🔒DB lock v0.3 #685 + cleanup

front/php/server/db.php

@@ -58,37 +58,83 @@ function SQLite3_connect ($trytoreconnect, $retryCount = 0) {
 }
 
 
+//------------------------------------------------------------------------------
+// ->query override to handle retries 
+//------------------------------------------------------------------------------
+class CustomDatabaseWrapper {
+  private $sqlite;
+  private $maxRetries;
+  private $retryDelay;
+  
+
+  public function __construct($filename, $flags = SQLITE3_OPEN_READWRITE | SQLITE3_OPEN_CREATE, $maxRetries = 3, $retryDelay = 1000, $encryptionKey = null) {
+      $this->sqlite = new SQLite3($filename, $flags, $encryptionKey);
+
+      $this->maxRetries = $maxRetries;
+      $this->retryDelay = $retryDelay;
+  }
+
+  public function query(string $query): SQLite3Result|bool {
+      global $DBFILE_LOCKED_FILE;
+
+      $attempts = 0;
+      while ($attempts < $this->maxRetries) {
+          $result = $this->sqlite->query($query);
+          if ($result !== false) {
+              // Write unlock status to the locked file
+              file_put_contents($DBFILE_LOCKED_FILE, '0');
+              return $result;
+          }
+
+          // Write lock status to the locked file
+          file_put_contents($DBFILE_LOCKED_FILE, '1');
+
+          $attempts++;
+          usleep($this->retryDelay * 1000); // Retry delay in milliseconds
+      }
+
+      // If all retries failed, throw an exception or handle the error as needed
+      echo '<script>alert("Error executing query (attempts: ' . $attempts . '"), query: '.$query.'</script>';
+      throw new Exception("Query failed after {$this->maxRetries} attempts: " . $this->sqlite->lastErrorMsg());
+  }
+
+  // Delegate other SQLite3 methods to the $sqlite instance
+  public function __call($name, $arguments) {
+      return call_user_func_array([$this->sqlite, $name], $arguments);
+  }
+}
+
+
 //------------------------------------------------------------------------------
 // Open DB
 //------------------------------------------------------------------------------
 
-function OpenDB (...$DBPath) {
+function OpenDB($DBPath = null) {
   global $DBFILE;
   global $db;
 
-  // use custom path if supplied
-  foreach ($DBPath as $path) {  
-    $DBFILE = $path;  
-  }  
-  
-  if(strlen($DBFILE) == 0)
-  {
-    echo '<script>alert("Database not available")</script>';
-    die ('<div style="padding-left:150px">Database not available</div>');
+  // Use custom path if supplied
+  if ($DBPath !== null) {
+      $DBFILE = $DBPath;
   }
 
-  $db = SQLite3_connect(true);
-  
-  if(!$db)
-  {
-    echo '<script>alert("Error connecting to the database")</script>';
-    die ('<div style="padding-left:150px">Error connecting to the database</div>');
+  if (strlen($DBFILE) == 0) {
+      echo '<script>alert("Database not available")</script>';
+      die('<div style="padding-left:150px">Database not available</div>');
+  }
+
+  try {
+      $db = new CustomDatabaseWrapper($DBFILE);
+  } catch (Exception $e) {
+      echo '<script>alert("Error connecting to the database: ' . $e->getMessage() . '")</script>';
+      die('<div style="padding-left:150px">Error connecting to the database</div>');
   }
 
   $db->exec('PRAGMA journal_mode = wal;');  
 }
 
 
+
 // # Open DB once and keep open
 // # Opening / closing DB frequently actually casues more issues
 OpenDB (); // main