muxy

muxy is a lightweight router for building HTTP services conforming to Granian's Rust Server Gateway Interface (RSGI). It intentionally avoids magic, prioritising explicit and composable code.

uv add muxy

Features

• first-class router composition - modularise your code by nesting routers with no overhead
• correct, efficient routing - explicit route heirarchy so behaviour is always predictable
• lightweight - the core router is little more than a simple datastructure and has no dependencies
• control - control the full HTTP request/response cycle without digging through framework layers
• middleware - apply common logic to path groups simply and clearly

Inspiration

Go's net/http and go-chi/chi are inspirations for muxy. I wanted their simplicity without having to switch language. You can think of the RSGI interface as the muxy equivalent of the net/http HandlerFunc interface, and muxy.Router as an equivalent of chi's Mux.

Examples

Getting started

import asyncio

import uvloop
from granian.server.embed import Server
from muxy import Router
from muxy.rsgi import HTTPProtocol, HTTPScope

async def home(s: HTTPScope, p: HTTPProtocol) -> None:
    p.response_str(200, [], "Hello world!")

async def main() -> None:
    router = Router()
    router.get("/", home)

    server = Server(router)
    try:
        await server.serve()
    except asyncio.CancelledError:
        await server.shutdown()

if __name__ == "__main__":
    uvloop.run(main())

Bigger app

See examples/server.py for a runnable script.

import asyncio
import json
import sqlite3
from json.decoder import JSONDecodeError

import uvloop
from granian.server.embed import Server

from muxy import Router, path_params
from muxy.rsgi import HTTPProtocol, HTTPScope, RSGIHTTPHandler


async def main() -> None:
    db = sqlite3.connect(":memory:")

    router = Router()
    router.not_found(not_found)
    router.method_not_allowed(method_not_allowed)
    router.get("/", home)
    router.mount("/user", user_router(db))

    server = Server(router)
    try:
        await server.serve()
    except asyncio.CancelledError:
        await server.shutdown()


async def not_found(_scope: HTTPScope, proto: HTTPProtocol) -> None:
    proto.response_str(404, [("Content-Type", "text/plain")], "Not found")

async def method_not_allowed(_scope: HTTPScope, proto: HTTPProtocol) -> None:
    proto.response_str(405, [("Content-Type", "text/plain")], "Method not allowed")

async def home(s: HTTPScope, p: HTTPProtocol) -> None:
    p.response_str(200, [("Content-Type", "text/plain")], "Welcome home")


def user_router(db: sqlite3.Connection) -> Router:
    router = Router()
    router.get("/", get_users(db))
    router.get("/{id}", get_user(db))
    router.post("/", create_user(db))
    router.patch("/{id}", update_user(db))
    return router

def get_users(db: sqlite3.Connection) -> RSGIHTTPHandler:
    # closure over handler function to make db available within the handler
    async def handler(s: HTTPScope, p: HTTPProtocol) -> None:
        cur = db.cursor()
        cur.execute("SELECT * FROM user")
        result = cur.fetchall()
        serialized = json.dumps([{"id": row[0], "name": row[1]} for row in result])
        p.response_str(200, [], serialized)

    return handler

def get_user(db: sqlite3.Connection) -> RSGIHTTPHandler:
    async def handler(s: Scope, p: HTTPProtocol) -> None:
        cur = db.cursor()
        user_id = path_params.get()["id"]
        try:
            user_id = int(user_id)
        except ValueError:
            p.response_str(404, [("Content-Type", "text/plain")], "Not found")
            return
        cur.execute("SELECT * FROM user WHERE id = ?", (user_id,))
        result = cur.fetchone()
        if result is None:
            p.response_str(404, [("Content-Type", "text/plain")], "Not found")
            return
        serialized = json.dumps({"id": result[0], "name": result[1]})
        p.response_str(200, [("Content-Type", "application/json")], serialized)

    return handler

def create_user(db: sqlite3.Connection) -> RSGIHTTPHandler:
    async def handler(s: HTTPScope, p: HTTPProtocol) -> None:
        cur = db.cursor()
        body = await p()
        try:
            payload = json.loads(body)
        except JSONDecodeError:
            p.response_str(422, [("Content-Type", "text/plain")], "Invalid json")
            return
        try:
            name = payload["name"]
        except KeyError:
            p.response_str(422, [("Content-Type", "text/plain")], "No name key")
            return
        cur.execute("INSERT INTO user (name) VALUES (?) RETURNING *", (name,))
        result = cur.fetchone()
        serialized = json.dumps({"id": result[0], "name": result[1]})
        p.response_str(201, [("Content-Type", "application/json")], serialized)

    return handler

def update_user(db: sqlite3.Connection) -> RSGIHTTPHandler: ...


if __name__ == "__main__":
    uvloop.run(main())