Islandora on FCREPO4

All islandora repositories that are affected by fcrepo4 have been cloned into https://github.com/futures. Several of the changes in tuque and islandora were created with fcrepo3 compatibility so they have been pushed back to islandora's github in an attempt to maintain consistency and make fcrepo3-4 upgrades easier. Currently FCREPO4 on http://islandora.fcrepo.org/fcrepo starts with an empty repository each day. To get Islandora up and running there are a few tasks that need to be run.

Running Islandora on fcrepo4

When running Islandora on top of FCREPO4 there are a few things to note.

1. Visit the islandora configure page (You will have to be logged in to visit this page). This will load the islandora namespace. Namespaces in FCREPO4 need to be registered and by visiting configure page we automatically register the islandora namespace (namespaces require a name and uri in FCREPO4). the configuration page.

Note: fcrepo urls all start with /rest, so describe => /rest/describe, objects => /rest/objects. In the config, make sure your fedora url has the /rest at the end or it will be unable to connect.

2. Navigate to the solutions pack page to make sure content model and default collection objects are installed. Solutions Pack page.

3. If each solution pack dependency is not installed click the install button for each one. You can also reinstall these dependancies from here if you happen to delete a required datastream during testing.

4. At this point you should be able to navigate to a collection object from the solutions pack page or click on the Islandora Repository to view the objects in the repository. Right now clicking on any collection object will list all objects in the repo as relationships haven't really been defined yet.

5. When in the viewing the image collection object you should be able to click on the manage tab then choose collection and add an object to this collection. If all is well you can choose an image object and ingest it.

6. When you are finished and shut down fcrepo4 (every time) the object store will be flushed requiring you to reingest all objects the next time you start fcrepo4.

Known Issues:

1. Editing the metadata will fail as we try to set the object label. Object labels are not yet implemented FCREPO4 but should be.

2. There is currently no notion of RELS-EXT, the datastream can exist but it will not serve the purposes it did in fcrepo3.

3. There is no resource index so no part of the RELS-EXT will be stored in the triple store. This means riqueries will not work (there is no interface for them). An alternative jcr query interface exists and may be suitable to replace it.

4. In fcrepo3 there was ALWAYS a DC datastream on every object. This is currently not true. fcrepo4 objects are not guaranteed to have DC datastreams (but this may change in the future). As a result several blocks of islandora code have been modified to catch the case of a missing DC datastream while maintaining as much backward compatibility with fcrepo3 as possible

5. Several of the fields that tuque uses ($this->datastreamInfo in Datastream.php) have either missing or unfinished fcrepo4 backends. It may not be required to add all of these (adding them as they are needed should suffice). In all cases, the fields exist in tuque, and in most cases the fields exist in fedora, but fcrepo4 accessors have not yet been created so tuque in unaware of them.

6. tuque no longer uses FOXML to perform ingest. Instead it assembles the object and sends each part into fcrepo4 as it is ready. The result is a foxml-less ingestObject function in Repository.php which has thus far been able to reproduce every feature of foxml ingest except the RELS-EXT isMemberOfCollection tag is missing (and since rels-ext is not currently implemented, this may not be a problem).

7. tuque's FoxmlDocument.php has not yet been removed and is still hanging around in case of emergency. It may be safe to delete this file.