Page History
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Enabling OAI-PMH Interface
To enable DSpace's OAI-PMH server, just make sure the {{\ Wiki Markup [dspace
\]/webapps/oai/
}} web application is available from your Servlet Container (usually Tomcat).
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- You can test that it is working by sending a request to: {{
http://\[full-URL-to-OAI-PMH\]/request?verb=Identify
}} - The response should look similar to the response from the DSpace Demo Server: http://demo.dspace.org/oai/request?verb=Identify
More information on the OAI-PMH protocol and its usage is available at: http://www.openarchives.org/pmh/
OAI-PMH Configuration
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="96217b01-3f1a-4dfa-8a20-8801d1d23f37"><ac:plain-text-body><![CDATA[ | Configuration File: Configuration File: | | ]]></ac:plain-text-body></ac:structured-macro> |
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Property: Property: | | ||
Example Value: | | ||
Information Note: | This is the OAI-PMH URL for DSpace. By default, it is expected to be | ||
Property: | | ||
Example Value: | | ||
Informational Note: | 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 | ||
Property: | | ||
Example Value: | | ||
Informational Note: | Maximum number of records to return for OAI-PMH responses. Defaults to 100. |
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- 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:
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- 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 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://\[full-URL-to-OAI-PMH\]/request?verb=ListRecords&metadataPrefix=mets
- The response should be an XML document containing METS, similar to the response from the DSpace Demo Server: http://demo.dspace.org/oai/request?verb=ListRecords&metadataPrefix=mets
- The response should be an XML document containing METS, similar to the response from the DSpace Demo Server: http://demo.dspace.org/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.
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The DIDL Crosswalk can be activated as follows:
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- Uncomment the {{
didl.maxresponse
}} configuration in {{\[dspace
\]/config/modules/oai.cfg
}} Uncomment the DIDL Crosswalk entry from the {{\Wiki Markup [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://\[full-URL-to-OAI-PMH\]/request?verb=ListRecords&metadataPrefix=didl
- The response should be an XML document containing DIDL, similar to the response from the DSpace Demo Server: http://demo.dspace.org/oai/request?verb=ListRecords&metadataPrefix=mets
- The response should be an XML document containing DIDL, similar to the response from the DSpace Demo Server: http://demo.dspace.org/oai/request?verb=ListRecords&metadataPrefix=mets
OAI-PMH / OAI-ORE Harvester
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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: {{Wiki Markup http://\[full-URL-to-OAI-PMH\]/request?verb=ListRecords&metadataPrefix=ore
}}- The response should be an XML document containing ORE, similar to the response from the DSpace Demo Server: http://demo.dspace.org/oai/request?verb=ListRecords&metadataPrefix=ore
- The response should be an XML document containing ORE, similar to the response from the DSpace Demo Server: http://demo.dspace.org/oai/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: {{Wiki Markup http://\[full-URL-to-XMLUI\]/metadata/handle/\[item-handle\]/ore.xml
}}- The response should be an OAI-ORE (XML) document which describes that specific Item. It should look similar to the response from the DSpace Demo Server: http://demo.dspace.org/xmlui/metadata/handle/10673/3/ore.xml
- The response should be an OAI-ORE (XML) document which describes that specific Item. It should look similar to the response from the DSpace Demo Server: http://demo.dspace.org/xmlui/metadata/handle/10673/3/ore.xml
OAI-PMH / OAI-ORE Harvester 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 oai.cfg will override the system defaults.
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.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.
Configuration File: |
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Property: | | ||
Example Value: | | ||
Informational Note: | 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. | ||
Property: | | ||
Example Value: | | ||
Informational Note: | 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 | ||
Property: | | ||
Example Value: | | ||
Informational Note: | The webapp responsible for minting the URIs for ORE Resource Maps. If using oai, the
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Property: | | ||
Example Value: | | ||
Informational Note: | Determines whether the harvest scheduler process starts up automatically when the XMLUI webapp is redeployed. | ||
Property: | | ||
Example Value: |
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Informational Note: | 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 | ||
Property: | | ||
Example Value: |
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Informational Note: | This field works in much the same way as | ||
Property: | | ||
Example Value: | | ||
Informational Note: | 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. | ||
Property: | | ||
Example Value: | | ||
Informational Note: | How frequently the harvest scheduler checks the remote provider for updates. Should always be longer than timePadding . Measured in minutes. Default value is 720. | ||
Property: | | ||
Example Value: | | ||
Informational Note: | 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. | ||
Property: | | ||
Example Value: | | ||
Informational Note: | 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). | ||
Property: | | ||
Example Value: | | ||
Informational Note: | How many harvest process threads the scheduler can spool up at once. Default value is 3. | ||
Property: | | ||
Example Value: | | ||
Informational Note: | 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. | ||
Property: | | ||
Example Value: | | ||
Informational Note: | 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. | ||
Property: | | ||
Example Value: | | ||
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. | ||
Property: | | ||
Example Value: |
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Informational Note: | 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 . | ||
Property: | | ||
Example Value: | | ||
Informational Note: | 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 . |
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