Extract GPS data from EXIF

Signed-off-by: Louis Chemineau <louis@chmn.me>
nextcloud · Oct 20, 2022 · f5d5f01 · f5d5f01
1 parent 5437573
commit f5d5f01
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Showing 2 changed files with 138 additions and 14 deletions.
diff --git a/lib/private/Metadata/FileMetadataMapper.php b/lib/private/Metadata/FileMetadataMapper.php
@@ -3,6 +3,7 @@
 declare(strict_types=1);
 /**
  * @copyright Copyright 2022 Carl Schwan <carl@carlschwan.eu>
+ * @copyright Copyright 2022 Louis Chmn <louis@chmn.me>
  * @license AGPL-3.0-or-later
  *
  * This code is free software: you can redistribute it and/or modify
@@ -24,6 +25,7 @@
 use OCP\AppFramework\Db\DoesNotExistException;
 use OCP\AppFramework\Db\MultipleObjectsReturnedException;
 use OCP\AppFramework\Db\QBMapper;
+use OCP\AppFramework\Db\Entity;
 use OCP\DB\Exception;
 use OCP\DB\QueryBuilder\IQueryBuilder;
 use OCP\IDBConnection;
@@ -102,4 +104,68 @@ public function clear(int $fileId): void {
 
 		$qb->executeStatement();
 	}
+
+	/**
+	 * Updates an entry in the db from an entity
+	 *
+	 * @param Entity $entity the entity that should be created
+	 * @return Entity the saved entity with the set id
+	 * @throws Exception
+	 * @throws \InvalidArgumentException if entity has no id
+	 * @since 14.0.0
+	 */
+	public function update(Entity $entity): Entity {
+		// if entity wasn't changed it makes no sense to run a db query
+		$properties = $entity->getUpdatedFields();
+		if (\count($properties) === 0) {
+			return $entity;
+		}
+
+		// entity needs an id
+		$id = $entity->getId();
+		if ($id === null) {
+			throw new \InvalidArgumentException(
+				'Entity which should be updated has no id');
+		}
+
+		if (!($entity instanceof FileMetadata)) {
+			throw new \Exception("Entity should be a FileMetadata entity");
+		}
+
+		// entity needs an group_name
+		$groupName = $entity->getGroupName();
+		if ($id === null) {
+			throw new \InvalidArgumentException(
+				'Entity which should be updated has no group_name');
+		}
+
+		// get updated fields to save, fields have to be set using a setter to
+		// be saved
+		// do not update the id and group_name field
+		unset($properties['id']);
+		unset($properties['group_name']);
+
+		$qb = $this->db->getQueryBuilder();
+		$qb->update($this->tableName);
+
+		// build the fields
+		foreach ($properties as $property => $updated) {
+			$column = $entity->propertyToColumn($property);
+			$getter = 'get' . ucfirst($property);
+			$value = $entity->$getter();
+
+			$type = $this->getParameterTypeForProperty($entity, $property);
+			$qb->set($column, $qb->createNamedParameter($value, $type));
+		}
+
+		$idType = $this->getParameterTypeForProperty($entity, 'id');
+		$groupNameType = $this->getParameterTypeForProperty($entity, 'groupName');
+
+		$qb->where($qb->expr()->eq('id', $qb->createNamedParameter($id, $idType)))
+		   ->andWhere($qb->expr()->eq('group_name', $qb->createNamedParameter($groupName, $groupNameType)));
+
+		$qb->executeStatement();
+
+		return $entity;
+	}
 }
diff --git a/lib/private/Metadata/Provider/ExifProvider.php b/lib/private/Metadata/Provider/ExifProvider.php
@@ -5,19 +5,41 @@
 use OC\Metadata\FileMetadata;
 use OC\Metadata\IMetadataProvider;
 use OCP\Files\File;
+use Psr\Log\LoggerInterface;
 
 class ExifProvider implements IMetadataProvider {
+	private LoggerInterface $logger;
+
+	public function __construct(
+		LoggerInterface $logger
+	) {
+		$this->logger = $logger;
+	}
+
 	public static function groupsProvided(): array {
-		return ['size'];
+		return ['size', 'gps'];
 	}
 
 	public static function isAvailable(): bool {
 		return extension_loaded('exif');
 	}
 
 	public function execute(File $file): array {
+		$exifData = [];
 		$fileDescriptor = $file->fopen('rb');
-		$data = exif_read_data($fileDescriptor, 'COMPUTED', true);
+
+		$data = null;
+		try {
+			// Needed to make reading exif data reliable.
+			// This is to trigger this condition: https://github.com/php/php-src/blob/d64aa6f646a7b5e58359dc79479860164239580a/main/streams/streams.c#L710
+			// But I don't understand why 1 as a special meaning.
+			// Revert right after reading the exif data.
+			$oldBufferSize = stream_set_chunk_size($fileDescriptor, 1);
+			$data = exif_read_data($fileDescriptor, 'ANY_TAG', true);
+			stream_set_chunk_size($fileDescriptor, $oldBufferSize);
+		} catch (\Exception $ex) {
+			$this->logger->warning("Couldn't extract metadata for ".$file->getId(), ['exception' => $ex]);
+		}
 
 		$size = new FileMetadata();
 		$size->setGroupName('size');
@@ -31,29 +53,65 @@ public function execute(File $file): array {
 					'width' => $sizeResult[0],
 					'height' => $sizeResult[1],
 				]);
+
+				$exifData['size'] = $size;
 			}
+		} elseif (array_key_exists('COMPUTED', $data)) {
+			if (array_key_exists('Width', $data['COMPUTED']) && array_key_exists('Height', $data['COMPUTED'])) {
+				$size->setMetadata([
+					'width' => $data['COMPUTED']['Width'],
+					'height' => $data['COMPUTED']['Height'],
+				]);
 
-			return [
-				'size' => $size,
-			];
+				$exifData['size'] = $size;
+			}
 		}
 
-		if (array_key_exists('COMPUTED', $data)
-			&& array_key_exists('Width', $data['COMPUTED'])
-			&& array_key_exists('Height', $data['COMPUTED'])
+		if ($data && array_key_exists('GPS', $data)
+			&& array_key_exists('GPSLatitude', $data['GPS']) && array_key_exists('GPSLatitudeRef', $data['GPS'])
+			&& array_key_exists('GPSLongitude', $data['GPS']) && array_key_exists('GPSLongitudeRef', $data['GPS'])
 		) {
-			$size->setMetadata([
-				'width' => $data['COMPUTED']['Width'],
-				'height' => $data['COMPUTED']['Height'],
+			$gps = new FileMetadata();
+			$gps->setGroupName('gps');
+			$gps->setId($file->getId());
+			$gps->setMetadata([
+				'latitude' => $this->gpsDegreesToDecimal($data['GPS']['GPSLatitude'], $data['GPS']['GPSLatitudeRef']),
+				'longitude' => $this->gpsDegreesToDecimal($data['GPS']['GPSLongitude'], $data['GPS']['GPSLongitudeRef']),
 			]);
+
+			$exifData['gps'] = $gps;
 		}
 
-		return [
-			'size' => $size,
-		];
+		return $exifData;
 	}
 
 	public static function getMimetypesSupported(): string {
 		return '/image\/.*/';
 	}
+
+	/**
+	 * @param array|string $coordinates
+	 */
+	private static function gpsDegreesToDecimal($coordinates, ?string $hemisphere): float {
+		if (is_string($coordinates)) {
+			$coordinates = array_map("trim", explode(",", $coordinates));
+		}
+
+		if (count($coordinates) !== 3) {
+			throw new \Exception('Invalid coordinate format: ' . json_encode($coordinates));
+		}
+
+		[$degrees, $minutes, $seconds] = array_map(function (string $rawDegree) {
+			$parts = explode('/', $rawDegree);
+
+			if ($parts[1] === '0') {
+				return 0;
+			}
+
+			return floatval($parts[0]) / floatval($parts[1] ?? 1);
+		}, $coordinates);
+
+		$sign = ($hemisphere === 'W' || $hemisphere === 'S') ? -1 : 1;
+		return $sign * ($degrees + $minutes / 60 + $seconds / 3600);
+	}
 }