If WOL was disabled, it causes readonly mode to occur.

PHP offers no way to determine that, so sniff for the file to guess.

Additionally to fix issues with errors occurring, enabled exceptions for sqlite3 and used that to handle silently logging the error.

Author: jdarwood007

Languages/en_US/ManageSettings.php

@@ -152,7 +152,7 @@
 $txt['cache_memcached_servers'] = 'Memcache/Memcached servers';
 $txt['cache_memcached_servers_subtext'] = 'Example: 127.0.0.1:11211,127.0.0.2';
 $txt['cache_sqlite_wal'] = 'Enable SQLite3 WAL';
-$txt['cache_sqlite_wal_subtext'] = 'Read <a href="https://www.sqlite.org/wal.html">Write-Ahead Logging</a> documentation prior to using.';
+$txt['cache_sqlite_wal_subtext'] = 'Read <a href="https://www.sqlite.org/wal.html">Write-Ahead Logging</a> documentation prior to using. If you enable then disable this setting, the database will become readonly.';
 
 $txt['loadavg_warning'] = 'Please note: the settings below are to be edited with care. Setting any of them too low may render your forum <strong>unusable</strong>!';
 $txt['loadavg_enable'] = 'Enable load balancing by load averages';

Sources/Cache/APIs/Sqlite.php

@@ -18,6 +18,7 @@
 use SMF\Cache\CacheApi;
 use SMF\Cache\CacheApiInterface;
 use SMF\Config;
+use SMF\ErrorHandler;
 use SMF\Lang;
 use SMF\Utils;
 use SQLite3;
@@ -53,6 +54,12 @@ class Sqlite extends CacheApi implements CacheApiInterface
 	 */
 	private $cacheDB = null;
 
+	/**
+	 * Indicates we have logged a error.
+	 * @var bool
+	 */
+	private bool $logOnce = false;
+
 	/****************
 	 * Public methods
 	 ****************/
@@ -71,20 +78,40 @@ public function __construct()
 	public function connect(): bool
 	{
 		$database = $this->cachedir . '/' . 'SQLite3Cache.db3';
-		$this->cacheDB = new SQLite3($database);
-		$this->cacheDB->busyTimeout(1000);
 
-		// Its a WALuigi!
-		if (!empty(Config::$cache_sqlite_wal)) {
-			$this->cacheDB->exec('PRAGMA journal_mode = wal;');
+		if (!is_writable($database) || !is_writeable($this->cachedir)) {
+			return false;
 		}
 
-		if (filesize($database) == 0) {
-			$this->cacheDB->exec('CREATE TABLE cache (key text unique, value blob, ttl int);');
-			$this->cacheDB->exec('CREATE INDEX ttls ON cache(ttl);');
-		}
+		try {
+			// Did we disable WAL?  That triggers a read only mode, dump the cache.
+			if (file_exists($this->cachedir . '/' . 'SQLite3Cache.db3-wal') && empty(Config::$modSettings['cache_sqlite_wal'])) {
+				unlink($this->cachedir . '/' . 'SQLite3Cache.db3');
+			}
+
+			$this->cacheDB = new SQLite3($database);
+			$this->cacheDB->busyTimeout(1000);
+			$this->cacheDB->enableExceptions(true);
+
+			// Its a WALuigi!
+			if (!empty(Config::$cache_sqlite_wal)) {
+				$this->cacheDB->exec('PRAGMA journal_mode = wal;');
+			}
+
+			if (filesize($database) == 0) {
+				$this->cacheDB->exec('CREATE TABLE cache (key text unique, value blob, ttl int);');
+				$this->cacheDB->exec('CREATE INDEX ttls ON cache(ttl);');
+			}
+
+			return true;
+		} catch (\Exception $ex) {
+			if (!$this->logOnce) {
+				$this->logOnce = true;
+				ErrorHandler::log(self::class . ':' . $ex->getMessage());
+			}
 
-		return true;
+			return false;
+		}
 	}
 
 	/**
@@ -107,7 +134,17 @@ public function isSupported(bool $test = false): bool
 	public function getData(string $key, ?int $ttl = null): mixed
 	{
 		$query = 'SELECT value FROM cache WHERE key = \'' . $this->cacheDB->escapeString($key) . '\' AND ttl >= ' . time() . ' LIMIT 1';
-		$result = $this->cacheDB->query($query);
+
+		try {
+			$result = $this->cacheDB->query($query);
+		} catch (\Exception $ex) {
+			if (!$this->logOnce) {
+				$this->logOnce = true;
+				ErrorHandler::log(self::class . ':' . $ex->getMessage());
+			}
+
+			return null;
+		}
 
 		$value = null;
 
@@ -130,7 +167,17 @@ public function putData(string $key, mixed $value, ?int $ttl = null): mixed
 		} else {
 			$query = 'REPLACE INTO cache VALUES (\'' . $this->cacheDB->escapeString($key) . '\', \'' . $this->cacheDB->escapeString(\is_bool($value) ? \strval(\intval($value)) : $value) . '\', ' . $ttl . ');';
 		}
-		$result = $this->cacheDB->exec($query);
+
+		try {
+			$result = $this->cacheDB->exec($query);
+		} catch (\Exception $ex) {
+			if (!$this->logOnce) {
+				$this->logOnce = true;
+				ErrorHandler::log(self::class . ':' . $ex->getMessage());
+			}
+
+			return false;
+		}
 
 		return $result;
 	}
@@ -146,10 +193,19 @@ public function cleanCache(string $type = ''): bool
 			$query = 'DELETE FROM cache;';
 		}
 
-		$result = $this->cacheDB->exec($query);
+		try {
+			$result = $this->cacheDB->exec($query);
 
-		$query = 'VACUUM;';
-		$this->cacheDB->exec($query);
+			$query = 'VACUUM;';
+			$this->cacheDB->exec($query);
+		} catch (\Exception $ex) {
+			if (!$this->logOnce) {
+				$this->logOnce = true;
+				ErrorHandler::log(self::class . ':' . $ex->getMessage());
+			}
+
+			$result = false;
+		}
 
 		$this->invalidateCache();