Hello, one feature I find missing from Hibernate Search is a possibility to easily implement a web search. A good example is a blog app, where you can search contents of posts. A post is a simple entity with a "body" field, which is indexed by Hibernate Search/Lucene. You then have the normal search box, where the user enters his/hers query. And now is the problem: what do to with this query? Solution 1. Pass it unchanged to the query parser, as is done for example in the blog example in Seam. But that will in many cases generate exceptions. For example - when there is an unclosed " or a :. You can of course catch that exception and return to the user an empty result list - but that's not what the user excepts. Solution 2. Escape any special characters (using QueryParser.escape) and then pass it safely to query parser - but then the semantics of all special constructs (like phrases: "...", including/excluding words: +/-, fuzzy searches: ~ etc) stop to work. That is also not what the user expects. My proposed solution. The best way out, in my opinion, is to create a custom query pre-parser. This parser would be very "forgiving" in case of any syntax errors. I think it would be best to support the query syntax that google uses (that's what the users are accustomed to): * standard boolean operators AND, OR * quotes "..." * fuzzy/synonym search ~ (but in front of the word, not in the end) * word inclusion/exclusion: +/- Some Lucene constructs would be disabled, like boosting (^), field- search (field_name:), *, ?. Any special characters in invalid positions would be escaped, for example an unmatched quote or a + without a word following it. The parser wouldn't be only a syntax-repairer, but also perform other operations, like moving the ~ from the beginning of a word to the end, or (maybe) adding a * to the end of each term. The implementation shouldn't be too complicated using either ANTLR/ JavaCC or simply regular expressions and a string builder. Needless to say, this would also be useful in Seam :). What do you think?

Hello, > in fact I was facing similar problems before, however the problem is more > of a Lucene problem than a Hibernate Search one. Sure, but it doesn't mean HS can't solve it :) > There are some threads regarding "error tolerant" query parsers on the > Lucene mailing list. There are several approaches to the problem. > You could catch the ParseException and inspect the error message. > According to some post it should be possible to extract the cause of the > error from the excpetion and maybe modify the query. A simpler approach > might be to use QueryParser.escape() in case a ParseException occurs and > just escape the whole query string. You're right, the parsing error is quite well described (not in string form, but "programatically") in the exception. So implementing what I wrote about earlier would be even easier that I suspected. I'll let you know when I'm done with it :). > I think just using QueryParser.parse() out of the box is most of the times > not sufficient and you always have to write some custom code around query > generation and handling. The question is whether any custom parser is > generic enough to be used in a wide range of applications. I like the idea > of a google > like query parser though. I wonder how Nutch is works in this area. Well, as I wrote, I think that supporting Google-like queries would be a good "generic" parser. If the user builds a simple searchable website (with Seam) and wants a "search" box to search through his content such a parser would be what he expects to have in HS (unless his needs are that simple to just send a "site:www.mysite.com query" query to google :) ). -- Adam _______________________________________________ hibernate-dev mailing list hibernate-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev

Hello, one feature I find missing from Hibernate Search is a possibility to easily implement a web search. A good example is a blog app, where you can search contents of posts. A post is a simple entity with a "body" field, which is indexed by Hibernate Search/Lucene. You then have the normal search box, where the user enters his/hers query. And now is the problem: what do to with this query? Solution 1. Pass it unchanged to the query parser, as is done for example in the blog example in Seam. But that will in many cases generate exceptions. For example - when there is an unclosed " or a :. You can of course catch that exception and return to the user an empty result list - but that's not what the user excepts. Solution 2. Escape any special characters (using QueryParser.escape) and then pass it safely to query parser - but then the semantics of all special constructs (like phrases: "...", including/excluding words: +/-, fuzzy searches: ~ etc) stop to work. That is also not what the user expects. My proposed solution. The best way out, in my opinion, is to create a custom query pre- parser. This parser would be very "forgiving" in case of any syntax errors. I think it would be best to support the query syntax that google uses (that's what the users are accustomed to): * standard boolean operators AND, OR * quotes "..." * fuzzy/synonym search ~ (but in front of the word, not in the end) * word inclusion/exclusion: +/- Some Lucene constructs would be disabled, like boosting (^), field- search (field_name:), *, ?. Any special characters in invalid positions would be escaped, for example an unmatched quote or a + without a word following it. The parser wouldn't be only a syntax-repairer, but also perform other operations, like moving the ~ from the beginning of a word to the end, or (maybe) adding a * to the end of each term. The implementation shouldn't be too complicated using either ANTLR/ JavaCC or simply regular expressions and a string builder. Needless to say, this would also be useful in Seam :). What do you think? -- Adam _______________________________________________ hibernate-dev mailing list hibernate-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev