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
Kotlin
Ktor Client — POST JSON with Serialization
Combine Ktor + kotlinx.serialization: register the JSON plugin, declare `@Serializable` data classes, the client (de)serializes automatically.
@admin
Rust
reqwest GET + JSON Deserialize
`reqwest` is the standard HTTP client. Combined with serde, you can fetch and parse a JSON API response into a typed struct in three lines.
Java
AtomicInteger / LongAdder
Lock-free atomics for shared counters. `AtomicInteger` for low contention; `LongAdder` for high contention (shards internally — much faster under heavy parallel load).
SQL
Sessionization — Group Events into Sessions
Stitch a stream of events into "sessions" where events more than N minutes apart start a new session. Uses LAG + a SUM-OVER trick to assign session IDs.
PHP
Validate Hex Color
Accept #RGB, #RGBA, #RRGGBB, or #RRGGBBAA hex colors (with or without the leading #). Returns the normalized 6/8-digit lowercase form.
PHP
Slack Incoming-Webhook Notification
Fire a quick notification to a Slack channel via an incoming webhook URL. Includes basic markdown-style mentions and an attachment color for severity.
Rust
Clone vs Copy — When to Use Each
Stack-allocated primitives implement `Copy` (auto-duplicated). Heap-owning types like `String` and `Vec` only implement `Clone` (you must explicitly call `.clone()` to opt into the deep copy cost).
SQL
Views and Materialized Views
A view is a named query — no data stored. A materialized view caches the result; refresh it on demand. Great for expensive joins or aggregations that don't need to be real-time.
SQL
STRING_AGG / GROUP_CONCAT
Concatenate values across a group into a single delimited string. PostgreSQL/MSSQL use `STRING_AGG`; MySQL uses `GROUP_CONCAT`; SQLite has both.
Bash
Sort by a Specific Column
Sort takes -k for column-based ordering and -t to set the delimiter. -h sorts human-readable sizes ("1.5G", "300K") correctly.
SQL
Gap Detection — Missing Days / Sequences
Find holes in a series — missing invoice numbers, days with no events, gaps in a sequence. Combine `LAG` (or `generate_series`) with a join to spot them.
Rust
Arc<Mutex<T>> — Shared Mutable State
Share mutable data across threads: `Arc` for the shared ownership, `Mutex` for the synchronized access. Lock with `.lock().unwrap()`; the guard drops the lock on scope exit.
PHP
Detect & Strip Byte Order Mark
Some text editors prepend a UTF-8 BOM (0xEF 0xBB 0xBF) which breaks header() calls, JSON, and PHP output. Detect and strip it defensively when ingesting external files.
Python
Literal + match for Exhaustive Switching
`Literal` pins a value to specific strings/ints. Combine with the match statement (Python 3.10+) and a `_ : assert_never` clause for exhaustiveness — every variant must be handled or mypy yells at you.
Python
asyncio.wait_for — Timeout Wrapper
Cancel a coroutine if it takes longer than `timeout` seconds. Raises asyncio.TimeoutError when fired so the caller can fall back. Python 3.11+ has asyncio.timeout() as a context-manager alternative.
HTML
Figure + Figcaption (Images, Code, Charts)
`<figure>` groups self-contained illustrative content with its caption. Use it for images, code blocks, charts, diagrams — anything that's referenced from the surrounding text but stands on its own.
Kotlin
also — Side Effect, Return Itself
`x.also { ... }` runs a side-effect block with `x` as `it` and returns `x` unchanged. Used for logging, debugging, or asserting mid-chain without breaking it.