nil-xit 0.3.20

Python binding for nil-xit: C++ bridge to frontend

nil-xit

Python binding for nil-xit – a C++ bridge that connects backends to frontend UIs with a tiny, explicit protocol.

Define frames, values, and signals in C++; interact with them from Python. The client can be web, desktop, or any runtime that speaks the protocol.

Features

• Frames – Group values and signals displayed by a UI component
• Two flavors – Unique (one instance) and tagged (keyed by a tag)
• Values – Bidirectional data binding with buffer types (bytes)
• Signals – Events from UI to backend with byte payloads
• Options – Key/value preprocessing hints for the frontend

Installation

pip install nil-xit

Quick Start

import nil_xit
import nil_service

# Create HTTP server on 127.0.0.1:1101
http = nil_service.create_http_server("127.0.0.1", 1101, 100 * 1024 * 1024)

# Setup server with the built-in svelte page
nil_xit.setup_svelte_server(http)

# Create websocket event service
ws = http.use_ws("/ws")

# Create core from web service and websocket event
core = nil_xit.create_core(http, ws)

# Add a frame
frame = core.add_unique_frame(
    "index",
    nil_xit.FileInfo(group="base", path="gui/Demo.svelte"),
)
frame.add_option("index_mode", "demo")

# Add a value with getter and setter (buffer type)
def encode_value() -> bytes:
    return b"hello world"

def decode_value(data: bytes) -> None:
    print(f"value changed: {data.decode('utf-8')}")

value = frame.add_value("my_value", encode_value, decode_value)

# Add a signal handler (payload is bytes; you can ignore it if unused)
def on_button_click(payload: bytes) -> None:
    print(f"Button clicked! payload size: {len(payload)}")
    value.post(b"updated value")

frame.add_signal("click", on_button_click)

# Add preprocessing options for the frontend
frame.add_option("theme", "dark")

# Main loop
while True:
    http.poll()

For a complete example, see sandbox/main.py.

Supported Types

The Python binding supports buffer types only:

• bytes – Binary data passed as buffer_type<T> in C++
  • Values use getter/setter functions that work with bytes
  • Signals pass byte payloads (handlers may ignore the payload argument)

Frames and FileInfo

Frame creation accepts an optional FileInfo that defines the asset group and relative path used by the frontend.

frame = core.add_unique_frame(
    "index",
    nil_xit.FileInfo(group="base", path="gui/Demo.svelte"),
)

Architecture

The Python binding wraps the C API (libnil-xit-c-api.so) which provides access to:

• unique frames – Single-instance UI components
• tagged frames – Multi-instance UI components (keyed by tag)
• values – Bidirectional data binding with buffer types
• signals – Events from UI to backend with byte payloads

Documentation

For detailed API documentation and more examples, visit:

• C++ Documentation
• C API Guide

License

CC BY-NC-ND 4.0

Support

For issues, questions, or contributions, visit the GitHub repository.