Extracting matching conditions from querystring - elasticsearch

Question

ElasticSearch Query is formed using query string with multiple AND / OR operators. i.e. ((Condition 1 OR Condition 2) AND (Condition 3 OR Condition 4 OR Condition 5)), based on the condition it provides me multiple documents. For getting exact condition I again loop through all the resultant documents again and mark particular conditions. Is there any simple way to get resultant conditions specific to documents ?
Can anyone provide the better example using NEST API?

Answer 1

I think that what you need is to Highlight the data that made the hit on your query. Highlight functionality of elasticsearch actually marks the text from each search result so the user can see why the document matched the query. The marked text is returned in the response.
Please refer in the elasticsearch documentation in order to understand how this api actually works. Refer in the Nest Documentation in order to see how you can implement it with the Nest library.
For example, using the elasticsearch api imagine the below example:
GET /someIndex/someType/_search
{
"query" : {
"match_phrase" : {
"about" : "rock climbing"
}
},
"highlight": {
"fields" : {
"about" : {}
}
}
}
The same with Nest:
var result = _client.Search<someIndex>(s => s
.Query(q => q
.MatchPhrase(qs => qs
.OnField(e => e.about)
.Query("rock climbing")
)
)
.Highlight(h => h
.OnFields(f => f
.OnField(e => e.about)
)
)
);
The response will be of the below form for each search result (notice the highlight part)
"_score": 0.23013961,
"_source": {
"first_name": "John",
"last_name": "Smith",
"age": 25,
"about": "I love to go rock climbing",
"interests": [ "sports", "music" ]
},
"highlight": {
"about": [
"I love to go <em>rock</em> <em>climbing</em>"
]
}