Ds-datahandler(Digitale Samlinger) by the Royal Danish Library.

Notice

OAI-PMH harvest is just the first implementation feature in ds-datahandler. More features will implemented later.

OAI harvest

Ds-datahandler can harvest OAI from different OAI-PMH targets and ingest the metadata for the records into ds-storage. Having the metadata in ds-storage makes access much easier and faster for other applications. The metadata for each record will be UTF-8 encoded before ingested into ds-storage. Invalid XML encoding characters will be replaced or removed.

OAI targets configuration

The project yaml-file contains the configuration for each OAI-PMH target.

The below table describes the parameters to configure a OAI-PMH target

Property	Description
name	The name used to specify when starting a new import
url	The base url to OAI-PMH service
set	Parameter to the OAI-server if the server has multiple collections (optional)
metadataPrefix	Parameter to the OAI-server to specify the format for the metadata. Options depend on the OAI target.
user	User if the OAI-server require basic authentication (optional)
password	Password if the OAI-server require basic authentication (optional)
origin	The origin when sending records from this OAI target to ds-storage.
	The origin must be configured in DS-storage. ID will be {origin}:{id in OAI record}
description	Human text to give further description if needed

Full import and delta import

For each OAI target configured you can request a full import or a delta import from the OAI collection. A full import will harvest all records from to OAI target. A delta import will only import records with a datestamp later than the last record recieved in either an earlier full import or delta import.

Storing last harvest datestamp

The yaml property file specificed a folder on the filesystem to store the last datestamps for each OAI target. The file will only contain a single line with an UTC timestamp identical to the last record successfully send ds-storage from that OAI target.

Configure the yaml property file

Besides all the OAI targets it must also definere the property for the folder to store the datestamps. Also the properties host,port,baseurl to the ds-storage server to submit the records to.

More about the OAI-PMH protocol

See: link

Requirements

• Maven 3
• Java 11

Setup

Build & run

Due to license, the following jar pm-dependency file must be copied to a local repository or .m2-folder. https://mvnrepository.com/artifact/com.kaltura/KalturaClient/3.3.1

Build with

mvn package

Setup required to run the project local

Create local yaml-file: Take a copy of 'ds-datastore-behaviour.yaml' and name it'ds-datastore-environment.yaml' Edit the timestamps.folder variable to where you want the timestamps store. If the folder does not exist it will be created.

Test the webservice with

mvn jetty:run

Swagger UI

The Swagger UI is available at http://localhost:9071/ds-datahandler/api/, providing access to both the v1 version of the GUI.

Deployment to a server (development/stage/production).

Install Tomcat9 server

Configure tomcat with the context enviroment file conf/ocp/ds-datastore.xml. Notice it points to the location on the file system where the yaml and logback file are located.

Edit conf/ds-datastore.logback.xml

Make a ds-datastore.yaml file. (Make a copy of /conf/ds-datastore-environment.yaml rename it, and edit the properties). To ingest into a local ds-storage tomcat server, you need to have ds-storage running (just mvn jetty:run and change jetty port pom plugin)

Using a client to call the service

This project produces a support JAR containing client code for calling the service from Java. This can be used from an external project by adding the following to the pom.xml:

<!-- Used by the OpenAPI client -->
<dependency>
    <groupId>org.openapitools</groupId>
    <artifactId>jackson-databind-nullable</artifactId>
    <version>0.2.2</version>
</dependency>

<dependency>
    <groupId>dk.kb.license</groupId>
    <artifactId>ds-datahandler</artifactId>
    <version>1.0-SNAPSHOT</version>
    <type>jar</type>
    <classifier>classes</classifier>
    <!-- Do not perform transitive dependency resolving for the OpenAPI client -->
    <exclusions>
        <exclusion>
          <groupId>*</groupId>
          <artifactId>*</artifactId>
        </exclusion>
    </exclusions>
</dependency>

after this a client can be created with

    DsLicenseClient datahandlerClient = new DsLicenseClient("https://example.com/ds-datahandler/v1");

During development, a SNAPSHOT for the OpenAPI client can be installed locally by running

mvn install

See the file DEVELOPER.md for developer specific details and how to deploy to tomcat.