Documentation → Developer Resources

Architecture Overview

Four-layer clean architecture design for maintainability and extensibility.

Design Principles

Developer Sitemap follows clean architecture principles to ensure maintainability, testability, and extensibility:

Separation of Concerns — Each layer has a specific responsibility
Dependency Inversion — High-level modules don’t depend on low-level modules
Open-Closed Principle — Open for extension, closed for modification
Single Responsibility — Each class has one reason to change

Layer Structure

The plugin is organized into four distinct layers, with dependencies flowing inward:

┌─────────────────────────────────────────┐
│              WP Layer                    │  ← WordPress Integration
│  (Hooks, Admin UI, REST, CLI)           │
├─────────────────────────────────────────┤
│         Infrastructure Layer             │  ← Concrete Implementations
│  (URL Providers, Cache, XML Renderer)   │
├─────────────────────────────────────────┤
│          Application Layer               │  ← Orchestration
│  (Sitemap Generator, Config Service)    │
├─────────────────────────────────────────┤
│            Domain Layer                  │  ← Pure PHP (No WordPress)
│  (Entities, Value Objects, Interfaces)  │
└─────────────────────────────────────────┘

Domain Layer

The innermost layer contains pure PHP with no WordPress dependencies. This makes the core logic testable and portable.

Entities

Class	Purpose
`SitemapUrl`	Represents a single URL entry
`SitemapEntry`	Complete sitemap entry with metadata

Value Objects

Class	Purpose
`Priority`	Validated priority value (0.0-1.0)
`ChangeFrequency`	Valid change frequency enum

Interfaces

Interface	Purpose
`UrlProviderInterface`	Contract for URL providers
`CacheInterface`	Contract for caching
`RendererInterface`	Contract for XML rendering

Application Layer

Orchestrates the domain logic and coordinates between layers.

Class	Purpose
`SitemapGenerator`	Coordinates sitemap generation
`ConfigurationService`	Manages plugin settings
`Kernel`	Application bootstrap and DI

Infrastructure Layer

Concrete implementations of domain interfaces.

URL Providers

Provider	Content
`PostUrlProvider`	Blog posts
`PageUrlProvider`	Static pages
`ProductUrlProvider`	WooCommerce products
`TaxonomyUrlProvider`	Categories, tags
`AuthorUrlProvider`	Author archives

Support Classes

Class	Purpose
`TransientCache`	WordPress transients implementation
`XmlRenderer`	XML sitemap generation

WP Layer

WordPress-specific integration code.

Class	Purpose
`AdminMenu`	Admin menu registration
`SitemapController`	Handles sitemap requests
`SettingsController`	Admin settings handling
`DashboardPage`	Dashboard admin page
`SettingsPage`	Settings admin page
`AdvancedPage`	Advanced admin page
`HelpPage`	Help admin page

Directory Structure

developer-sitemap/
├── developer-sitemap.php    # Bootstrap
├── uninstall.php            # Cleanup
├── src/
│   ├── Domain/
│   │   ├── Entity/
│   │   ├── ValueObject/
│   │   └── Interface/
│   ├── Application/
│   │   └── Service/
│   ├── Infrastructure/
│   │   ├── Provider/
│   │   ├── Cache/
│   │   └── Renderer/
│   └── WP/
│       ├── Admin/
│       └── Controller/
├── tests/
│   ├── unit/
│   └── integration/
└── docs/