Pyodide (Web Serial)

Pyodide serial port implementation using the Web Serial API.

Under Pyodide this module registers a transport for the pyodide:// URI scheme (and for scheme-less device:// fallbacks), backed by the browser’s Web Serial API. Only the async transport PyodideSerialTransport is implemented; there is no synchronous BaseSerial equivalent because Web Serial is promise-based.

Because navigator.serial.requestPort() must be called in response to a user gesture from JavaScript, the JS SerialPort object cannot be obtained from Python. Instead, the host page obtains a SerialPort and hands it to Python via register_js_port(), associating it with a URI path. Subsequent calls to serialx.open_serial_connection() (or the lower-level transport) look the path up in the registry. A SerialPort may also be passed directly via the js_port keyword argument, bypassing the registry.

See Connecting to a Web Serial port under Pyodide for a more complete example.

class serialx.platforms.serial_pyodide.PyodideSerialTransport

Bases: BaseSerialTransport

Async serial transport for Pyodide using the Web Serial API.

__init__(loop, protocol)

Initialize the Pyodide serial transport.

Warning

The Web Serial API does not support software flow control (XON/XOFF). Passing xonxoff=True to connect() is accepted for compatibility but is silently ignored; a warning is logged. Only hardware flow control (RTS/CTS) is honored.

Parameters:

  • loop (AbstractEventLoop)

  • protocol (Protocol)

Return type:

None

async get_modem_pins()

Get modem control bits.

Return type:

ModemPins

write(data)

Write data to the transport.

Parameters:

data (bytes | bytearray | memoryview)

Return type:

None

get_write_buffer_size()

Return the number of bytes currently queued for writing.

Return type:

int

async flush()

Flush write buffers, waiting until all data is written.

Return type:

None

abort()

Close the transport immediately, discarding pending writes.

Return type:

None

close()

Close the transport.

Return type:

None

serialx.platforms.serial_pyodide.register_js_port(path, js_port)

Associate a URL with a JS SerialPort for later connection.

Parameters:

  • path (str)

  • js_port (JsSerialPort)

Return type:

None

serialx.platforms.serial_pyodide.unregister_js_port(path)

Remove the entry for path from the JS port registry, if any.

Parameters:

path (str)

Return type:

None