Show keyword-in-context field in search results

See https://groups.google.com/d/topic/islandora/HIInV8uiEVE/discussion for my post and perhaps some discussion about this...

When a search turns up a newspaper issue or book, it's often unclear why that object was returned (especially in newspaper issues). It would be extremely helpful to present in the search results an excerpt from the field where the keyword was found, to provide some context for the result.

Possible implementation:

I'm not sure how we'd identify which field the keyword is in, but it's mainly a problem for items where the keyword appears in FULL_TEXT_t, so we could start there.
Following the same approach as the "Replace namespaces" feature, we can allow an arbitrary Solr field that doesn't have to actually exist to be added to the results, to display our output.
Grab one or more of the keywords used (somehow?) and search for them in the FULL_TEXT_t field (by default; make the field of choice configurable)
Assign the keyword and X characters before and after it to a string
Add the HTML bold tag around the keyword
Spit it out into the search results

bondjimbond / islandora_metadata_extras

Show keyword-in-context field in search results #18