invalid options provided: ' . implode(', ', $problems));
+        }
+        $quality = $options['quality'] ?? null;
+        try {
+            $result = $original->manipulateExtension(
+                $toFormat,
+                function (AssetStore $store, string $filename, string $hash, string $variant) use ($original, $quality) {
+                    $backend = clone $original->getImageBackend();
+                    if ($quality !== null) {
+                        $backend->setQuality($quality);
+                    }
+                    $config = ['conflict' => AssetStore::CONFLICT_USE_EXISTING];
+                    $tuple = $backend->writeToStore($store, $filename, $hash, $variant, $config);
+                    return [$tuple, $backend];
+                }
+            );
+        } catch (ImageException $e) {
+            throw new FileConversionException('Failed to convert: ' . $e->getMessage(), $e->getCode(), $e);
+        }
+        if ($result === null) {
+            throw new FileConversionException('File conversion resulted in null. Check whether original file actually exists.');
+        }
+        return $result;
+    }
+
+    private function validateOptions(array $options): array
+    {
+        $problems = [];
+        foreach ($options as $key => $value) {
+            if ($key !== 'quality') {
+                $problems[] = "unexpected option '$key'";
+                continue;
+            }
+            if (!is_int($value)) {
+                $problems[] = "quality value must be an integer";
+            }
+        }
+        return $problems;
+    }
+
+    private function supportedByIntervention(string $from, string $to, string $driver): bool
+    {
+        // If the driver is somehow not GD or Imagick, we have no way to know what it might support
+        if ($driver !== 'gd' && $driver !== 'imagick') {
+            return false;
+        }
+
+        foreach ([$from, $to] as $format) {
+            // This follows the logic in intervention's AbstractEncoder::process() method
+            // and the various methods in the Encoder classes for GD and Imagick
+            switch (strtolower($format)) {
+                case 'gif':
+                case 'image/gif':
+                    // always supported
+                    break;
+                case 'png':
+                case 'image/png':
+                case 'image/x-png':
+                    // always supported
+                    break;
+                case 'jpg':
+                case 'jpeg':
+                case 'jfif':
+                case 'image/jp2':
+                case 'image/jpg':
+                case 'image/jpeg':
+                case 'image/pjpeg':
+                case 'image/jfif':
+                    // always supported
+                    break;
+                case 'tif':
+                case 'tiff':
+                case 'image/tiff':
+                case 'image/tif':
+                case 'image/x-tif':
+                case 'image/x-tiff':
+                    if ($driver === 'gd') {
+                        false;
+                    }
+                    // always supported by imagick
+                    break;
+                case 'bmp':
+                case 'ms-bmp':
+                case 'x-bitmap':
+                case 'x-bmp':
+                case 'x-ms-bmp':
+                case 'x-win-bitmap':
+                case 'x-windows-bmp':
+                case 'x-xbitmap':
+                case 'image/ms-bmp':
+                case 'image/x-bitmap':
+                case 'image/x-bmp':
+                case 'image/x-ms-bmp':
+                case 'image/x-win-bitmap':
+                case 'image/x-windows-bmp':
+                case 'image/x-xbitmap':
+                    if ($driver === 'gd' && !function_exists('imagebmp')) {
+                        return false;
+                    }
+                    // always supported by imagick
+                    break;
+                case 'ico':
+                case 'image/x-ico':
+                case 'image/x-icon':
+                case 'image/vnd.microsoft.icon':
+                    if ($driver === 'gd') {
+                        return false;
+                    }
+                    // always supported by imagick
+                    break;
+                case 'psd':
+                case 'image/vnd.adobe.photoshop':
+                    if ($driver === 'gd') {
+                        return false;
+                    }
+                    // always supported by imagick
+                    break;
+                case 'webp':
+                case 'image/webp':
+                case 'image/x-webp':
+                    if ($driver === 'gd' && !function_exists('imagewebp')) {
+                        return false;
+                    }
+                    if ($driver === 'imagick' && !\Imagick::queryFormats('WEBP')) {
+                        return false;
+                    }
+                    break;
+                case 'avif':
+                case 'image/avif':
+                    if ($driver === 'gd' && !function_exists('imageavif')) {
+                        return false;
+                    }
+                    if ($driver === 'imagick' && !\Imagick::queryFormats('AVIF')) {
+                        return false;
+                    }
+                    break;
+                case 'heic':
+                case 'image/heic':
+                case 'image/heif':
+                    if ($driver === 'gd') {
+                        return false;
+                    }
+                    if ($driver === 'imagick' && !\Imagick::queryFormats('HEIC')) {
+                        return false;
+                    }
+                    break;
+                default:
+                    // Anything else is not supported
+                    return false;
+            }
+        }
+        // If we get here both formats are in the explicit list above and are supported
+        return true;
+    }
+}

src/ImageManipulation.php

@@ -4,6 +4,7 @@
 
 use InvalidArgumentException;
 use LogicException;
+use SilverStripe\Assets\Conversion\FileConversionManager;
 use SilverStripe\Assets\FilenameParsing\AbstractFileIDHelper;
 use SilverStripe\Assets\Storage\AssetContainer;
 use SilverStripe\Assets\Storage\AssetStore;
@@ -709,6 +710,19 @@ public function ThumbnailURL($width, $height)
         return $this->getIcon();
     }
 
+    public function convert(string $toFormat): AssetContainer
+    {
+        $converter = Injector::inst()->get(FileConversionManager::class);
+        if ($this instanceof File) {
+            $from = $this->File;
+        } elseif ($this instanceof DBFile) {
+            $from = $this;
+        } else {
+            $from = pathinfo($this->getFilename(), PATHINFO_EXTENSION) ?: $this->getMimeType();
+        }
+        return $converter->convert($from, $toFormat);
+    }
+
     /**
      * Return the relative URL of an icon for the file type,
      * based on the {@link appCategory()} value.