Facebook graph API: get the "subcomments" in a tree of a discussion - facebook-graph-api

Question

I am trying to download a Facebook discussion using the graph API. The problem is: the discussion is located in a page, and in a tree-style manner, meaning that there are two types of comments: "main" comments, to the first message, and "subcomments" to the main comments themselves.
It seems that the graph result only shows the "main" comments and doesn't show the subcomments. Here's an example of a comment it returns:
{
"id": "53526364352_1574091",
"can_remove": false,
"created_time": "2014-02-05T10:46:37+0000",
"from": {
"name": "Main commenter",
"id": "5345353"
},
"like_count": 163,
"message": "I am a main comment",
"user_likes": false
},
There is no link or whatever to the subcomments of this main comment (and there are many).
Is there a way to get the subcomments?

Answer 1

If 10101140614002197_8831228 is an ID of a root comment, then you can check for subcomments/replies by requesting COMMENT_ID/comments.
For example:
the root comment: http://graph.facebook.com/10101140614002197_8831228
the subcomment: http://graph.facebook.com/10101140614002197_8831228/comments
this root comment has no subcomments so the data list is empty: https://graph.facebook.com/10101140614002197_8831286/comments

Answer 2

You can use field expansion (curly parenthesis in url) to get nested data
http://graph.facebook.com/{object-id}/comments?fields=id,message,comments{id,message,comments{id,message,comments}}
More info here in the section labeled Nested requests (a.k.a. field expansion).

Answer 3

If you want to traverse and flatten the tree, you can do this:
def get_all_comments(post_or_comment_id):
next_ids = [post_or_comment_id]
results = []
while next_ids:
next_id = next_ids.pop()
comments = get_comments_from_facebook(next_id) # Facebook API call
results += comments
next_ids.extend(c["id"] for c in comments)
return results
Make sure to add parent to the API call so you can replicate the tree.