feat: Implement SQLCipher support for database encryption

- Added sqlcipher3 dependency to requirements.txt for SQLCipher integration.
- Modified database connection handling in wrappers.py to support encrypted SQLite databases using the new sqlite+sqlcipher:// URL protocol.
- Updated db.py to handle SQLCipher URLs for SQLAlchemy connections.
- Enhanced Alembic migration environment to support SQLCipher URLs.

backend/open_webui/migrations/env.py

@@ -2,8 +2,8 @@ from logging.config import fileConfig
 
 from alembic import context
 from open_webui.models.auths import Auth
-from open_webui.env import DATABASE_URL
-from sqlalchemy import engine_from_config, pool
+from open_webui.env import DATABASE_URL, DATABASE_PASSWORD
+from sqlalchemy import engine_from_config, pool, create_engine
 
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.
@@ -62,11 +62,35 @@ def run_migrations_online() -> None:
     and associate a connection with the context.
 
     """
-    connectable = engine_from_config(
-        config.get_section(config.config_ini_section, {}),
-        prefix="sqlalchemy.",
-        poolclass=pool.NullPool,
-    )
+    # Handle SQLCipher URLs
+    if DB_URL and DB_URL.startswith('sqlite+sqlcipher://'):
+        if not DATABASE_PASSWORD or DATABASE_PASSWORD.strip() == "":
+            raise ValueError("DATABASE_PASSWORD is required when using sqlite+sqlcipher:// URLs")
+        
+        # Extract database path from SQLCipher URL
+        db_path = DB_URL.replace('sqlite+sqlcipher://', '')
+        if db_path.startswith('/'):
+            db_path = db_path[1:]  # Remove leading slash for relative paths
+        
+        # Create a custom creator function that uses sqlcipher3
+        def create_sqlcipher_connection():
+            import sqlcipher3
+            conn = sqlcipher3.connect(db_path, check_same_thread=False)
+            conn.execute(f"PRAGMA key = '{DATABASE_PASSWORD}'")
+            return conn
+        
+        connectable = create_engine(
+            "sqlite://",  # Dummy URL since we're using creator
+            creator=create_sqlcipher_connection,
+            echo=False
+        )
+    else:
+        # Standard database connection (existing logic)
+        connectable = engine_from_config(
+            config.get_section(config.config_ini_section, {}),
+            prefix="sqlalchemy.",
+            poolclass=pool.NullPool,
+        )
 
     with connectable.connect() as connection:
         context.configure(connection=connection, target_metadata=target_metadata)