Allow DAV Object properties

The current implementation only saves them as string. It seems they can
be more complex than that, and that objects were saved directly.

You may find such objects saved in some production databases by
executing:
```sql
SELECT * from oc_properties where propertyvalue = 'Object';
```

This commit adds a repair job to clean all of these "broken" properties
values, adds a new database column to save the type of the property, and
handles converting from and to correct values.

Implementation is very similar to SabreDAV's own PDO backend: https://github.com/nextcloud/3rdparty/blob/4921806dfb1c5c309eac60195ed34e2749baf3c1/sabre/dav/lib/DAV/PropertyStorage/Backend/PDO.php

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

1 files changed, 58 insertions, 12 deletions

diff --git a/apps/dav/lib/DAV/CustomPropertiesBackend.php b/apps/dav/lib/DAV/CustomPropertiesBackend.php
index acee65cd00d..bd09ac2e4e6 100644
--- a/apps/dav/lib/DAV/CustomPropertiesBackend.php
+++ b/apps/dav/lib/DAV/CustomPropertiesBackend.php
@@ -31,6 +31,7 @@ use Sabre\DAV\PropertyStorage\Backend\BackendInterface;
 use Sabre\DAV\PropFind;
 use Sabre\DAV\PropPatch;
 use Sabre\DAV\Tree;
+use Sabre\DAV\Xml\Property\Complex;
 use function array_intersect;
 
 class CustomPropertiesBackend implements BackendInterface {
@@ -39,6 +40,21 @@ class CustomPropertiesBackend implements BackendInterface {
 	private const TABLE_NAME = 'properties';
 
 	/**
+	 * Value is stored as string.
+	 */
+	public const PROPERTY_TYPE_STRING = 1;
+
+	/**
+	 * Value is stored as XML fragment.
+	 */
+	public const PROPERTY_TYPE_XML = 2;
+
+	/**
+	 * Value is stored as a property object.
+	 */
+	public const PROPERTY_TYPE_OBJECT = 3;
+
+	/**
 	 * Ignored properties
 	 *
 	 * @var string[]
@@ -239,7 +255,7 @@ class CustomPropertiesBackend implements BackendInterface {
 		$result = $qb->executeQuery();
 		$props = [];
 		while ($row = $result->fetch()) {
-			$props[$row['propertyname']] = $row['propertyvalue'];
+			$props[$row['propertyname']] = $this->decodeValueFromDatabase($row['propertyvalue'], $row['valuetype']);
 		}
 		$result->closeCursor();
 		return $props;
@@ -282,7 +298,7 @@ class CustomPropertiesBackend implements BackendInterface {
 
 		$props = [];
 		while ($row = $result->fetch()) {
-			$props[$row['propertyname']] = $row['propertyvalue'];
+			$props[$row['propertyname']] = $this->decodeValueFromDatabase($row['propertyvalue'], $row['valuetype']);
 		}
 
 		$result->closeCursor();
@@ -304,9 +320,9 @@ class CustomPropertiesBackend implements BackendInterface {
 			' WHERE `userid` = ? AND `propertypath` = ? AND `propertyname` = ?';
 
 		$insertStatement = 'INSERT INTO `*PREFIX*properties`' .
-			' (`userid`,`propertypath`,`propertyname`,`propertyvalue`) VALUES(?,?,?,?)';
+			' (`userid`,`propertypath`,`propertyname`,`propertyvalue`, `valuetype`) VALUES(?,?,?,?,?)';
 
-		$updateStatement = 'UPDATE `*PREFIX*properties` SET `propertyvalue` = ?' .
+		$updateStatement = 'UPDATE `*PREFIX*properties` SET `propertyvalue` = ?, `valuetype` = ?' .
 			' WHERE `userid` = ? AND `propertypath` = ? AND `propertyname` = ?';
 
 		// TODO: use "insert or update" strategy ?
@@ -325,24 +341,22 @@ class CustomPropertiesBackend implements BackendInterface {
 					);
 				}
 			} else {
-				if ($propertyValue instanceOf \Sabre\DAV\Xml\Property\Complex) {
-					$propertyValue = $propertyValue->getXml();
-				} elseif (!is_string($propertyValue)) {
-					$propertyValue = (string)$propertyValue;
-				}
+				[$value, $valueType] = $this->encodeValueForDatabase($propertyValue);
 				if (!array_key_exists($propertyName, $existing)) {
 					$this->connection->executeUpdate($insertStatement,
 						[
 							$this->user->getUID(),
 							$this->formatPath($path),
 							$propertyName,
-							$propertyValue,
+							$value,
+							$valueType
 						]
 					);
 				} else {
 					$this->connection->executeUpdate($updateStatement,
 						[
-							$propertyValue,
+							$value,
+							$valueType,
 							$this->user->getUID(),
 							$this->formatPath($path),
 							$propertyName,
@@ -367,8 +381,40 @@ class CustomPropertiesBackend implements BackendInterface {
 	private function formatPath(string $path): string {
 		if (strlen($path) > 250) {
 			return sha1($path);
+		}
+
+		return $path;
+	}
+
+	/**
+	 * @param mixed $value
+	 * @return array
+	 */
+	private function encodeValueForDatabase($value): array {
+		if (is_scalar($value)) {
+			$valueType = self::PROPERTY_TYPE_STRING;
+		} elseif ($value instanceof Complex) {
+			$valueType = self::PROPERTY_TYPE_XML;
+			$value = $value->getXml();
 		} else {
-			return $path;
+			$valueType = self::PROPERTY_TYPE_OBJECT;
+			$value = serialize($value);
+		}
+		return [$value, $valueType];
+	}
+
+	/**
+	 * @return mixed|Complex|string
+	 */
+	private function decodeValueFromDatabase(string $value, int $valueType) {
+		switch ($valueType) {
+			case self::PROPERTY_TYPE_XML:
+				return new Complex($value);
+			case self::PROPERTY_TYPE_OBJECT:
+				return unserialize($value);
+			case self::PROPERTY_TYPE_STRING:
+			default:
+				return $value;
 		}
 	}
 }