Extending Search API

There's much more to the Search API, and you can extend it yourself by writing custom constraints. Custom constraints are useful if you want full control over how a term without a constraint prefix should be handled, want to provide relevance weightings to different constraints, want a constraint to look in multiple places for a match, or want features like implicit phrase boosting. Let's look at how we'd control a term without a constraint prefix.

By default, terms entered into search:search() simply search all text nodes of a document. If we want to control that behavior we can plug in a little code. The following options node says for regular terms to call out to our own search-options.xqy library module to control the behavior. In it we specify exactly where we want to look (i.e. not inside header values) and with what relevance weightings.

import module namespace search = "http://marklogic.com/appservices/search" at "/MarkLogic/appservices/search/search.xqy"; search:search("hello world", <options xmlns="http://marklogic.com/appservices/search"> <term apply="myterm" ns="http://try.marklogic.com/search-options" at="/lib/search-options.xqy"> <empty apply="all-results"/> </term> </options>)

The search-options.xqy library is fairly complex, but it's a lot of boilerplate. The so:myterm() function extracts the simple token and converts it to a complex cts:or-query. It makes sure to use the options passed in on the options node for things like case sensitivity. The important part of this is the cts:or-query definition that dictates where to look for matches and with what relevance weightings.

xquery version "1.0-ml"; module namespace so="http://try.marklogic.com/search-options"; declare default function namespace "http://www.w3.org/2005/xpath-functions"; import module namespace searchdev = "http://marklogic.com/appservices/search/searchdev" at "/MarkLogic/appservices/search/custom-parse.xqy"; declare namespace opt = "http://marklogic.com/appservices/search"; declare function so:term-option-to-search-option($opts as element()?) as element()* { for $opt in $opts/opt:term-option where not(starts-with($opt, "lang=")) return <cts:option>{$opt/string()}</cts:option> }; declare function so:myterm($ps as map:map, $term-elem as element()?) as schema-element(cts:query) { ( let $token := searchdev:current($ps) let $options := so:term-option-to-search-option($term-elem) return <cts:or-query qtextconst="{ $token }"> { cts:element-attribute-word-query(xs:QName("message"), xs:QName("list"), string($token), $options, 2.5) } { cts:element-attribute-word-query(xs:QName("attachment"), xs:QName("file"), string($token), $options, 3) } { cts:element-attribute-word-query(xs:QName("from"), xs:QName("personal"), string($token), $options, 3) } { cts:element-attribute-word-query(xs:QName("from"), xs:QName("address"), string($token), $options, 3) } { cts:element-word-query(xs:QName("subject"), string($token), $options, 2) } { cts:element-word-query(xs:QName("para"), string($token), $options, 1) } { cts:element-word-query(xs:QName("attachpara"), string($token), $options, 0.75) } { cts:element-word-query(xs:QName("quotepara"), string($token), $options, 0.5) } </cts:or-query> , searchdev:advance($ps) ) };

I've installed the library for you. You can't modify it, but you can tweak the search:search() call.