AIP pointer file
Pointer files have been used to help provide sustainable access to compressed AIPs since Archivematica 1.0. . The documentation about them, below, is currently in progress.
Pointer files can help users ascertain information about their AIPs without needing to consult the Storage Service API or database.
As an example, pointer files include:
- Information about compression, currently used internally by Archivematica itself for Re-ingest or unpacking for delivery via the API
- Information about encryption so that AIPs can be recovered if encrypted.
- Information about where the AIP is stored relative to the storage service. NB. there are some variations, see below.
Describing the location of the AIP
Information about the location of an AIP is stored in a
inside the pointer file:
<mets:fileSec> <mets:fileGrp USE="Archival Information Package"> <mets:file ID="rs_s3-cc53bf2e-0eb9-4d00-a752-8f07c2886fe9" GROUPID="Group-cc53bf2e-0eb9-4d00-a752-8f07c2886fe9" ADMID="amdSec_698926"> <mets:FLocat xlink:href="/var/archivematica/storage_service/aipstore/cc53/.../ex1-cc53bf2e-0eb9-4d00-a752-8f07c2886fe9.7z" LOCTYPE="OTHER" OTHERLOCTYPE="SYSTEM"/> <mets:transformFile TRANSFORMTYPE="decompression" TRANSFORMORDER="1" TRANSFORMALGORITHM="bzip2"/> </mets:file> </mets:fileGrp> </mets:fileSec>
In some storage options that can be configured via the storage service, such as LOCKSS you will see information about the remote location of the AIP:
<mets:fileSec> <mets:fileGrp USE="Archival Information Package"> <mets:file ID="FLocatTest-e0ff9a0e-a7f5-4bee-b9c2-7e2321dde7a6"> <mets:FLocat LOCTYPE="URL" xlink:href="http://lockss1.example.org:8083/ServeContent?url=http://archivematicastorage.example.com/lockssomatic/FLocatTest-e0ff9a0e-a7f5-4bee-b9c2-7e2321dde7a6.7z"/> <mets:transformFile TRANSFORMALGORITHM="bzip2" TRANSFORMORDER="1" TRANSFORMTYPE="decompression"/> </mets:file> </mets:fileGrp> </mets:fileSec>
Note: Not all storage options will show the information about the remote location. Either this information isn't as easy to replay to the user, or it is functionality that was beyond the scope of development of a storage adapter at the time. S3 is a current example where the user would see the path as it is shown above:
and they would need to ascertain for themselves that the location was relative to the S3 location created for use as an package store online.
Accessing a pointer file
Accessing pointer files inside Archivematica can be done by navigating the Dashboard to Archival storage finding a suitable AIP, e.g. at time of writing a compressed AIP, and under Pointer file clicking View. Archivematica will make a call to the Storage Service API to return the file for that AIP. More information can be found about this in the Archivematica documentation under Storing an AIP.
Location of the pointer file inside Storage Service
Pointer files are stored in the Storage Service directories, for example:
You can see where they are stored looking up the Storage Service database:
select locations_location.uuid, locations_location.relative_path, locations_location.description, locations_location.purpose from locations_location inner join locations_package on locations_location.uuid = locations_package.pointer_file_location_id