nextcloud-server/lib/public/IPreview.php

<?php

/**
 * SPDX-FileCopyrightText: 2016-2024 Nextcloud GmbH and Nextcloud contributors
 * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
 * SPDX-License-Identifier: AGPL-3.0-only
 */

namespace OCP;

use Closure;
use OCP\AppFramework\Attribute\Consumable;
use OCP\Files\File;
use OCP\Files\FileInfo;
use OCP\Files\NotFoundException;
use OCP\Files\SimpleFS\ISimpleFile;
use OCP\Preview\IProviderV2;

/**
 * Public interface for discovering preview providers and generating file previews.
 *
 * ProviderClosure lazily resolves a preview provider and may return false if it
 * cannot be loaded.
 *
 * @since 6.0.0
 * @psalm-type ProviderClosure = Closure():(IProviderV2|false)
 */
#[Consumable(since: '6.0.0')]
interface IPreview {
	/**
	 * Preview scaling mode that fills the requested dimensions.
	 *
	 * @since 11.0.0
	 */
	public const MODE_FILL = 'fill';

	/**
	 * Preview scaling mode that covers the requested dimensions.
	 *
	 * @since 11.0.0
	 */
	public const MODE_COVER = 'cover';

	/**
	 * Returns the registered preview providers grouped by supported mime-type regex.
	 *
	 * Each value is a list of closures that create preview providers when invoked,
	 * not a list of already instantiated provider objects.
	 *
	 * The provider list is built on demand and is empty when previews are disabled.
	 *
	 * @return array<string, list<ProviderClosure>> Map of mime-type regex to provider-creating closures
	 * @since 8.1.0
	 */
	public function getProviders(): array;

	/**
	 * Does the manager have any providers
	 * @since 8.1.0
	 */
	public function hasProviders(): bool;

	/**
	 * Returns a preview of a file
	 *
	 * The cache is searched first and if nothing usable was found then a preview is
	 * generated by one of the providers
	 *
	 * @param IPreview::MODE_* $mode
	 * @param string $mimeType To force a given mimetype for the file (files_versions needs this)
	 * @param bool $cacheResult Whether to cache the preview on the filesystem. Default to true. Can be useful to set to false to limit the amount of stored previews.
	 * @return ISimpleFile
	 * @throws NotFoundException
	 * @throws \InvalidArgumentException if the preview would be invalid (in case the original image is invalid)
	 * @since 11.0.0 - \InvalidArgumentException was added in 12.0.0
	 * @since 32.0.0 - getPreview($cacheResult) added the $cacheResult argument to the signature
	 */
	public function getPreview(File $file, int $width = -1, int $height = -1, bool $crop = false, string $mode = IPreview::MODE_FILL, ?string $mimeType = null, bool $cacheResult = true): ISimpleFile;

	/**
	 * Returns whether any registered preview provider supports the given mime type.
	 *
	 * This checks the mime type against the providers' registered mime-type regexes.
	 * It does not guarantee that preview generation will succeed for a specific file.
	 *
	 * @param string $mimeType Mime type string to test, for example "image/png"
	 * @since 6.0.0
	 */
	public function isMimeSupported(string $mimeType = '*'): bool;

	/**
	 * Returns whether a preview can currently be generated for the given file.
	 *
	 * This checks whether the effective mime type is supported, whether previews
	 * are allowed on the file's mount, and whether at least one matching provider is
	 * available for the file in the current environment.
	 *
	 * @param FileInfo $file
	 * @param string|null $mimeType Optional mime type override to use instead of $file->getMimeType()
	 * @since 8.0.0
	 * @since 32.0.0 - isAvailable($mimeType) added the $mimeType argument to the signature
	 */
	public function isAvailable(FileInfo $file, ?string $mimeType = null): bool;

	/**
	 * Generates previews of a file
	 *
	 * @param array $specifications
	 * @return ISimpleFile the last preview that was generated
	 * @throws NotFoundException
	 * @throws \InvalidArgumentException if the preview would be invalid (in case the original image is invalid)
	 * @since 19.0.0
	 */
	public function generatePreviews(File $file, array $specifications, ?string $mimeType = null): ISimpleFile;
}