Elasticsearch NEST highlighting the attachment content - elasticsearch

Question

In Elasticsearch 5.6.3 I installed ingest-attachment plugin. I am trying to set the term vector property to WithPositionOffsets in attachment's content. Where should I set this property to see highligted result in my search?
The Document POCO is below:
public class Document
{
public int Id { get; set; }
public string Path { get; set; }
public string Content { get; set; }
public Attachment Attachment { get; set; }
}
Here is the CreateIndex function with mappings.
var indexResponse = client.CreateIndex(documentsIndex, c => c
.Settings(s => s
.Analysis(a => a
.Analyzers(ad => ad
.Custom("windows_path_hierarchy_analyzer", ca => ca
.Tokenizer("windows_path_hierarchy_tokenizer")
)
)
.Tokenizers(t => t
.PathHierarchy("windows_path_hierarchy_tokenizer", ph => ph
.Delimiter('\\')
)
)
)
)
.Mappings(m => m
.Map<Document>(mp => mp
.AutoMap()
.AllField(all => all
.Enabled(false)
)
.Properties(ps => ps
.Text(s => s
.Name(n => n.Path)
.Analyzer("windows_path_hierarchy_analyzer")
)
.Attachment(at => at.
Name(n => n.Attachment.Content)
.FileField(ff => ff
.Name("Content")
.TermVector(TermVectorOption.WithPositionsOffsets)
.Store()))
//.Text(s => s
// .Name(n => n.Attachment.Content)
// .TermVector(TermVectorOption.WithPositionsOffsets)
// .Store(true)
//)
.Object<Attachment>(a => a
.Name(n => n.Attachment)
.AutoMap()
)
)
)
)
);
into the .Mappings part I used a FileField to set termvector and store property. But the result is below:
{
"documents": {
"mappings": {
"document": {
"_all": {
"enabled": false
},
"properties": {
"attachment": {
"properties": {
"author": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"content": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"content_length": {
"type": "long"
},
"content_type": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"date": {
"type": "date"
},
"detect_language": {
"type": "boolean"
},
"indexed_chars": {
"type": "long"
},
"keywords": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"language": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"name": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"title": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
},
"content": {
"type": "attachment",
"fields": {
"content": {
"type": "text",
"store": true,
"term_vector": "with_positions_offsets"
},
"author": {
"type": "text"
},
"title": {
"type": "text"
},
"name": {
"type": "text"
},
"date": {
"type": "date"
},
"keywords": {
"type": "text"
},
"content_type": {
"type": "text"
},
"content_length": {
"type": "integer"
},
"language": {
"type": "text"
}
}
},
"id": {
"type": "integer"
},
"path": {
"type": "text",
"analyzer": "windows_path_hierarchy_analyzer"
}
}
}
}
}
}
So I can't see the highlight property in my query result. How should I do this?

Answer 1

To work with the ingest-attachment plugin, don't map the Attachment property as an attachment data type; this mapping is for the mapper-attachment plugin which is deprecated in 5.x and removed in 6.x.
I wrote a blog post about using ingest-attachment with .NET which includes an example mapping for Attachment; essentially, map it as an object data type and map the Content property on it as a text data type with .TermVector(TermVectorOption.WithPositionsOffsets) applied. You'll need to create this mapping in an index before indexing any documents with attachments into it.