Plan: Replace PFAPI with Operation Log Sync for All Providers

Status: Completed (January 2026)

This plan has been fully implemented. The entire src/app/pfapi/ directory has been deleted. All sync providers now use the unified operation log system via FileBasedSyncAdapter.

Current Implementation:

• Sync providers: src/app/op-log/sync-providers/
• File-based adapter: src/app/op-log/sync-providers/file-based/file-based-sync-adapter.service.ts
• Server migration: src/app/op-log/sync/server-migration.service.ts

Original Goal

Simplify the codebase by removing PFAPI's model-by-model sync and using operation logs exclusively for all sync providers (WebDAV, Dropbox, LocalFile). Migration required for existing users; old PFAPI files kept as backup.

What Was Implemented

Phase 1: Enable Operation Log Sync (All Providers) - DONE

All providers now use operation log sync:

• WebDAV: src/app/op-log/sync-providers/file-based/webdav/
• Dropbox: src/app/op-log/sync-providers/file-based/dropbox/
• LocalFile: src/app/op-log/sync-providers/file-based/local-file/
• SuperSync: src/app/op-log/sync-providers/super-sync/

Phase 2: Migration Logic - DONE

Migration from legacy PFAPI format is handled by ServerMigrationService:

• Checks for existing PFAPI metadata file on remote
• Downloads full state and creates SYNC_IMPORT operation
• Uploads initial snapshot via operation log

Phase 3: PFAPI Code Removal - DONE

The entire src/app/pfapi/ directory has been deleted (~83 files, 2.0 MB).

What was kept (moved to op-log):

• Provider implementations (WebDAV, Dropbox, LocalFile)
• Encryption/compression utilities
• Auth flows

Phase 4: Testing & Cleanup - DONE

• Multi-device sync scenarios tested via E2E tests
• Migration testing completed
• Large operation log handling verified
• All tests pass

Final Architecture

src/app/op-log/
├── sync-providers/
│   ├── super-sync/                 # Server-based sync
│   ├── file-based/                 # File-based providers
│   │   ├── file-based-sync-adapter.service.ts
│   │   ├── webdav/
│   │   ├── dropbox/
│   │   └── local-file/
│   ├── provider-manager.service.ts
│   └── wrapped-provider.service.ts
├── sync/
│   ├── operation-log-sync.service.ts
│   └── server-migration.service.ts
└── ...

Key Decisions Made

• Single-file sync format (sync-data.json) with state snapshot + recent ops
• Content-based optimistic locking via syncVersion counter
• Piggybacking mechanism for concurrent sync handling
• Server migration service handles legacy PFAPI data migration