Is there any way to add the field in document but hide it from _source, also document should be analysed and searchable - elasticsearch

Question

I want to add one field to the document which should be searchable but when we do get/search it should not appear under _source.
I have tried index and store options but its not achievable through it.
Its more like _all or copy_to, but in my case value is provided by me (not collecting from other fields of the document.)
I am looking for mapping through which I can achieve below cases.
When I put document :
PUT my_index/_doc/1
{
"title": "Some short title",
"date": "2015-01-01",
"content": "A very long content field..."
}
and do search
GET my_index/_search
output should be
{
"hits" : {
"total" : 1,
"max_score" : 1.0,
"hits" : [
{
"_index" : "my_index",
"_type" : "_doc",
"_id" : "1",
"_score" : 1.0,
"_source" : {
"title" : "Some short title",
"date" : "2015-01-01"
}
}
]
}
}
also when I do the below search
GET my_index/_search
{
"query": {
"query_string": {
"default_field": "content",
"query": "long content"
}
}
}
it should result me
"hits" : {
"total" : 1,
"max_score" : 0.5753642,
"hits" : [
{
"_index" : "my_index",
"_type" : "_doc",
"_id" : "1",
"_score" : 0.5753642,
"_source" : {
"title" : "Some short title",
"date" : "2015-01-01"
}
}
]
}

Answer 1

Simply use source filtering to exclude the content field:
GET my_index/_search
{
"_source": {
"excludes": [ "content" ]
},
"query": {
"query_string": {
"default_field": "content",
"query": "long content"
}
}
}

Answer 2

We can achieve this using below mapping :
PUT my_index
{
"mappings": {
"_doc": {
"_source": {
"excludes": [
"content"
]
},
"properties": {
"title": {
"type": "text",
"store": true
},
"date": {
"type": "date",
"store": true
},
"content": {
"type": "text"
}
}
}
}
}
Add document :
PUT my_index/_doc/1
{
"title": "Some short title",
"date": "2015-01-01",
"content": "A very long content field..."
}
When you run the query to search content on the field 'content' :
GET my_index/_search
{
"query": {
"query_string": {
"default_field": "content",
"query": "long content"
}
}
}
You will get the result with hits as below:
"hits" : {
"total" : 1,
"max_score" : 0.5753642,
"hits" : [
{
"_index" : "my_index",
"_type" : "_doc",
"_id" : "1",
"_score" : 0.5753642,
"_source" : {
"date" : "2015-01-01",
"title" : "Some short title"
}
}
]
}
It hides the field 'content'. :)
Hence achieved it with the help of mapping. You don't need to exclude it from query each time you make get/search call.
More read on source :
https://www.elastic.co/guide/en/elasticsearch/reference/6.6/mapping-source-field.html