Ferret talk - Feb 2007 - Which method to use to get content from index with a_a_f?

Hi everybody,

After staring at the a_a_f API for quite sometime now, I decided it''s
time to ask...

Which method should I use to get content from the index without using
highlight? Consider the following controller action:

def preview
  if params[:search].blank? # normal case
    @text = @myfile. # which method do I use here to get the :text from
the index???
  else # if we come from the search results page
    @text = @myfile.highlight(params[:search], { :field => :text,
:excerpt_length => :all, :pre_tag => ''[highlight]'',
:post_tag =>
''[/highlight]'' })
  end
end

I didn''t store my text in the database, only in the index. When
I''m
coming from a search I use the highlight method, so the term I searched
for gets highlighted, but how do I get the text from the index in a
''normal case''. The highlight method feels inappropriate,
because I don''t
want to highlight anything. I don''t see what other method to use.

Thanks in advance!

Mischa.

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On Tue, Feb 06, 2007 at 11:22:39PM +0100, Mischa Berger
wrote:
> Hi everybody,
> 
> After staring at the a_a_f API for quite sometime now, I decided
it''s
> time to ask...
> 
> Which method should I use to get content from the index without using
> highlight? Consider the following controller action:
> 
> def preview
>   if params[:search].blank? # normal case
>     @text = @myfile. # which method do I use here to get the :text from
> the index???
>   else # if we come from the search results page
>     @text = @myfile.highlight(params[:search], { :field => :text,
> :excerpt_length => :all, :pre_tag => ''[highlight]'',
:post_tag =>
> ''[/highlight]'' })
>   end
> end
> 
> I didn''t store my text in the database, only in the index. When
I''m
> coming from a search I use the highlight method, so the term I searched
> for gets highlighted, but how do I get the text from the index in a
> ''normal case''. The highlight method feels inappropriate,
because I don''t
> want to highlight anything. I don''t see what other method to use.
that''s because there is currently no aaf way to do this. 

You can however get a handle to the Ferret::Index instance by calling
YourModel.ferret_index (or YourModel.aaf_index.ferret_index if you''re
using the latest aaf trunk). Now you can query this index instance for
your primary key with something in the lines of "id:#{self.id}", and
then
retrieve field values via the standard ferret api.

Note that this won''t work with a remote index, since the index in this
case is not necessarily on the same machine and therefore cannot be 
accessed via Ferret''s own API.

I already started thinking about a way to integrate this into the API,
maybe via an option to find_by_contents that allows to specify the
fields you want to fetch directly from the index. That could then be
combined with lazy-loading of the ''real'' record from DB for
more speed
when it comes to live-searches and the like.

Jens

 

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Thanks for the tip! I expected aaf to have a method for this, but the 
way you describe works fine.

I''m doing it like this now:
@text = Myfile.ferret_index[@myfile.document_number][:text]

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