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This documentation relates to DSpace 1.8.x, an old, unsupported version. Looking for another version? See all documentation.
As of January 2015, DSpace 1.8.x is no longer supported. We recommend upgrading to a more recent version of DSpace. See DSpace Software Support Policy.
OAI-PMH Configuration and Activation
In the following sections, you will learn how to configure OAI-PMH and activate additional OAI-PMH crosswalks. The user is also referred to 9.2OAI-PMH Data Provider for greater depth details of the program.
OAI-PMH Configuration
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<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="a9e2a734-e24e-4939-a099-4835bbacfc6b"><ac:plain-text-body><![CDATA[ |
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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 /[dspace-source]/dspace-oai/dspace-oai-api/src/main/java/org/dspace/app/oai/DSpaceOAICatalog.java to codify the declaration: private final int MAX_RECORDS = 100 to private final int MAX_RECORDS = 30 |
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Activating Additional OAI-PMH Crosswalks
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:
- mets - The manifest document from a DSpace METS SIP.
- mods - MODS metadata, produced by the table-driven MODS dissemination crosswalk.
- qdc - Qualified Dublin Core, produced by the configurable QDC crosswalk. Note that this QDC does not include all of the DSpace "dublin core" metadata fields, since the XML standard for QDC is defined for a different set of elements and qualifiers.
OAI-PMH crosswalks based on Crosswalk Plugins are activated as follows:
Uncomment the appropriate
[dspace]/config/oaicat.properties
of the form:Crosswalks.plugin_name=org.dspace.app.oai.PluginCrosswalk
(whereplugin_name
is the actual plugin's name, e.g. "mets" or "qdc"). These lines are all near the bottom of the file.- You can also add a brand new custom crosswalk plugin. Just make sure that the crosswalk plugin has a lower-case name (possibly in addition to its upper-case name) in the plugin configuration in
dspace.cfg
. Then add a line similar to above to theoaicat.properties
file.
- You can also add a brand new custom crosswalk plugin. Just make sure that the crosswalk plugin has a lower-case name (possibly in addition to its upper-case name) in the plugin configuration in
- Restart your servlet container, e.g. Tomcat, for the change to take effect.
- Verify the Crosswalk is activated by accessing a URL such as
http://mydspace/oai/request?verb=ListRecords&metadataPrefix=mets
DIDL
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
oai.didl.maxresponse
configuration indspace.cfg
Uncomment the DIDL Crosswalk entry from the
[dspace]/config/oaicat.properties
file- Restart your servlet container, e.g. Tomcat, for the change to take effect.
- Verify the Crosswalk is activated by accessing a URL such as
http://mydspace/oai/request?verb=ListRecords&metadataPrefix=didl
OAI-ORE Harvester Configuration
This section describes the parameters used in configuring the OAI-ORE harvester.
OAI-ORE Configuration
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 dspace.cfg will override the system defaults.
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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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<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="cf160dbb-79c0-40bc-a61d-842060652d36"><ac:plain-text-body><![CDATA[ |
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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 |
]]></ac:plain-text-body></ac:structured-macro> |
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The webapp responsible for minting the URIs for ORE Resource Maps. If using oai, the dspace.oai.uri config value must be set. The URIs generated for ORE ReMs follow the following convention for both cases._baseURI/metadata/handle/theHandle/ore.xml}} |
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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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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. |