NOTE: You are looking at documentation for an older release. For the latest information, see the current release documentation.
Highlighting Usage
editHighlighting Usage
editAllows to highlight search results on one or more fields.
The implementation uses either the lucene highlighter or fast-vector-highlighter.
See the Elasticsearch documentation on highlighting for more detail.
Fluent DSL example
edits => s
.Query(q => q
.Match(m => m
.Field(f => f.Name.Suffix("standard"))
.Query("Upton Sons Shield Rice Rowe Roberts")
)
)
.Highlight(h => h
.PreTags("<tag1>")
.PostTags("</tag1>")
.Encoder(HighlighterEncoder.Html)
.Fields(
fs => fs
.Field(p => p.Name.Suffix("standard"))
.Type("plain")
.ForceSource()
.FragmentSize(150)
.Fragmenter(HighlighterFragmenter.Span)
.NumberOfFragments(3)
.NoMatchSize(150),
fs => fs
.Field(p => p.LeadDeveloper.FirstName)
.Type(HighlighterType.Fvh)
.PreTags("<name>")
.PostTags("</name>")
.BoundaryMaxScan(50)
.PhraseLimit(10)
.HighlightQuery(q => q
.Match(m => m
.Field(p => p.LeadDeveloper.FirstName)
.Query("Kurt Edgardo Naomi Dariana Justice Felton")
)
),
fs => fs
.Field(p => p.LeadDeveloper.LastName)
.Type(HighlighterType.Unified)
.PreTags("<name>")
.PostTags("</name>")
.HighlightQuery(q => q
.Match(m => m
.Field(p => p.LeadDeveloper.LastName)
.Query(LastNameSearch)
)
)
)
)
Object Initializer syntax example
editnew SearchRequest<Project>
{
Query = new MatchQuery
{
Query = "Upton Sons Shield Rice Rowe Roberts",
Field = "name.standard"
},
Highlight = new Highlight
{
PreTags = new[] { "<tag1>" },
PostTags = new[] { "</tag1>" },
Encoder = HighlighterEncoder.Html,
Fields = new Dictionary<Field, IHighlightField>
{
{
"name.standard", new HighlightField
{
Type = HighlighterType.Plain,
ForceSource = true,
FragmentSize = 150,
Fragmenter = HighlighterFragmenter.Span,
NumberOfFragments = 3,
NoMatchSize = 150
}
},
{
"leadDeveloper.firstName", new HighlightField
{
Type = "fvh",
PhraseLimit = 10,
BoundaryMaxScan = 50,
PreTags = new[] { "<name>" },
PostTags = new[] { "</name>" },
HighlightQuery = new MatchQuery
{
Field = "leadDeveloper.firstName",
Query = "Kurt Edgardo Naomi Dariana Justice Felton"
}
}
},
{
"leadDeveloper.lastName", new HighlightField
{
Type = HighlighterType.Unified,
PreTags = new[] { "<name>" },
PostTags = new[] { "</name>" },
HighlightQuery = new MatchQuery
{
Field = "leadDeveloper.lastName",
Query = LastNameSearch
}
}
}
}
}
}
Example json output.
{
"query": {
"match": {
"name.standard": {
"query": "Upton Sons Shield Rice Rowe Roberts"
}
}
},
"highlight": {
"pre_tags": [
"<tag1>"
],
"post_tags": [
"</tag1>"
],
"encoder": "html",
"fields": {
"name.standard": {
"type": "plain",
"force_source": true,
"fragment_size": 150,
"fragmenter": "span",
"number_of_fragments": 3,
"no_match_size": 150
},
"leadDeveloper.firstName": {
"type": "fvh",
"phrase_limit": 10,
"boundary_max_scan": 50,
"pre_tags": [
"<name>"
],
"post_tags": [
"</name>"
],
"highlight_query": {
"match": {
"leadDeveloper.firstName": {
"query": "Kurt Edgardo Naomi Dariana Justice Felton"
}
}
}
},
"leadDeveloper.lastName": {
"type": "unified",
"pre_tags": [
"<name>"
],
"post_tags": [
"</name>"
],
"highlight_query": {
"match": {
"leadDeveloper.lastName": {
"query": "Stokes"
}
}
}
}
}
}
}
Handling Responses
editresponse.ShouldBeValid();
foreach (var highlightsInEachHit in response.Hits.Select(d => d.Highlights))
{
foreach (var highlightField in highlightsInEachHit)
{
if (highlightField.Key == "name.standard")
{
foreach (var highlight in highlightField.Value.Highlights)
{
highlight.Should().Contain("<tag1>");
highlight.Should().Contain("</tag1>");
}
}
else if (highlightField.Key == "leadDeveloper.firstName")
{
foreach (var highlight in highlightField.Value.Highlights)
{
highlight.Should().Contain("<name>");
highlight.Should().Contain("</name>");
}
}
else if (highlightField.Key == "leadDeveloper.lastName")
{
foreach (var highlight in highlightField.Value.Highlights)
{
highlight.Should().Contain("<name>");
highlight.Should().Contain("</name>");
}
}
else
Assert.True(false, $"highlights contains unexpected key {highlightField.Key}");
}
}