MksDdn Migrate Content

MksDdn Migrate Content is a clean-room migration suite that packages your site into deterministic .wpbkp archives. Each bundle contains a manifest, checksum, database segments, media, selected files, and user decisions, so imports stay predictable.

Why MksDdn Migrate Content?

• Dual export modes – choose Full Site (database + uploads/plugins/mu-plugins/themes) or Selected Content (multi-select posts/pages/CPTs) with or without referenced media.
• Chunked pipeline – large archives stream through REST API endpoints with resume tokens, so multi‑GB transfers survive flaky networks.
• User merge control – compare archive vs current users and decide how to merge conflicts.
• Theme import mode – when a theme archive is detected, choose replace vs merge before applying changes.
• Integrity & safety – .wpbkp archives ship with manifests and checksums; imports verify capabilities, nonces, and disk space before touching data.
• Import preflight – unified import is a two-step flow: run preflight (read-only report), then start the real import from the report without uploading the file again (browser uploads are staged server-side between steps).

Feature Highlights

• Archive format with manifest, checksum, and payload folders (content.json, media/, options/, filesystem slices).
• Media scanner that collects featured images, galleries, attachments referenced inside blocks or shortcodes.
• File-system coverage for wp-content/uploads, wp-content/plugins, wp-content/mu-plugins, wp-content/themes with filters to skip VCS/system files.
• Chunked upload/download JS client with live progress, auto-resume, and graceful fallback to direct transfer.
• Server file import – select backup files directly from wp-content/uploads/mksddn-mc/imports/ directory without browser uploads.
• Custom .wpbkp drag-and-drop uploader with checksum guardrails (UI polish deferred to next milestone, functionality already complete).

Architecture

The plugin follows SOLID principles and WordPress Coding Standards with a clean, modular architecture:

Service Container & Dependency Injection

• Centralized ServiceContainer manages all dependencies
• Service Providers (CoreServiceProvider, AdminServiceProvider, ExportServiceProvider, ImportServiceProvider, ChunkServiceProvider) register services
• All dependencies resolved through container, eliminating direct instantiation
• Full support for interface-based dependency injection

Request Handlers

• ExportRequestHandler – handles export requests
• ImportRequestHandler – delegates to specialized import services (supports unified import via UnifiedImportOrchestrator)
• UserMergeRequestHandler – processes user merge operations
• ThemePreviewRequestHandler – handles theme preview cancel operations
• ChunkRestController – REST API controller for chunked upload/download operations
• All handlers implement corresponding interfaces for testability

Service Layer

• SelectedContentImportService – handles selected content imports
• FullSiteImportService – manages full site imports
• ThemeImportService – handles theme archive imports
• UnifiedImportOrchestrator – orchestrates unified import with automatic type detection; step 1 is always preflight, step 2 runs the real import using a stored file reference
• ImportPreflightService – read-only analysis for unified import preflight
• PreflightReportStore – short-lived transient storage for preflight reports and follow-up import handles (staged browser uploads under wp-content/uploads/mksddn-mc/preflight/, or chunk/server identifiers)
• ImportTypeDetector – detects import type (full site or selected content) from archive file
• ImportFileValidator – validates uploaded files
• ImportPayloadPreparer – prepares import payloads
• ServerBackupScanner – scans and validates backup files on the server
• ResponseHandler – manages redirects and status messages
• NotificationService – handles user notifications
• ProgressService – tracks operation progress
• ErrorHandler – centralized error handling and logging
• UserDiffBuilder – builds user difference comparison
• UserMergeApplier – applies user merge operations
• ThemePreviewStore – stores pending theme import previews
• DeactivationCleanup – clears temporary upload state and service directories when the plugin is deactivated
• PostImportMaintenance – centralizes cache/rewrite cleanup after full import and emergency purge if the database was partially updated; performs global flush plus targeted wp_cache_flush_group() when supported, bumps posts/terms/comments last_changed hooks, exposes mksddn_mc_post_import_object_cache_flush_groups filter, integrates page-cache plugins via best-effort function calls and hooks
• FullImportMaintenance – file-based runtime lock and early 503 gate while a full-site import is running (admin, CLI, cron exempt; REST blocked unless explicitly allowed)

Contracts (Interfaces)

All key components implement interfaces: * ExporterInterface, ImporterInterface * MediaCollectorInterface, ChunkJobRepositoryInterface * UserPreviewStoreInterface, ThemePreviewStoreInterface, UserDiffBuilderInterface, UserMergeApplierInterface * NotificationServiceInterface, ProgressServiceInterface * ArchiveHandlerInterface, ValidatorInterface * Request handler interfaces for all handlers

Error Handling

• Specialized exceptions: ValidationException, FileOperationException, DatabaseOperationException, ImportException, ExportException
• Centralized ErrorHandler for consistent error processing
• Proper logging and user-friendly error messages
• Validation classes: ArchiveValidator, ImportDataValidator, ExportDataValidator, FileValidator

Performance

• BatchLoader for optimized database queries (prevents N+1 problems)
• Efficient media collection with batch processing (AttachmentCollector)
• Chunked transfer for large files via REST API (ChunkRestController)
• Memory-efficient streaming for large archives
• FullArchivePayload for efficient archive payload handling
• ContentCollector for filesystem content collection

Security

• All admin operations check current_user_can('manage_options')
• Nonce verification for all forms and AJAX requests
• REST API endpoints protected with permission callbacks
• Input sanitization using WordPress sanitization functions
• Output escaping with esc_html(), esc_attr(), esc_url()
• File upload validation with MIME type checking
• Path traversal protection for server file access (ServerBackupScanner)
• Path traversal protection for archive extraction (full site + theme import)
• SiteUrlGuard prevents accidental site URL changes during import
• ImportLock prevents concurrent import operations
• DomainReplacer safely handles URL replacement during migrations