[Blacklight-development] blacklight questiosn

[Erik Hatcher]

(I noticed reply goes to the sender - I wonder if we can configure it  
such that replies go to the list?   Bess?)

I'll take a stab at replying....

On Feb 11, 2008, at 11:02 AM, Jonathan Rochkind wrote:
> Hi all, I've started taking a look at the Blacklight code. Very nice
> clean code, nice job. [ Although some more comments wouldn't have  
> hurt! :) ]

ha!

> I see you store the entire marc record in a field, and use that   
> stored
> MARC for display, the index fields are just used for indexing. Which
> makes sense; I understand that right?

Yup.

> I don't understand how the default_controller.rb comes into play.
> Nothing I know about Rails says anything about a "default controller"
> being part of rails--and I don't see any of the other controllers
> extending or including it---so what is this file used for, if  
> anything?
> Is it leftover from a previous version, and should be deleted?

Looks like a leftover to me also, and can be removed.

> I see that I don't think you've handled 'status' (checked out,
> available, etc.) at all, true?

Status is not currently handled - that is correct.

>   Do you handle serial holdings at all
> (ie, showing what the ranges of coverage or individual volumes held  
> are
> for a serial, right in Blacklight?).

No, that is not handled either.  If that info is in the MARC record,  
and this is a display-only sort of need, it should be fairly  
straightforward to address this.  I know nothing about that  
particular corner of MARC though.

> Have you tried to tackle highlighting of _where_ in the record your
> search matched, at all?  Do you know what I mean?

Highlighting is possible, and in fact the underlying query made to  
Solr is requesting highlighting (search keyword highlighting, I mean  
here).   Any field could be selectively highlighted.  Highlighting is  
not currently being rendered though - it was removed from my initial  
prototype in its current incarnation.   You can see it commented out  
in views/catalog/_record.rhtml partial.

> You don't support any kind of fielded search except for limiting by
> facets right now, right? No way to enter a fielded keyword search?

Not true.   The full Solr/Lucene QueryParser is at your disposal  
because Solr's standard request handler is being used (it really  
should be migrated to using DisMax for better relevancy tuning - a  
related topic because that then eliminates user entered fielded  
searches).

But currently, if you know the field names, you can use them using  
this syntax:
<http://wiki.apache.org/solr/SolrQuerySyntax>

Example: author_text:jonathan

The field names are not the most intuitive for end users though, so  
that is an issue.

> And in general, I'm having trouble understanding how the Flare code
> works exactly, what is the heart of both the indexing and the display,
> yes?  Any advice for understanding what's going on there? I admit I
> haven't done much with SOLR; if I understand SOLR, will the Flare API
> map pretty obviously to SOLR functions?

The Flare code is not quite clear to me either :)   It was taken on  
and morphed greatly after my departure, so it is it's own beast I'm  
unfamiliar with.

The heart of the indexing code is scripts/virgo_marc_map.rb - the  
mapping from MARC to Solr.  Flare is not involved at all in indexing,  
if that is what you're asking.

Flare is used purely for searching/displaying results, and keep in  
mind the "Flare" we speak of here is Blacklight's own forked and  
highly customized version of what is in the open source codebase of  
Solr's client/ruby/flare svn tree - no relationship at all at the  
moment.

Best advice for understanding what is going on in code is, as always,  
with the unit tests :)   There appears to be a decent set of tests in  
scripts/test/mapping_test.rb - though I haven't run it myself.

Maybe we can get Matt, forker of Flare, to chime in on this topic too.

	Erik