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
Go
Fan-Out / Fan-In
Distribute work across N workers (fan-out), then merge their results back into one channel (fan-in). Used when you can't process items strictly in order but want to retain output as one stream.
@admin
Bash
Encrypt / Decrypt File with openssl
Symmetric AES-256-GCM encryption of arbitrary files. Use PBKDF2 + a password (good for backups) or pass an explicit key.
Python
Bulk Insert with executemany
Insert many rows in one round-trip using executemany. Orders-of-magnitude faster than a loop of single inserts — and the driver handles batching/parametrization for you.
TypeScript
groupBy (with key callback)
Group a list into a record keyed by whatever the callback returns. Like Lodash _.groupBy or the new Object.groupBy in modern runtimes. Generic enough to handle string, number, or symbol keys.
PHP
Build WHERE IN with Placeholders
Safely interpolate a variable-length list into a "WHERE col IN (...)" clause. Returns the SQL fragment plus the bound parameters — never concatenate user values into SQL.
PHP
Safe Path Join
Concatenate path segments and produce a normalized canonical path that resists "../" escape attempts. Throws if the result would land outside the given base directory.
Kotlin
Exposed — Kotlin-First ORM
JetBrains' Exposed combines a SQL DSL with a lightweight ORM. Either style is fully type-safe; both compile to plain SQL.
Go
Goroutine Leak Prevention
A goroutine that's blocked forever on a channel send/receive leaks — it's never garbage-collected. Always pair channels with `select { case <-ctx.Done(): return }` to give them an exit path.
Go
JSON Marshal / Unmarshal
`encoding/json` is the standard library JSON parser. `Marshal` produces compact JSON; `MarshalIndent` produces pretty-printed. `Unmarshal` decodes into a typed value (struct, map, or any).
Rust
Walk a Directory Tree
`walkdir` recursively iterates every entry under a path, skipping inaccessible directories cleanly. The standard-library alternative requires manual recursion.
Bash
HMAC-SHA256 with openssl
Sign a payload with a shared secret for webhook verification (Stripe, GitHub, etc.). openssl reads the input from stdin or -in.
Bash
Days Between Two Dates
Convert both dates to epoch seconds, subtract, divide. Works for hours/minutes too with the obvious divisor.
Python
pathlib Quick Reference
Forget os.path.* — pathlib.Path is the modern, OS-aware way to work with paths. Operator overloading for joins, attribute access for components, methods for reads/writes/iterations.
Python
Sliding Window Iterator
Iterate over an iterable with a rolling window of N items. itertools.batched (Python 3.12+) gives you NON-overlapping chunks; this helper gives overlapping ones, common for moving averages or n-gram analysis.
TypeScript
partition — Split by Predicate
Split an array into [pass, fail] in a single pass. Type guard overload lets the truthy bucket get a narrowed type when you pass a `x is T` predicate.
PHP
Get Nested Value by Dot Path
Read deeply-nested array values like Lodash _.get(). Use a "a.b.c" string instead of nested isset checks; returns a default on any missing segment.
PHP
Set Cookie with Modern Options
PHP 7.3+ accepts an options array on setcookie() — use it. Sets HttpOnly, Secure on HTTPS, SameSite=Lax by default, and a sensible expiry.