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Posted to java-user@lucene.apache.org by Paul <pa...@gmail.com> on 2004/12/03 23:31:03 UTC
restricting search result
Hi,
how yould you restrict the search results for a certain user? I'm
indexing all the existing data in my application but there are certain
access levels so some users should see more results then an other.
Each lucene document has a field with an internal id and I want to
restrict on that basis. I tried it with adding a long concatenation of
my ids ("+locationId:1 +locationId:3 + ...") but this throws a "More
than 32 required/prohibited clauses in query." exception.
Any suggestions?
thx!
Paul
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Re: restricting search result
Posted by Sergiu Gordea <gs...@ifit.uni-klu.ac.at>.
Paul wrote:
>Hi,
>how yould you restrict the search results for a certain user? I'm
>indexing all the existing data in my application but there are certain
>access levels so some users should see more results then an other.
>Each lucene document has a field with an internal id and I want to
>restrict on that basis. I tried it with adding a long concatenation of
>my ids ("+locationId:1 +locationId:3 + ...") but this throws a "More
>than 32 required/prohibited clauses in query." exception.
>Any suggestions?
>thx!
>Paul
>
>
What about indexing security levels with the documents, as numeric value
and adding the constrains you need on this field?
I asume that the search will be faster in this case.
Sergiu
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Re: restricting search result
Posted by Paul Elschot <pa...@xs4all.nl>.
On Saturday 04 December 2004 15:44, Erik Hatcher wrote:
> On Dec 4, 2004, at 6:44 AM, Paul wrote:
> >> One way to restrict results is by using a Filter.
> >
> > but a filter is applied after the whole search is performed, isn't it?
>
> Incorrect. A filter is applied *before* the search truly occurs - in
> other words it reduces the search space.
Currently a filter is applied during search, after the document
score is computed, but before a document is added to the search results.
In practice, the score computation is much less work than the I/O, so
a filter does reduce the search space.
A filter might also be used to reduce the I/O for searching, but Lucene
doesn't do that now, probably because there was little to gain.
Regards,
Paul Elschot.
P.S. The code doing the filtering is in IndexSearcher.java, from line 97.
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Re: restricting search result
Posted by Erik Hatcher <er...@ehatchersolutions.com>.
On Dec 4, 2004, at 6:44 AM, Paul wrote:
>> One way to restrict results is by using a Filter.
>
> but a filter is applied after the whole search is performed, isn't it?
Incorrect. A filter is applied *before* the search truly occurs - in
other words it reduces the search space.
Here is a code example using an "owner" field to filter on:
public class SecurityFilterTest extends TestCase {
private RAMDirectory directory;
protected void setUp() throws Exception {
directory = new RAMDirectory();
IndexWriter writer = new IndexWriter(directory,
new WhitespaceAnalyzer(), true);
// Elwood
Document document = new Document();
document.add(Field.Keyword("owner", "elwood"));
document.add(Field.Text("keywords", "elwoods sensitive info"));
writer.addDocument(document);
// Jake
document = new Document();
document.add(Field.Keyword("owner", "jake"));
document.add(Field.Text("keywords", "jakes sensitive info"));
writer.addDocument(document);
writer.close();
}
public void testSecurityFilter() throws Exception {
TermQuery query = new TermQuery(new Term("keywords", "info"));
IndexSearcher searcher = new IndexSearcher(directory);
Hits hits = searcher.search(query);
assertEquals("Both documents match", 2, hits.length());
QueryFilter jakeFilter = new QueryFilter(
new TermQuery(new Term("owner", "jake")));
hits = searcher.search(query, jakeFilter);
assertEquals(1, hits.length());
assertEquals("elwood is safe",
"jakes sensitive info", hits.doc(0).get("keywords"));
}
}
If you index a field that can be used for filtering purposes,
QueryFilter will do the trick nicely. One recommendation when using a
filter though - be sure to keep the instance around over multiple
searches. QueryFilter first does a TermQuery on the term provided to
pre-screen the documents available to the Query passed to the search
method. Since you're doing this on a per-user basis, my recommendation
is to keep their filter, once created, around in their session (in a
web application) or wherever appropriate in another type of
environment.
The above code example is directly from Lucene in Action. I will make
the complete source code distribution available early this coming week,
as soon as Manning releases the electronic book edition. We have been
told the e-book will be available from http://www.manning.com/hatcher2
on Monday. Rest assured Otis or I will announce it as soon as it's
officially there.
Erik
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Re: restricting search result
Posted by Paul <pa...@gmail.com>.
The thing with the different indexes sound too complecated because the
users (and their rights) as well as the index itself change quite
often.
> One way to restrict results is by using a Filter.
but a filter is applied after the whole search is performed, isn't it?
I thought it might be faster to restrict the search space in advance
> Using a + before each term requires them all, ie. uses AND, which
> would normally have an empty result for an Id field.
d'oh, yes of course..
> You might prefer this query concatenation:
>
> +(locationId:1 locationId:3 ...)
ok, that sounds very nice and works fine. But I will have a closer
look at the filter as well.
Thank you all
Paul
P.S. someone without gmail account? mail me
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Re: restricting search result
Posted by Paul Elschot <pa...@xs4all.nl>.
Paul,
On Friday 03 December 2004 23:31, you wrote:
> Hi,
> how yould you restrict the search results for a certain user? I'm
One way to restrict results is by using a Filter.
> indexing all the existing data in my application but there are certain
> access levels so some users should see more results then an other.
> Each lucene document has a field with an internal id and I want to
> restrict on that basis. I tried it with adding a long concatenation of
> my ids ("+locationId:1 +locationId:3 + ...") but this throws a "More
> than 32 required/prohibited clauses in query." exception.
> Any suggestions?
Using a + before each term requires them all, ie. uses AND, which
would normally have an empty result for an Id field.
You might prefer this query concatenation:
+(locationId:1 locationId:3 ...)
It effectively OR's the locationId content query and requires
only one of the terms to match.
In this case using a Filter would probably be better, though.
Regards,
Paul
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Re: restricting search result
Posted by Otis Gospodnetic <ot...@yahoo.com>.
This is entirely application-specific. As the simplest approach, you
can index each user's documents in a separate index and use
(Parallel)MultiSearcher to search appropriate indices (which ones are
appropriate to search has to be a part of your app's access control
logic).
Otis
--- Paul <pa...@gmail.com> wrote:
> Hi,
> how yould you restrict the search results for a certain user? I'm
> indexing all the existing data in my application but there are
> certain
> access levels so some users should see more results then an other.
> Each lucene document has a field with an internal id and I want to
> restrict on that basis. I tried it with adding a long concatenation
> of
> my ids ("+locationId:1 +locationId:3 + ...") but this throws a "More
> than 32 required/prohibited clauses in query." exception.
> Any suggestions?
> thx!
> Paul
>
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> To unsubscribe, e-mail: lucene-user-unsubscribe@jakarta.apache.org
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>
>
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