lasty 0.1.2

A fully typed, async Python wrapper for the Last.fm API

lasty

A fully typed, modern, and asynchronous Python client for the Last.fm API.

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lasty is an asynchronous Python library for interacting with the Last.fm API. Built on top of aiohttp, it provides clean abstractions, robust error handling, auto-pagination, and complete static typing (mypy --strict).

Features

• Asynchronous: Built natively on aiohttp for non-blocking HTTP requests.
• Strictly Typed: Every endpoint, payload, and response is backed by typed frozen dataclasses.
• API Mirroring: Namespaces match the official Last.fm API hierarchy (e.g. client.user.get_info()).
• Error Handling: Dedicated exception hierarchy mapped directly to Last.fm error codes.
• Automatic Retries: Exponential backoff for rate limits (HTTP 429) and temporary server errors (HTTP 5xx).
• Auto-Pagination: iter_* helpers to asynchronously stream through paginated endpoints.
• Request Signing: Automatic MD5 signature generation for write operations like scrobbling.

Installation

pip install lasty

Requires Python 3.10 or higher.

Quick Start

import asyncio
from lasty import LastFM, Period

async def main():
    async with LastFM(api_key="your_api_key") as client:
        # Fetch user information
        user = await client.user.get_info("Smugaski")
        print(f"User: {user.name} | Total Scrobbles: {user.playcount}")

        # Fetch recent tracks
        recent = await client.user.get_recent_tracks("Smugaski", limit=5)
        for track in recent.items:
            if track.now_playing:
                print(f"Now playing: {track.artist_name} - {track.name}")
            else:
                date_str = track.date.text if track.date else 'unknown'
                print(f"Played: {track.artist_name} - {track.name} at {date_str}")

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

Core Concepts

API Namespaces

The lasty client exposes namespaced sub-clients matching the official Last.fm API documentation:

• client.user (e.g. .get_info(), .get_recent_tracks(), .get_top_artists())
• client.artist (e.g. .get_info(), .get_similar(), .search())
• client.album (e.g. .get_info(), .search(), .add_tags())
• client.track (e.g. .get_info(), .scrobble(), .love())
• client.tag (e.g. .get_info(), .get_top_tracks())
• client.chart (e.g. .get_top_artists(), .get_top_tracks())
• client.geo (e.g. .get_top_artists("Poland"))
• client.library (e.g. .get_artists())
• client.auth (e.g. .get_token(), .get_session())

Pagination & Iterators

For endpoints returning paginated lists, lasty offers iter_* companion methods returning AsyncIterator instances:

import asyncio
from lasty import LastFM, Period

async def get_top_artists():
    async with LastFM(api_key="your_api_key") as client:
        async for artist in client.user.iter_top_artists("Smugaski", period=Period.SEVEN_DAY, limit=50, max_items=200):
            print(f"Artist: {artist.name} (Playcount: {artist.playcount})")

Authenticated Write Operations

Write operations (such as scrobbling or loving a track) require api_secret and a user session_key. lasty handles request signing automatically.

import asyncio
import time
from lasty import LastFM

async def auth_examples():
    async with LastFM(
        api_key="your_api_key", 
        api_secret="your_api_secret", 
        session_key="user_session_key"
    ) as client:
        
        # Love a track
        await client.track.love("Rammstein", "Sonne")
        
        # Scrobble a track
        result = await client.track.scrobble(
            artist="Rammstein",
            track="Sonne",
            timestamp=int(time.time()),
        )
        print(f"Scrobble result: {result.accepted} accepted, {result.ignored} ignored.")

Authentication Flow

To acquire a user session_key:

async with LastFM(api_key="key", api_secret="secret") as client:
    token = await client.auth.get_token()
    auth_url = client.auth.get_auth_url(token)
    print(f"Authorize the application at: {auth_url}")
    input("Press Enter after authorizing...")
    
    session = await client.auth.get_session(token)
    print(f"Session Key: {session.key}")
    print(f"User: {session.name}")

Error Handling

API errors raise typed exceptions inheriting from LastFMError:

from lasty import LastFM
from lasty.errors import InvalidParametersError, RateLimitError

async def handle_errors():
    async with LastFM(api_key="your_api_key") as client:
        try:
            await client.user.get_info("nonexistent_user_123456789")
        except InvalidParametersError as e:
            print(f"User not found: {e}")
        except RateLimitError:
            print("Rate limit exceeded.")

Development

Install development dependencies and the package in editable mode:

pip install -e .[dev]

Run tests and type checks:

python -m pytest tests/
mypy lasty --strict

License

This project is licensed under the Apache 2.0 License.