Init

shared/db.py

@@ -0,0 +1,102 @@
+"""Small sqlite compatibility layer for CPython and MicroPython.
+
+The module exposes a tiny wrapper around the available sqlite driver so the
+same code can run on CPython (`sqlite3`) and MicroPython (`sqlite3` or
+`usqlite`, depending on the port).
+"""
+
+try:
+	import sqlite3 as _sqlite
+	DRIVER_NAME = "sqlite3"
+except ImportError:
+	try:
+		import usqlite as _sqlite
+		DRIVER_NAME = "usqlite"
+	except ImportError as exc:
+		raise ImportError("No sqlite driver found. Expected sqlite3 or usqlite.") from exc
+
+
+def _connect(database_path, **connect_kwargs):
+	if connect_kwargs:
+		try:
+			return _sqlite.connect(database_path, **connect_kwargs)
+		except TypeError:
+			pass
+	return _sqlite.connect(database_path)
+
+
+class Database:
+	"""Lightweight connection wrapper with a consistent API."""
+
+	def __init__(self, database_path, **connect_kwargs):
+		self._database_path = database_path
+		self._connect_kwargs = connect_kwargs
+		self._connection = None
+
+	def open(self):
+		if self._connection is None:
+			self._connection = _connect(self._database_path, **self._connect_kwargs)
+		return self._connection
+
+	def close(self):
+		if self._connection is not None:
+			self._connection.close()
+			self._connection = None
+
+	def commit(self):
+		connection = self.open()
+		if hasattr(connection, "commit"):
+			connection.commit()
+
+	def cursor(self):
+		return self.open().cursor()
+
+	def execute(self, sql, params=None):
+		cursor = self.cursor()
+		if params is None:
+			cursor.execute(sql)
+		else:
+			cursor.execute(sql, params)
+		return cursor
+
+	def executemany(self, sql, params_list):
+		cursor = self.cursor()
+		cursor.executemany(sql, params_list)
+		return cursor
+
+	def fetchone(self, sql, params=None):
+		return self.execute(sql, params).fetchone()
+
+	def fetchall(self, sql, params=None):
+		return self.execute(sql, params).fetchall()
+
+	def executescript(self, script):
+		connection = self.open()
+		if hasattr(connection, "executescript"):
+			return connection.executescript(script)
+		raise NotImplementedError("executescript is not available on this sqlite backend")
+
+	def __enter__(self):
+		self.open()
+		return self
+
+	def __exit__(self, exc_type, exc, traceback):
+		if exc_type is None:
+			self.commit()
+		self.close()
+
+
+def connect(database_path, **connect_kwargs):
+	return Database(database_path, **connect_kwargs)
+
+
+def execute(database_path, sql, params=None, **connect_kwargs):
+	return connect(database_path, **connect_kwargs).execute(sql, params)
+
+
+def fetchone(database_path, sql, params=None, **connect_kwargs):
+	return connect(database_path, **connect_kwargs).fetchone(sql, params)
+
+
+def fetchall(database_path, sql, params=None, **connect_kwargs):
+	return connect(database_path, **connect_kwargs).fetchall(sql, params)