setup.sh

# delete index if exists
curl -XDELETE localhost:9200/test_nesting/

# create index with default settings
curl -XPOST localhost:9200/test_nesting/

# create mapping
curl -XPUT localhost:9200/test_nesting/link/_mapping -d '
{
  "link" : {
    "properties" : {
      "url" : {"type" : "string"},
      "sources" : {
        "type": "nested",
        "properties" : {
          "full_name" : {"type" : "string"},
          "screen_name" : {"type" : "string"},
          "external_id" : {"type" : "string", "index" : "not_analyzed"}
        }
      }
    }
  }
}
'

# add some data
curl -XPUT localhost:9200/test_nesting/link/1 -d '
{
   "url": "http://www.google.com",
   "sources": [
      {
        "full_name": "Steve",
        "screen_name": "Stevo19",
        "external_id": 1
      },
      {
        "full_name": "Jim",
        "screen_name": "JimmyJimJim",
        "external_id": 2
      },
      {
        "full_name": "Brian",
        "screen_name": "CoolBrian23",
        "external_id": 3
      }
   ]
}
'

curl -XPUT localhost:9200/test_nesting/link/2 -d '
{
   "url": "http://www.yahoo.com",
   "sources": [
      {
        "full_name": "Steve",
        "screen_name": "Stevo19",
        "external_id": 1
      },
      {
        "full_name": "Mark",
        "screen_name": "Markooose",
        "external_id": 4
      }
   ]
}
'

curl -XPUT localhost:9200/test_nesting/link/3 -d '
{
   "url": "http://www.yahoo.com",
   "sources": [
      {
        "full_name": "Mark",
        "screen_name": "Markooose",
        "external_id": 4
      }
   ]
}
'

curl -XPUT localhost:9200/test_nesting/link/4 -d '
{
   "url": "http://www.facebook.com",
   "sources": [
      {
        "full_name": "Jim",
        "screen_name": "JimmyJimJim",
        "external_id": 2
      },
      {
        "full_name": "Mark",
        "screen_name": "Markooose",
        "external_id": 4
      }
   ]
}
'

test.sh

curl -XPOST 'http://127.0.0.1:9200/test_nesting/link/_search?pretty=1'  -d '
{
  "size": 0,
  "query": {
    "nested": {
      "path": "sources",
      "query": {
        "match_phrase_prefix": {
          "full_name": {
            "query": "St"
          }
        }
      }
    }
  },
  "facets": {
    "author": {
      "terms": {
        "script_field": "String result = \"\"; for (int i = 0; i < doc[\"sources\"].values.size(); i++) { result += doc[\"sources\"].values[i].screen_name + Character.toString(0x02) + doc[\"sources\"].values[i].full_name + Character.toString(0x03) } return result;",
        "size": 10
      }
    }
  }
}
'