Likes index

Example.json

DELETE likes_index

PUT likes_index
{
  "mappings": {
    "properties": {
      "user_id": {
        "type": "keyword"
      },
      "comment_id": {
        "type": "keyword"
      }
      
    }
  }
}

# Note the doc id is a combination of user and comment ID.
# This is the equivalent of primary key and can be used for 2 things
# 1) Prevents a user liking a comment more than once
# 2) Allows efficient "un-liking" - simply delete using the id
POST likes_index/_doc/1_1
{
  "user_id": 1,
  "comment_id":1
}
POST likes_index/_doc/2_2
{
  "user_id": 2,
  "comment_id":2
}

POST likes_index/_doc/3_2
{
  "user_id": 3,
  "comment_id":2
}

# Show comments 1, 2 and 3 with number of total likes and knowing which
# were specifically liked by user 1. Comments naturally sorted by number of like docs
# so comment 2 appears before comment 1.
GET likes_index/_search
{
  "query": {
    "terms": {
      "comment_id": [
        1,
        2,
        3
      ]
    }
  },
  "size": 0,
  "aggs": {
    "likeCounts": {
      "terms": {
        "field": "comment_id",
        "size": 10
      }
    },
    "likedByCurrentUser": {
      "filter": {
        "term": {
          "user_id": 1
        }
      },
      "aggs": {
        "likeCounts": {
          "terms": {
            "field": "comment_id",
            "size": 10
          }
        }
      }
    }
  }
}