Tags
#php
#kotlin
#bash
#go
#sql
#rust
#typescript
#html
#java
#python
#files
#utils
#strings
#http
#concurrency
#async
#json
#arrays
#security
#types
#crypto
#database
#dates
#format
Java
ExecutorService — Thread Pools
`ExecutorService` is the modern way to manage threads. Submit Callables/Runnables, get Futures back. Always shutdown the executor — and prefer try-with-resources on Java 19+ where ExecutorService is AutoCloseable.
@admin
HTML
Video Element with Captions
`<video>` with multiple `<source>` formats (MP4 + WebM), `controls`, `poster`, and a captions track via `<track kind="captions">`. All shipped with the browser — no JS player needed.
Kotlin
apply — Configure Object, Return Itself
`x.apply { ... }` runs the block with `x` as `this` (so you call methods/set properties directly) and returns `x`. The canonical builder-style configuration.
Rust
match with Guards, Ranges, and Bindings
`match` arms can have `if` guards, range patterns (`1..=5`), bindings (`x @ pattern`), and ORs (`A | B`). Combine them for very expressive dispatch.
PHP
HTTP Retry with Exponential Backoff
Wrap any HTTP call in a retry loop with capped exponential backoff and jitter. Retries on 5xx / network errors but not on 4xx (those won't fix themselves).
Bash
Cron Entry From Script
Append a cron job idempotently — grep first to avoid duplicates on re-run. Doesn't require editing files manually.
SQL
CREATE TABLE with Constraints
Declare data integrity rules right in the schema — primary keys, foreign keys, unique constraints, NOT NULL, CHECK constraints, defaults. The DB enforces them so application bugs can't corrupt your data.
Python
Retry Decorator with Exponential Backoff
Generic retry decorator: attempts × base delay, exponential ramp, random jitter. Filter retryable exceptions via the `on` tuple so logical errors aren't retried.
SQL
RETURNING — Get Back What You Wrote
PostgreSQL `RETURNING *` returns the rows affected by an INSERT/UPDATE/DELETE — no separate SELECT round-trip needed. SQL Server has `OUTPUT`; MySQL added `RETURNING` in MariaDB and 8.0.31+.
Rust
Untyped JSON with serde_json::Value
When you don't know the JSON shape up-front, parse into `serde_json::Value` and navigate via index / get(). Type-safe pattern matching converts back to Rust types.
Rust
Read a File — Whole / Lines / Bytes
Three common patterns: load it all into memory, iterate line-by-line, or stream bytes. Pick by file size — `read_to_string` is convenient but bad for huge files.
TypeScript
Bearer-Auth Fetch Wrapper
Wrap fetch so every request automatically attaches an Authorization: Bearer header from a token getter. Token can be a static string or a function (useful for refreshing).
Kotlin
Result Type — Safe Error-Returning APIs
`Result<T>` wraps "success or thrown exception" without forcing the caller into try/catch. `runCatching { ... }` is the standard producer.
Kotlin
require / check / requireNotNull
Three contract-style assertions in the stdlib: `require` for inputs (throws `IllegalArgumentException`), `check` for state (throws `IllegalStateException`), `requireNotNull` returns the value smart-cast.
Kotlin
kotlin.test — Basic Tests
`kotlin.test` is the multiplatform test stdlib. `@Test` marks a test; `assertEquals`, `assertTrue`, `assertFailsWith` are the workhorses.
Python
pairwise — Rolling Pair Iterator
`pairwise([a, b, c, d])` yields `(a, b), (b, c), (c, d)` — built into itertools since 3.10. Perfect for "diff consecutive elements" patterns (deltas, rate-of-change, validation between rows).
Rust
String vs &str — The Cheat Sheet
`String` is an owned, growable heap allocation; `&str` is a borrowed view into a UTF-8 buffer. Function params should usually take `&str`; return types use `String` when ownership is needed.