Terms starting with "R"
Raft Consensus Algorithm
A consensus algorithm designed to be understandable — Raft elects a leader who coordinates all writes, replicates log entries to followers, and ensures that committed entries are never lost even when servers fail.
3mo ago
architecture advanced
RAG — Retrieval-Augmented Generation
1
An LLM architecture that fetches relevant documents from an external knowledge base before generating a response, grounding answers in retrieved facts rather than training data alone.
3mo ago
ai_ml intermediate
readonly Classes (PHP 8.2)
PHP 8.2+
PHP 8.2 readonly classes make all promoted properties readonly automatically — the cleanest way to define immutable value objects and DTOs.
3mo ago
php beginner
readonly Properties (PHP 8.1)
PHP 8.1+
PHP 8.1 readonly properties can only be written once (in the constructor) — enforcing immutability without verbose accessor boilerplate.
3mo ago
php beginner
Redis
PHP 7.0+
An in-memory key-value data store used in PHP applications for caching, session storage, queues, rate limiting, and pub/sub — providing sub-millisecond data access compared to database queries.
3mo ago
performance beginner
Reducing Cyclomatic Complexity Techniques
Cyclomatic complexity counts independent code paths — reduce it by early returns, extracting conditions to named functions, using lookup tables, and replacing switch/if chains with polymorphism.
3mo ago
quality intermediate
Refactoring Boolean Flag Parameters
Boolean flags as function parameters obscure intent — replace with enums, separate functions, or named options objects for self-documenting APIs.
3mo ago
quality intermediate
Regex Flags (i, g, m, s, x, u)
PHP 5.3+
Modifiers appended to a regex pattern that change matching behaviour — case-insensitivity, multiline mode, dotall mode, extended whitespace, and Unicode awareness.
3mo ago
regex beginner
register_globals Era & Why It Was Dangerous
PHP 3.0+
PHP 4 shipped with register_globals=On by default — injecting GET/POST/COOKIE values as global variables, making PHP synonymous with insecurity until it was off-by-default in PHP 4.2.
3mo ago
php intermediate
Remote Code Execution (RCE)
A vulnerability allowing an attacker to run arbitrary code on the server — the most severe class of web vulnerability, typically achieved through eval(), unserialise(), file upload flaws, or OS command injection.
3mo ago
security intermediate
Replace Magic Literal with Symbolic Constant
Magic literals (numbers/strings hardcoded without context) should become named constants — MAX_RETRIES = 3 is self-documenting; the literal 3 is not.
3mo ago
quality beginner
requestAnimationFrame — Smooth Animations
HTML5
requestAnimationFrame(callback) schedules a function to run before the browser's next repaint — the correct way to animate in JavaScript, producing smooth 60fps motion and automatically pausing when the tab is hidden.
3mo ago
javascript intermediate
ResizeObserver API
HTML5
ResizeObserver watches element size changes without polling — more efficient than resize event listeners and works for any element, not just the window.
3mo ago
javascript intermediate
Responsive Design
1
A CSS approach where layouts adapt to different screen sizes using fluid grids, flexible images, and media queries — one codebase that works across mobile, tablet, and desktop.
3mo ago
mobile beginner
Return Type Declarations (PHP 7.0)
PHP 7.0+
PHP 7.0 return type declarations (:int, :string, :void, :static, :never) enable functions to declare what they return — making return contract violations detectable at runtime and by static analysis.
3mo ago
php beginner
Role-Based Access Control (RBAC)
An authorisation model where permissions are assigned to roles, and roles are assigned to users — checking 'can this role perform this action?' rather than 'can this specific user?'
3mo ago
security intermediate
ReferenceError — Undefined Variables
ES2015
ReferenceError is thrown when accessing a variable that hasn't been declared — unlike undefined which is a declared variable with no value.
3mo ago
javascript beginner
register_globals Risk & Legacy Code
PHP 3.0+
register_globals automatically created PHP variables from GET/POST/COOKIE data — removed in PHP 5.4. Legacy code using it is critically vulnerable to variable injection.
3mo ago
security intermediate
Reactive Patterns — Observer & Pub/Sub in JavaScript
ES2015
EventEmitter, CustomEvent, and pub/sub patterns coordinate state changes across components without tight coupling — common in PHP-rendered pages with JS islands.
3mo ago
javascript intermediate
Read Model Projections
Denormalised views of domain data built by processing event streams — the read side of CQRS, optimised for query performance rather than write consistency.
3mo ago
architecture advanced