tiny-listener 1.2.1

Description:

tinylistener 1.2.1

A lightweight event framework













Documentation: https://molto0504.github.io/tiny-listener
Source Code: https://github.com/molto0504/tiny-listener

Introduction
Tiny-listener is a lightweight and flexible event framework.
Requirements
Python 3.8+
Installation
$ pip install tiny-listener

Why use tiny-listener

✔ Pure Python.
✔ Lightning-fast, based on native coroutine.
✔ 100% test coverage.

Example
Consider we want to write a program keep listening message received from somewhere (e.g. http request or message queue), when message arrived, we want to execute a series of operations in a certain order, e.g.

step 1: save user data to database
step 2: send email to user

In the development process, we often encounter such problems:

the source of step 1 and step 2 may be different
step 2 may depend on the result of step 1, that is to say, step 2 may need to wait for step 1 to complete
there are many messages, many events, and it is not easy to maintain

Tiny-listener may help you solve these problems:
Create a file example.py with:
from tiny_listener import Event, Listener, Param


class App(Listener):
async def listen(self):
ctx = self.new_ctx()
ctx.trigger_event("step 2: send email to [email protected]")
ctx.trigger_event("step 1: save Alice's data to database", data={"age": 35})


app = App()


@app.on_event("step 1: save {username}'s data to database")
async def step_1(event: Event, username: Param):
age = event.data["age"]
print(f"Step-1: Save data done!, {username=}, {age=}")


@app.on_event("step 2: send email to {email}")
async def step_2(event: Event, email: Param):
await event.wait_event_done("step_1")
print(f"Step-2: Send email done!, {email=}")

Run it:
$ tiny-listener example:app
>>> Save data done!, username='Alice', age=35
>>> Send email done!, email='[email protected]'

How it works

Create your own Listener and listen something(e.g. port, queue ...):

from tiny_listener import Event, Listener, Param


class App(Listener):
async def listen(self):
ctx = self.new_ctx()
ctx.trigger_event("step 2: send email to [email protected]")
ctx.trigger_event("step 1: save Alice's data to database", data={"age": 35})


Add event handler to your listener:

app = App()


@app.on_event("step 1: save {username}'s data to database")
async def step_1(event: Event, username: Param):
age = event.data["age"]
print(f"Step-1: Save data done!, {username=}, {age=}")


@app.on_event("step 2: send email to {email}")
async def step_2(event: Event, email: Param):
await event.wait_event_done("step_1")
print(f"Step-2: Send email done!, {email=}")


Run listener with command:

$ tiny-listener example:app


Tiny-listener will dispatch every event automatically:

>>> Step-1: Save data done!, username='Alice', age=35
>>> Step-2: Send email done!, email='[email protected]'