GOCFL - Go OCFL Library

gocfl is a high-performance Go library for the Oxford Common Filesystem Layout (OCFL). It focuses on the creation, update, validation, and extraction of OCFL Storage Roots and Objects, with a strong emphasis on extensibility, I/O efficiency, and technical metadata indexing.

Note: This repository contains the gocfl library. For the command-line interface, please refer to the gocfl-cli repository.

Features

• OCFL Support: Full support for OCFL v1.0 and v1.1, with experimental support for v2.0.
• Storage Backends:
  • Local Filesystem
  • S3 Cloud Storage (via MinIO Client SDK)
  • Serialization into ZIP Containers (with optional AES Encryption)
• High Performance:
  • Optimized I/O: Files are read and written as few times as possible.
  • Concurrent checksum generation and processing.
• Extensibility: Implements a flexible extension hook system (7 different hooks) for both Storage Root and Object extensions.
• Advanced Capabilities:
  • Technical metadata extraction and indexing.
  • File format migration.
  • Thumbnail generation.
  • METS/PREMIS generation.

Installation

go get github.com/ocfl-archive/gocfl/v3

Basic Usage

The library uses a Unified Factory pattern to ensure consistency across different OCFL versions.

Initializing a Storage Root

import (
    "context"
    "github.com/ocfl-archive/gocfl/v3/pkg/ocfl/factory/factoryimpl"
    "github.com/ocfl-archive/gocfl/v3/pkg/ocfl/version"
    "github.com/ocfl-archive/gocfl/v3/pkg/ocfllogger"
    "github.com/je4/filesystem/v3/pkg/vfs"
)

ctx := context.Background()
logger := ocfllogger.NewNopLogger() // Replace with actual logger

// Create a factory for OCFL 1.1
fact := factoryimpl.NewFactory(version.Version1_1, nil, logger)

// Initialize a storage root
sr := fact.NewStorageRoot(ctx)
// ... configure storage root with FS and extensions ...

Supported Extensions

Community Extensions

• 0001-digest-algorithms
• 0002-flat-direct-storage-layout
• 0003-hash-and-id-n-tuple-storage-layout
• 0004-hashed-n-tuple-storage-layout
• 0006-flat-omit-prefix-storage-layout
• 0007-n-tuple-omit-prefix-storage-layout

Local & Special Extensions

• NNNN-mets: Generation of METS and PREMIS files.
• NNNN-indexer: Technical metadata extraction.
• NNNN-migration: Automatic file format migration on ingest.
• NNNN-thumbnail: Generation of thumbnails for video, images, and PDFs.
• NNNN-filesystem: Preserves filesystem metadata.
• NNNN-pairtree-storage-layout: Support for pairtree layouts.
• NNNN-gocfl-extension-manager: Internal manager for extension execution order.

Documentation

• Package Overview
• OCFL Factory Documentation
• Detailed Extension Docs

License

GOCFL is licensed under the Apache License, Version 2.0. See LICENSE for details.