There are a few kinds of Cartridge, and many of each kind are included in a standard Virtuoso installation.
An Extractor Cartridge processes a Resource of a given format, extracting RDF according to rules appropriate to that format. External data does not come into play; only the content of the Resource fed to the Sponger.
These Cartridges handle open formats — typically community-developed, openly-documented, and freely-licensed data structures.
These Cartridges handle closed formats — typically proprietary; sometimes undocumented; possibly licensed to no-one except the format originator. Sometimes data may not be parsed as desired or expected, as many of these Cartridges have required reverse-engineering of the data format in question.
A Meta Cartridge submits a Resource to a third-party Web Service for processing. Returned RDF supplements the RDF generated by Extractor and other Meta Cartridges. Locally generated RDF may also be submitted to the third-party services, instead-of or in-addition-to the original Resource itself.
Default Sponger behavior is for all installed Meta Cartridges to be brought to bear on all submitted Resources.
- Complete list of supported Meta Cartridges
- Meta Cartridge Usage via REST Request
- Parametrized Examples of Meta Cartridge Usage via REST Request
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- Virtuoso Sponger
- The OpenLink Data Explorer Extension
- Meshups (links and lookups across Web 2.0 Services and LOD Cloud