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Add README, composer.json and LICENSE 

Document what is exported, the node.json structure, versioning and
deduplication, the storage layout, settings and limitations. Package the
module as roblib/ocfl_export under GPL-2.0-or-later, with Islandora and
Paragraphs as suggested packages.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
ocfl-files-and-hierarchy
Paul Pound 5 days ago
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LICENSE
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# OCFL Export
Exports Drupal nodes and media as [OCFL](https://ocfl.io/1.1/spec/) (Oxford
Common File Layout) objects on the filesystem, for digital preservation.
The module is Islandora aware: a node's OCFL object contains the node's
metadata, the binaries of every media that belongs to it (originals,
derivatives, etc.) and its place in the collection hierarchy. It also works on
plain Drupal sites, where it includes files in a node's own file/image fields
and media referenced from the node's fields.
## Requirements
- Drupal 10.5+
- PHP 8.3+
- Core modules: node, user, media (and file)
- Optional: [Islandora](https://github.com/Islandora/islandora) for
`field_media_of`, `field_member_of` and `field_model` support
## Installation
```sh
composer require roblib/ocfl_export
drush en ocfl_export
```
Then configure it at **Administration » Configuration » Content authoring »
OCFL Export Settings** (`/admin/config/content/ocfl-export`).
When upgrading an existing installation, run `drush updatedb` to add new
settings.
## What gets exported
Every node and (optionally) every media entity becomes its own OCFL object.
A node object looks like this:
```
node.json Node metadata (see below)
media/{media uuid}/{filename} Files of each associated media
files/{field name}/{filename} Files in the node's own file/image fields
```
Associated media are:
- media whose "media of" field (Islandora: `field_media_of`) points at the
node, and
- media referenced from any media reference field on the node (for example
`field_representative_image`).
A standalone media object contains `node.json` (the media's metadata) and
`files/{field name}/{filename}`. Media thumbnails generated by Drupal are not
exported.
### node.json
In addition to the node's base properties (`uuid`, `nid`, `title`, `type`,
`created`, `changed`, `status`, `author`) and all of its `fields`, `node.json`
contains:
- `relationships`
- `model`: the Islandora model term (`tid`, `uuid`, `name`, and its
external `uri` when present).
- `member_of`: the node's direct parents, each with `nid`, `uuid`, `title`,
`type` and `model`.
- `hierarchy`: every ancestor path through `member_of`, each ordered from
the root collection down to the direct parent. A node with several parents
has several paths.
- `media`: each associated media's full metadata (including
`field_media_use`), how it is associated with the node (`media_of` and/or
`field:<field name>`) and its `files`.
- `files`: the node's own files.
- `_metadata`: export information. `_metadata.missing_files` lists any file
that could not be read during export; the rest of the object is still saved.
Each file entry gives its `logical_path` inside the object, plus `field`,
`fid`, `uuid`, `filename`, `filemime`, `filesize` and the original Drupal
`uri`.
### Versions and deduplication
Every export creates a new OCFL version. A file whose checksum (sha512) is
already in the object's manifest is not copied again: the new version simply
references the existing copy, so large files that don't change are stored
once. Each copied file is verified against its checksum. Checksums are cached
by file URI, size and modification time so unchanged files aren't re-read on
every export.
Deleting a node or media creates a final version marked `"deleted": true`; the
earlier versions, including their files, are kept.
## Storage layout
The storage root (default `private://ocfl-storage`) uses the
[0003-hash-and-id-n-tuple-storage-layout](https://ocfl.github.io/extensions/0003-hash-and-id-n-tuple-storage-layout.html)
extension. Object IDs are `urn:uuid:{entity uuid}`, and an object is stored at
the first three 3-character tuples of the sha256 of its ID, followed by the
percent-encoded ID:
```
ocfl-storage/
├── 0=ocfl_1.1
├── ocfl_layout.json
├── extensions/0003-hash-and-id-n-tuple-storage-layout/config.json
└── b55/aed/a8b/urn%3auuid%3a11111111-2222-3333-4444-555555555555/
├── 0=ocfl_object_1.1
├── inventory.json
├── inventory.json.sha512
├── v1/
└── v2/
```
To find an object on disk, search for its UUID:
```sh
find /path/to/ocfl-storage -maxdepth 4 -name '*<uuid>*'
```
The module refuses to write into a storage root that declares a different
layout.
## Configuration
| Setting | Default | Description |
|---|---|---|
| Storage Root Path | `private://ocfl-storage` | Stream wrapper URI or absolute path of the storage root. |
| Enable automatic export on node save | on | Export nodes when they (or their media) are saved. |
| Content types to export | all | Limit automatic node export to these types. |
| Enable automatic export on media save | on | Also export each media as its own object. |
| Media types to export | all | Limit standalone media export to these types. |
| Copy files into OCFL objects | on | When off, only metadata is exported. |
| "Media of" field | `field_media_of` | Media field pointing at the owning node. |
| "Member of" field | `field_member_of` | Node field pointing at parent nodes. |
| Model field | `field_model` | Node field holding the model term. |
Leave a field setting empty to disable that feature.
**Islandora sites:** media binaries are already stored in their parent node's
object. Leaving standalone media export on stores them a second time, so you
will usually want to turn it off.
## Exporting
- **Automatically:** saving a node, or inserting, updating or deleting one of
its media, queues the node. Queued nodes are exported once when the request
ends, so saving a node together with several media creates one new version.
This also applies to drush commands. Islandora derivatives arrive in
separate requests, so each derivative creates a version of its parent node.
- **Manually:** the **Export to OCFL** button on a node or media page (requires
the *Export content to OCFL* permission).
- **In bulk:** the **Export to OCFL** action, available to Views bulk
operations on content and media listings.
Users with the *Export content to OCFL* permission see the current export
version on node and media pages, with a link to view the latest `node.json`.
## Permissions
- *Administer OCFL Export*: change the module's settings.
- *Export content to OCFL*: export manually and view export status and JSON.
## Limitations
- Titles stored in `member_of` and `hierarchy` are those at export time.
Renaming a collection does not re-export its descendants; their records
update the next time each is exported.
- Version `user` entries contain only a name (no address), so OCFL validators
report the W008 recommendation.
## License
GPL-2.0-or-later. See [LICENSE](LICENSE).

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{
"name": "roblib/ocfl_export",
"description": "Exports Drupal nodes and media (Islandora aware) as OCFL (Oxford Common File Layout) objects, including their files and collection hierarchy.",
"type": "drupal-module",
"license": "GPL-2.0-or-later",
"keywords": [
"Drupal",
"Islandora",
"OCFL",
"digital preservation"
],
"homepage": "https://git.library.upei.ca/Code/ocfl_export",
"support": {
"issues": "https://git.library.upei.ca/Code/ocfl_export/issues",
"source": "https://git.library.upei.ca/Code/ocfl_export"
},
"authors": [
{
"name": "Robertson Library, University of Prince Edward Island",
"role": "Owner"
},
{
"name": "Paul Pound",
"role": "Maintainer"
}
],
"require": {
"php": ">=8.3",
"drupal/core": "^10.5"
},
"suggest": {
"drupal/islandora": "Adds media discovered via field_media_of, collection hierarchy (field_member_of) and model information to node exports.",
"drupal/paragraphs": "Paragraph fields are serialized into the exported metadata when present."
}
}
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