elasticsearch find posts by comments

Question

I'm trying to write a query that finds articles based on their comments.

So if a user is trying to find "chocolates"

{
  type: "article",
  id: "myArticle1",
  title: "something about brown food"
}

{
  body: "I love chocolates!",
  type:"comment",
  commentOf: "myArticle1"
}

In this example I have both documents in the same index and I'm trying to get the "myArticle1" document via the comment matching chocolates in body. How do I do this? Is it with the top_children query?

Answer 1

You can use the parent-child in ES to achieve this:

1. Define the parent (article) and child (comment)
2. Index data. You should know how to index child data as it will difference from normal (need to specify parent in the index request)
3. Use has_child query to query for article that matched some fields in comment

I wrote a full working sample script for it: https://gist.github.com/dqduc/efa66047358dac66461b

You can run it to test and send me your feedback. I guess you're new to ES and parent-child relationship in ES.