Snippet library

Copy-ready, tested snippets for Python, Flask, JavaScript, SQL, HTML, CSS and Bash. Open any of them in the playground.

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46 snippets

flask

Signed, expiring links

Make email-verification or reset links that expire, without a database table.

from itsdangerous import URLSafeTimedSerializer, BadSignature, SignatureExpired

serializer = URLSafeTimedSerializer(app.config["SECRET_KEY"], salt="email-verify")

intermediate #auth#email#tokens

python

Slugify a title

Turn any title into a lowercase, URL-safe slug.

import re
import unicodedata


def slugify(text: str) -> str:

beginner #strings#regex#urls

html

Social share meta tags

The tags that control how a link looks on social apps and chat.

<head>
  <title>Bakery pre-orders — Ada Studio</title>
  <meta name="description" content="Order bread online and pick it up warm.">
  <meta property="og:type" content="website">
  <meta property="og:title" content="Bakery pre-orders">

beginner #seo#meta#sharing

css

Sticky footer layout

Keep the footer at the bottom of the window on short pages.

body {
  margin: 0;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;

beginner #layout#flexbox#footer

python

Time a block of code

A tiny context manager that prints how long a block took.

import time
from contextlib import contextmanager


@contextmanager

intermediate #performance#context-manager

sql

Top N per group

The 3 best-selling products in every category with ROW_NUMBER().

SELECT category, product, revenue
FROM (
    SELECT c.name AS category,
           p.name AS product,
           SUM(oi.quantity * oi.unit_price) AS revenue,

advanced #window-functions#ranking#reports

css

Truncate text to N lines

Show an ellipsis after three lines.

.excerpt {
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 3;
  line-clamp: 3;

beginner #typography#text

python

Validate data with dataclasses

Use __post_init__ to reject bad values as soon as an object is created.

from dataclasses import dataclass, field


@dataclass
class Product:

intermediate #dataclasses#validation#types

css

Visible keyboard focus

Show a clear focus ring for keyboard users without showing it on mouse clicks.

:where(a, button, input, select, textarea):focus { outline: none; }
:where(a, button, input, select, textarea):focus-visible {
  outline: 3px solid #2f6bff;
  outline-offset: 2px;
  border-radius: 6px;

beginner #accessibility#focus

bash

Wait until a service is up

Retry until a TCP port answers, with a timeout.

wait_for() {
  local host="$1" port="$2" timeout="${3:-30}"
  for ((i = 0; i < timeout; i++)); do
    if (exec 3<>"/dev/tcp/$host/$port") 2>/dev/null; then
      echo "$host:$port is up"; return 0

intermediate #docker#deploy#networking

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Snippet library

Signed, expiring links

Slugify a title

Social share meta tags

Sticky footer layout

Time a block of code

Top N per group

Truncate text to N lines

Validate data with dataclasses

Visible keyboard focus

Wait until a service is up