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Old Release
This documentation relates to an old version of DSpace, version 3.x. Looking for another version? See all documentation.
This DSpace release is end-of-life and is no longer supported.
In the following sections, you will learn how to configure OAI-PMH and activate additional OAI-PMH crosswalks. The user is also referred to OAI-PMH Data Provider for greater depth details of the program.
The OAI-PMH Interface may be used by other systems to harvest metadata records from your DSpace.
To enable DSpace's OAI-PMH server, just make sure the [dspace]/webapps/oai/
web application is available from your Servlet Container (usually Tomcat).
You can test that it is working by sending a request to: http://\[full-URL-to-OAI-PMH\]/request?verb=Identify
If you're using a recent browser, you should see a HTML page describing your repository. What you're getting from the server is in fact an XML file with a link to an XSLT stylesheet that renders this HTML in your browser (client-side). Any browser that cannot interpret XSLT will display pure XML. The default stylesheet is located in [dspace]/webapps/oai/oai2.xsl
and can be configured by the OAIHandler.styleSheet
config property in [dspace]/config/oaicat.properties
.
More information on the OAI-PMH protocol and its usage is available at: http://www.openarchives.org/pmh/
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="d02a5939-f71d-4932-85d1-a955af7a7248"><ac:plain-text-body><![CDATA[ |
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This is the OAI-PMH URL for DSpace. By default, it is expected to be |
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Max response size for DIDL. This is the maximum size in bytes of the files you wish to enclose Base64 encoded in your responses, remember that the base64 encoding process uses a lot of memory. We recommend at most 200000 for answers of 30 records each on a 1 Gigabyte machine. Ultimately this will change to a streaming model and remove this restriction. Also please remember to allocate plenty of memory, at least 512 MB to your Tomcat. Optional: DSpace uses 100 records as the limit for the oai responses. You can alter this by changing the |
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Maximum number of records to return for OAI-PMH responses. Defaults to 100. |
DSpace comes with an unqualified DC Crosswalk used in the default OAI-PMH data provider. There are also other Crosswalks bundled with the DSpace distribution which can be activated by editing one or more configuration files. How to do this for each available Crosswalk is described below. The DSpace source includes the following crosswalk plugins available for use with OAI-PMH:
Uncomment the appropriate [dspace]/config/oaicat.properties
of the form: Crosswalks.plugin_name=org.dspace.app.oai.PluginCrosswalk
(where plugin_name
is the actual plugin's name, e.g. "mets" or "qdc"). These lines are all near the bottom of the file.
dspace.cfg
. Then add a line similar to above to the oaicat.properties
file.//[full-URL-to-OAI-PMH]/request?verb=ListRecords&metadataPrefix=mets
By activating the DIDL provider, DSpace items are represented as MPEG-21 DIDL objects. These DIDL objects are XML documents that wrap both the Dublin Core metadata that describes the DSpace item and its actual bitstreams. A bitstream is provided inline in the DIDL object in a base64 encoded manner, and/or by means of a pointer to the bitstream. The data provider exposes DIDL objects via the metadataPrefix didl.
The crosswalk does not deal with special characters and purposely skips dissemination of the license.txt file awaiting a better understanding on how to map DSpace rights information to MPEG21-DIDL.
The DIDL Crosswalk can be activated as follows:
Uncomment the didl.maxresponse
configuration in [dspace]/config/modules/oai.cfg
Uncomment the DIDL Crosswalk entry from the [dspace]/config/oaicat.properties
file
//[full-URL-to-OAI-PMH]/request?verb=ListRecords&metadataPrefix=didl
This section describes the parameters used in configuring the OAI-ORE / OAI-ORE harvester (for XMLUI only). This harvester can be used to harvest content (bitstreams and metadata) into DSpace from an external OAI-PMH or OAI-ORE server.
If you are harvesting content (bitstreams and metadata) from an external DSpace installation via OAI-PMH & OAI-ORE, you first should verify that the external DSpace installation allows for OAI-ORE harvesting.
First, that external DSpace must be running both the OAI-PMH interface and the XMLUI interface to support harvesting content from it via OAI-ORE.
You can verify that OAI-ORE harvesting option is enabled by following these steps:
First, check to see if the external DSpace reports that it will support harvesting ORE via the OAI-PMH interface. Send the following request to the DSpace's OAI-PMH interface: http://\[full-URL-to-OAI-PMH\]/request?verb=ListRecords&metadataPrefix=ore
Next, you can verify that the XMLUI interface supports OAI-ORE (it should, as long as it's a current version of DSpace). First, find a valid Item Handle. Then, send the following request to the DSpace's XMLUI interface: http://\[full-URL-to-XMLUI\]/metadata/handle/\[item-handle\]/ore.xml
There are many possible configuration options for the OAI harvester. Most of them are technical and therefore omitted from the dspace.cfg file itself, using hard-coded defaults instead. However, should you wish to modify those values, including them in oai.cfg will override the system defaults.
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="299dbbf3-3461-4ae3-8ad1-080801c0be99"><ac:plain-text-body><![CDATA[ |
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The EPerson under whose authorization automatic harvesting will be performed. This field does not have a default value and must be specified in order to use the harvest scheduling system. This will most likely be the DSpace admin account created during installation. |
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The base url of the OAI-PMH disseminator webapp (i.e. do not include the /request on the end). This is necessary in order to mint URIs for ORE Resource Maps. The default value of |
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The webapp responsible for minting the URIs for ORE Resource Maps. If using oai, the
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Determines whether the harvest scheduler process starts up automatically when the XMLUI webapp is redeployed. |
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harvester.oai.metadataformats.PluginName = \ http://www.openarchives.org/OAI/2.0/oai_dc/, Simple Dublin Core |
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This field can be repeated and serves as a link between the metadata formats supported by the local repository and those supported by the remote OAI-PMH provider. It follows the form |
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harvester.oai.oreSerializationFormat.OREPrefix = \ http://www.w3.org/2005/Atom |
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This field works in much the same way as |
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Amount of time subtracted from the from argument of the PMH request to account for the time taken to negotiate a connection. Measured in seconds. Default value is 120. |
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How frequently the harvest scheduler checks the remote provider for updates. Should always be longer than timePadding . Measured in minutes. Default value is 720. |
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The heartbeat is the frequency at which the harvest scheduler queries the local database to determine if any collections are due for a harvest cycle (based on the harvestFrequency) value. The scheduler is optimized to then sleep until the next collection is actually ready to be harvested. The minHeartbeat and maxHeartbeat are the lower and upper bounds on this timeframe. Measured in seconds. Default value is 30. |
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The heartbeat is the frequency at which the harvest scheduler queries the local database to determine if any collections are due for a harvest cycle (based on the harvestFrequency) value. The scheduler is optimized to then sleep until the next collection is actually ready to be harvested. The minHeartbeat and maxHeartbeat are the lower and upper bounds on this timeframe. Measured in seconds. Default value is 3600 (1 hour). |
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How many harvest process threads the scheduler can spool up at once. Default value is 3. |
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How much time passes before a harvest thread is terminated. The termination process waits for the current item to complete ingest and saves progress made up to that point. Measured in hours. Default value is 24. |
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You have three (3) choices. When a harvest process completes for a single item and it has been passed through ingestion crosswalks for ORE and its chosen descriptive metadata format, it might end up with DIM values that have not been defined in the local repository. This setting determines what should be done in the case where those DIM values belong to an already declared schema. Fail will terminate the harvesting task and generate an error. Ignore will quietly omit the unknown fields. Add will add the missing field to the local repository's metadata registry. Default value: fail. |
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Informational Note: |
When a harvest process completes for a single item and it has been passed through ingestion crosswalks for ORE and its chosen descriptive metadata format, it might end up with DIM values that have not been defined in the local repository. This setting determines what should be done in the case where those DIM values belong to an unknown schema. Fail will terminate the harvesting task and generate an error. Ignore will quietly omit the unknown fields. Add will add the missing schema to the local repository's metadata registry, using the schema name as the prefix and "unknown" as the namespace. Default value: fail. |
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harvester.acceptedHandleServer = \ hdl.handle.net, handle.test.edu |
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A harvest process will attempt to scan the metadata of the incoming items (identifier.uri field, to be exact) to see if it looks like a handle. If so, it matches the pattern against the values of this parameter. If there is a match the new item is assigned the handle from the metadata value instead of minting a new one. Default value: hdl.handle.net . |
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Pattern to reject as an invalid handle prefix (known test string, for example) when attempting to find the handle of harvested items. If there is a match with this config parameter, a new handle will be minted instead. Default value: 123456789 . |
For information on activating & using the OAI-PMH / OAI-ORE Harvester to harvest content into your DSpace, see Harvesting Items from XMLUI via OAI-ORE or OAI-PMH