Nest MultiMatch Field Boost - elasticsearch

Question

I'm trying to boost some fields over others in a multiMatch search.
Looking at the docs I see you can create a Field with boost by doing this
var titleField = Infer.Field<Page>(p => p.Title, 2);
I haven't been able to figure out how that translates to Fields though.
Something like this isn't right
var bodyField = Infer.Field<Page>(p => p.Body);
var titleField = Infer.Field<Page>(p => p.Title, 2);
var metaDescriptionField = Infer.Field<Page>(p => p.MetaDescription, 1.5);
var metaKeywordsField = Infer.Field<Page>(p => p.Keywords, 2);
MultiMatchQuery multiMatchQuery = new MultiMatchQuery()
{
Fields = Infer.Fields<Page>(bodyField, titleField, metaDescriptionField, metaKeywordsField),
Query = search.Term
};
Do I need to use the string names for the fields like
var titleFieldString = "Title^2";
and pass those into Infer.Fields

Answer 1

You can use the strongly typed Infer.Field<T>(); there is an implicit conversion from Field to Fields, and additional fields can be added with .And(). Here's an example
void Main()
{
var client = new ElasticClient();
Fields bodyField = Infer.Field<Page>(p => p.Body);
var titleField = Infer.Field<Page>(p => p.Title, 2);
var metaDescriptionField = Infer.Field<Page>(p => p.MetaDescription, 1.5);
var metaKeywordsField = Infer.Field<Page>(p => p.Keywords, 2);
var searchRequest = new SearchRequest<Page>()
{
Query = new MultiMatchQuery()
{
Fields = bodyField
.And(titleField)
.And(metaDescriptionField)
.And(metaKeywordsField),
Query = "multi match search term"
}
};
client.Search<Page>(searchRequest);
}
public class Page
{
public string Body { get; set; }
public string Title { get; set; }
public string MetaDescription { get; set; }
public string Keywords { get; set; }
}
this yields
{
"query": {
"multi_match": {
"query": "multi match search term",
"fields": [
"body",
"title^2",
"metaDescription^1.5",
"keywords^2"
]
}
}
}
You can also pass an array of Field which also implicitly converts to Fields
var searchRequest = new SearchRequest<Page>()
{
Query = new MultiMatchQuery()
{
Fields = new[] {
bodyField,
titleField,
metaDescriptionField,
metaKeywordsField
},
Query = "multi match search term"
}
};
As well as pass an array of strings
var searchRequest = new SearchRequest<Page>()
{
Query = new MultiMatchQuery()
{
Fields = new[] {
"body",
"title^2",
"metaDescription^1.5",
"keywords^2"
},
Query = "multi match search term"
}
};