问题
I'm seeing a discrepancy between the number of likes reported in the Graph API vs the number of entries in the "data" that has the name and ID of the people who liked a post.
- When I view a certain post on Facebook, I see that it has 5 people who have liked it.
- When I use the Graph API to fetch the post, the "likes" field has a "data" field with 3 entries in it, and a "count" field whose value is 5.
- When I use the Graph API to fetch the likes for the post (eg, {post_id}/likes), I get a "data" field with 5 entries in it (and no "count" field).
Clearly the true answer to how many people have liked the post is 5. But then why is there only 3 entries in the "data" when I fetch the post object?
Here's another example of the same discrepancy:
https://graph.facebook.com/40796308305_10150394134258306 returns data for a post whose "likes/data" only has 1 entry in it, but whose "likes/count" says that there are 3. But https://graph.facebook.com/40796308305_10150394134258306/likes returns "data" with 3 entries. Finding that same entry on Coca-Cola's page finds that there are, in fact, 3 people who have liked it.
回答1:
The documentation of the post object doesn't mention that the likes list may be incomplete, and the documentation of the fql stream table explicitly says to use the post object to get the full list, so It's either a bug in the API or in the documentation.
I suspect it may be a deliberate but undesirable "feature" to limit the detailed list for performance reasons, as some posts may have hundreds or even thousands of likes.
It ends up actually causing a huge performance problem as I need to find all posts that have been liked by a particular user, and the only way to do that is to do a separate fetch of likes for each post in the list whose like count is higher than the like list length.
回答2:
2 people have their privacy settings set to not show their name to people who are not their friends.
来源：https://stackoverflow.com/questions/8043467/difference-between-a-posts-likes-count-and-the-likes-data