Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Classy Abstractions @ Python Web Conf
Search
Hynek Schlawack
June 18, 2020
Programming
0
200
Classy Abstractions @ Python Web Conf
Hynek Schlawack
June 18, 2020
Tweet
Share
More Decks by Hynek Schlawack
See All by Hynek Schlawack
Design Pressure
hynek
0
1.5k
Subclassing, Composition, Python, and You
hynek
3
350
On the Meaning of Version Numbers
hynek
0
340
Maintaining a Python Project When It’s Not Your Job
hynek
1
2.4k
How to Write Deployment-friendly Applications
hynek
0
2.6k
Solid Snakes or: How to Take 5 Weeks of Vacation
hynek
2
5.8k
Get Instrumented: How Prometheus Can Unify Your Metrics
hynek
4
11k
Beyond grep – PyCon JP
hynek
1
3.5k
Beyond grep – EuroPython Edition
hynek
1
10k
Other Decks in Programming
See All in Programming
ふつうの技術スタックでアート作品を作ってみる
akira888
0
290
20250704_教育事業におけるアジャイルなデータ基盤構築
hanon52_
4
240
来たるべき 8.0 に備えて React 19 新機能と React Router 固有機能の取捨選択とすり合わせを考える
oukayuka
2
880
エンジニア向け採用ピッチ資料
inusan
0
180
Deep Dive into ~/.claude/projects
hiragram
10
2.2k
今ならAmazon ECSのサービス間通信をどう選ぶか / Selection of ECS Interservice Communication 2025
tkikuc
20
3.8k
deno-redisの紹介とJSRパッケージの運用について (toranoana.deno #21)
uki00a
0
170
Code as Context 〜 1にコードで 2にリンタ 34がなくて 5にルール? 〜
yodakeisuke
0
120
既存デザインを変更せずにタップ領域を広げる方法
tahia910
1
260
Node-RED を(HTTP で)つなげる MCP サーバーを作ってみた
highu
0
120
関数型まつりレポート for JuliaTokai #22
antimon2
0
160
プロダクト志向ってなんなんだろうね
righttouch
PRO
0
170
Featured
See All Featured
Testing 201, or: Great Expectations
jmmastey
42
7.6k
Making the Leap to Tech Lead
cromwellryan
134
9.4k
What’s in a name? Adding method to the madness
productmarketing
PRO
23
3.5k
Building Better People: How to give real-time feedback that sticks.
wjessup
367
19k
Build The Right Thing And Hit Your Dates
maggiecrowley
36
2.8k
ピンチをチャンスに:未来をつくるプロダクトロードマップ #pmconf2020
aki_iinuma
124
52k
A better future with KSS
kneath
239
17k
Fight the Zombie Pattern Library - RWD Summit 2016
marcelosomers
233
17k
BBQ
matthewcrist
89
9.7k
The Illustrated Children's Guide to Kubernetes
chrisshort
48
50k
KATA
mclloyd
30
14k
Building Applications with DynamoDB
mza
95
6.5k
Transcript
Classy Abstractions Hynek Schlawack
[({},),({},)]
Primitive Obsession
Premature Optimization
None
–me, today “You’re wasting precious resources if you use a
high-level language but only use low-level primitives.”
None
PATHLIB
PATHLIB >>> p = Path() / "foo" / "bar"
PATHLIB >>> p = Path() / "foo" / "bar" >>>
p.absolute() PosixPath('/Users/hynek/foo/bar') >>> p.absolute() WindowsPath('C:/Users/Hynek Schlawack/foo/bar')
PATHLIB >>> p = Path() / "foo" / "bar" >>>
p.absolute() PosixPath('/Users/hynek/foo/bar') >>> p.absolute() WindowsPath('C:/Users/Hynek Schlawack/foo/bar') >>> p.name 'bar'
PATHLIB >>> p = Path() / "foo" / "bar" >>>
p.absolute() PosixPath('/Users/hynek/foo/bar') >>> p.absolute() WindowsPath('C:/Users/Hynek Schlawack/foo/bar') >>> p.name 'bar' >>> Path("README.md").read_text() ...
IPADDRESS
IPADDRESS >>> i = ipaddress.ip_address("::1") >>> i.exploded '0000:0000:0000:0000:0000:0000:0000:0001'
IPADDRESS >>> i = ipaddress.ip_address("::1") >>> i.exploded '0000:0000:0000:0000:0000:0000:0000:0001' >>> ipaddress.ip_address("10.23.45.56")
\ in ipaddress.ip_network("10.0.0.0/8") True
• /?a=fetch&content=<php>die(@md5(HelloThinkCMF))</php> • /wp-content/plugins/google-document-embedder/libs/pdf.php? fn=lol.pdf&file=../../../../wp-config.php • /wp-admin/admin-ajax.php?action=kbslider_show_image&img=../ wp-config.php
YARL
YARL >>> u = yarl.URL("https://hynek.me/articles/")
YARL >>> u = yarl.URL("https://hynek.me/articles/") >>> u.host 'hynek.me' >>> u.path
'/articles/'
YARL >>> u = yarl.URL("https://hynek.me/articles/") >>> u.host 'hynek.me' >>> u.path
'/articles/' >>> u / "speaking/" URL('https://hynek.me/articles/speaking/')
YARL >>> u = yarl.URL("https://hynek.me/articles/") >>> u.host 'hynek.me' >>> u.path
'/articles/' >>> u / "speaking/" URL('https://hynek.me/articles/speaking/') >>> u.with_path("about/") URL('https://hynek.me/about/')
>>> u = yarl.URL.build( scheme="redis", user="scott", password="tiger", host="redis.local", port=369, path="/1",
query={"socket_timeout": 42}) >>> u URL('redis://scott:
[email protected]
:369/1?socket_timeout=42')
>>> u = yarl.URL.build( scheme="redis", user="scott", password="tiger", host="redis.local", port=369, path="/1",
query={"socket_timeout": 42}) >>> u URL('redis://scott:
[email protected]
:369/1?socket_timeout=42') >>> redis.ConnectionPool.from_url(str(u))
None
def f(a=False, b=False, c=False): ... f(b=True)
def f(a=False, b=False, c=False): ... f(b=True) def f(what): ... f("b")
None
ENUM from enum import Enum class What(Enum): A = "a"
B = "b" C = "c"
ENUM from enum import Enum class What(Enum): A = "a"
B = "b" C = "c" f(What.A)
ENUM from enum import Enum class What(Enum): A = "a"
B = "b" C = "c" def f(what: What): ... f(What.D) f(What.A)
ENUM from enum import Enum class What(Enum): A = "a"
B = "b" C = "c" def f(what: What): ... f(What.D) f(What.A) error: "Type[What]" has no attribute "D"
@app.route("/") def view(): return { "foo": "bar" }
@app.route("/") def view(): return { "data": { "id": "some-id", "type":
"example", "attributes": { "foo": "bar" } } "links": "http://localhost/", }
@bp.route("/<int:id>", methods=["GET"]) def get_dns_record(id: int) -> APIResult: try: return APIResult(
get_uow().dns_records.get(id) ) except UnknownDNSRecordError: raise_not_found("DNS record", id)
@bp.route("/<int:id>", methods=["GET"]) def get_dns_record(id: int) -> APIResult: try: return APIResult(
get_uow().dns_records.get(id) ) except UnknownDNSRecordError: raise_not_found("DNS record", id)
@bp.route("/", methods=["POST"]) @validated_body def create_dns_record(ndr: CreateDNSRecord) -> APIResult: try: dr_id
= svc.create_record( get_uow(), ndr.domain, # ... ) except PlanError as e: raise APIError( id=error_ids.PLAN_NOT_SUFFICIENT, status="402", title=e.args[0], source={"pointer": "/data/attributes/domain"}, ) # ...
@bp.route("/", methods=["POST"]) @validated_body def create_dns_record(ndr: CreateDNSRecord) -> APIResult: try: dr_id
= svc.create_record( get_uow(), ndr.domain, # ... ) except PlanError as e: raise APIError( id=error_ids.PLAN_NOT_SUFFICIENT, status="402", title=e.args[0], source={"pointer": "/data/attributes/domain"}, ) # ...
@bp.route("/", methods=["POST"]) @validated_body def create_dns_record(ndr: CreateDNSRecord) -> APIResult: try: dr_id
= svc.create_record( get_uow(), ndr.domain, # ... ) except PlanError as e: raise APIError( id=error_ids.PLAN_NOT_SUFFICIENT, status="402", title=e.args[0], source={"pointer": "/data/attributes/domain"}, ) # ...
@bp.route("/", methods=["POST"]) @validated_body def create_dns_record(ndr: CreateDNSRecord) -> APIResult: try: dr_id
= svc.create_record( get_uow(), ndr.domain, # ... ) except PlanError as e: raise APIError( id=error_ids.PLAN_NOT_SUFFICIENT, status="402", title=e.args[0], source={"pointer": "/data/attributes/domain"}, ) # ...
Locked Un- locked
Locked Un- locked Start
Locked Un- locked Insert Coin Start
Locked Un- locked Insert Coin Push Start
Locked Un- locked Insert Coin Push Insert Coin Start
Locked Un- locked Push Insert Coin Push Insert Coin Start
Classes
None
None
None
None
“Dunder” double underscores: •__init__ •__eq__ •...
class Point(namedtuple('Point', ['x', 'y'])): __slots__ = () @property def hypot(self):
return (self.x ** 2 + self.y ** 2) ** 0.5 def __str__(self): return 'Point: x=%6.3f y=%6.3f hypot=%6.3f' % ( self.x, self.y, self.hypot)
class Point(namedtuple('Point', ['x', 'y'])): __slots__ = () @property def hypot(self):
return (self.x ** 2 + self.y ** 2) ** 0.5 def __str__(self): return 'Point: x=%6.3f y=%6.3f hypot=%6.3f' % ( self.x, self.y, self.hypot) >>> Point.__mro__ (<class '__main__.Point'>, <class '__main__.Point'>, <class 'tuple'>, <class 'object'>)
CHARACTERISTIC @attributes( ["a"], defaults={"a": 42} ) class C: pass
@attr.s class Point: x = attr.ib() y = attr.ib() @property
def hypot(self): return (self.x ** 2 + self.y ** 2) ** 0.5 def __str__(self): return 'Point: x=%6.3f y=%6.3f hypot=%6.3f' % ( self.x, self.y, self.hypot)
None
Dataclasses
@dataclasses.dataclass class Point: x: int y: int @attr.dataclass class Point:
x: int y: int
None
• 2.7
• 2.7 • __slots__
• 2.7 • __slots__ • types optional
• 2.7 • __slots__ • types optional • validators/converters
• 2.7 • __slots__ • types optional • validators/converters •
free to innovate
from attrs import define, field @define class Point3D: x: int
y: int z: int = field( validator=positive )
None
• embrace abstractions
• embrace abstractions • don’t be afraid of classes
• embrace abstractions • don’t be afraid of classes •
wear your masks
ox.cx/a @hynek hynek.me vrmd.de