MediaFilters: Transforming DSpace Content

MediaFilters: Transforming DSpace Content

DSpace can apply filters to content/bitstreams, creating new content. Filters are included that extract text for full-text searching, and create thumbnails for items that contain images. The media filters are controlled by the MediaFilterManager which traverses the asset store, invoking the MediaFilter subclasses on bitstreams. The file config/mediafilter.cfg contains a list of bitstream format types and the filters that operate on bitstreams of that type. The media filter system is intended to be run from the command line (or regularly as a cron task):

dspace/bin/filter-media

Traverse the asset store, applying media filters to bitstreams, skipping bitstreams that have already been filtered.

dspace/bin/filter-media -f

Apply filters to ALL bitstreams, even if they've already been filtered.

dspace/bin/filter-media -v

Verbose mode - print all extracted text and other filter details to STDOUT.

dspace/bin/filter-media -n

Suppress index creation - by default, a new search index is created for full-text searching. This option suppresses index creation if you intend to run index-all elsewhere.

Adding your own filters is done by creating a sub-class of the MediaFilter class. See the comments in the source file MediaFilter.java for more information. In theory filters could be implemented in any language (C, Perl, etc.) They only need to be invoked by the Java code in the MediaFilter class that you create.