Python Bytes is a weekly podcast hosted by Michael Kennedy and Brian Okken. The show is a short discussion on the headlines and noteworthy news in the Python, developer, and data science space.
#291 Wait, you have how many licenses?!?
July 06, 2022
00:32:27
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Michael #1: Python License tracker
- by Tom Nijhof/Nyhof
- Every package depends on other package with sometimes different licenses.
- Tom made a tool to find out what licenses you all need for a project:
- PyTest alone needs 4 different licenses for itself and its dependencies.
- Tensorflow is even worst
Brian #2: undataclass
- Trey Hunner
- As a teaching aid, and to show how much dataclasses do for you, this is a module and an application that converts dataclasses to normal classes, and fills in all of the dunder methods you need.
Example in app:
from dataclasses import dataclass @dataclass() class Point: x: float y: float z: float
Converts to
class Point: __match_args__ = ('x', 'y', 'z') def __init__(self, x: float, y: float, z: float) -> None: self.x = x self.y = y self.z = z def __repr__(self): cls = type(self).__name__ return f'{cls}(x={self.x!r}, y={self.y!r}, z={self.z!r})' def __eq__(self, other): if not isinstance(other, Point): return NotImplemented return (self.x, self.y, self.z) == (other.x, other.y, other.z)
Note on
NotImplemented
:- It just means, “I don’t know how to compare this”, and Python will try
__eq__
on theother
object. If that also raisesNotImplemented
, aFalse
is returned.
- It just means, “I don’t know how to compare this”, and Python will try
- The default is the above with
@dataclass(frozen=True, slots=True)
and adds the methods:fronzen=True
gives you implementations of__hash__
,__setattr__
,__delattr__
,__getstate__
,__setstate__
,- Essentially raises exception if you try to change the contents, and makes your objects hashable.
slots=True
adds the line:__slots__ = (``'``x',
'``y``'``,
'``z``'``)
.- This disallows adding new attributes to objects at runtime. See Python docs
- Trey wrote two posts about it:
- Turns out, this is a cool example for AST and structural pattern matching.
- Notes from the “how I made..” article:
- "I used some tricks I don't usually get to use in Python. I used:
- Many very hairy
**match**
-**case**
blocks which replaced even hairierif
-elif
blocks - A sentinel object to keep track of a location that needed replacing
- Python's
**textwrap.dedent**
utility, which I feel should be more widely known & used - slice assignment to inject one list into another
- The
ast
module'sunparse
function to convert an abstract syntax tree into Python code”
Michael #3: Qutebrowser
- via Martin Borus
- Qutebrowser is a keyboard-focused browser with a minimal GUI."
- It's Python powered
- Whats more important - doesn't force you to use it's Vim-based shortcuts, the mouse
- still works. But you usually don't need it: Because on any page, a keypress on the "f" key will show, you every clickable think and a letter combination to enter to click this.
Brian #4: asyncio and web applications
- A collection of articles
- Quart is now a Pallets project
- P G Jones, maintainer of Quart and Hypercorn
- “Quart, an ASGI re-implementation of the Flask API has joined the Pallets organization. This means that future development will be under the Pallets governance by the Pallets maintainers.
- Our long term aim is to merge Quart and Flask to bring ASGI support directly to Flask.
- “When to use Quart?”
- “Quart is an ASGI framework utilising async IO throughout, whereas Flask is a WSGI framework utilising sync IO. It is therefore best to use Quart if you intend to use async IO (i.e. async/await libraries) and Flask if not. Don't worry if you choose the 'wrong' framework though, as Quart supports sync IO and Flask supports async IO, although less efficiently.”
- Using async and await, from Flask docs
- Flask has some support of async/await since Flask 2.0
- But it’s still a WSGI application.
- “Deciding whether you should use Flask, Quart, or something else is ultimately up to understanding the specific needs of your project.”
- Should You Use AsyncIO for Your Next Python Web Application?
- Steven Pate
- A cool “brief history of Python web server interfaces”
- Discussion of the Python servers and frameworks for both WSGI and ASGI
- Recommendation: Do you need async? “… most people don’t. WSGI servers and frameworks are usually performant enough.”
Extras
Michael:
- Python Web Conf Talk: HTMX + Flask: Modern Python Web Apps, Hold the JavaScript
- browserosaurus
Joke: Understanding JavaScript