Facebook Like Button-是否选中？

Question

I'm having trouble finding good documentation about how to use javascript in order to find out if a like button is clicked or not. I can't use an on-click event because the button might already be checked when a user comes onto my page but that seems to be all I can find regarding tracking likes externally (not counting other methods that are no longer supported). Anyone have any experience with such issues? Thanks.

Answer 1

It depends on the Like button. If it's for a Facebook object that has an ID, you can query the like table (but you'll need user_likes permission)

If it's for a URL, it's not really possible: facebook graph api determine if user likes url [stackoverflow]

It it's for a built-in like you could use a cookie to remember the click, or save the click in your own database.

Answer 2

Just to expand on Gil's answer. For built-in likes you can use a batch request consisting of two request: 1) Try to like the object in question 2) If there was no error, delete the like connection

Example batch:

[{"method":"POST", "relative_url":"me/og.likes", "body":"object=<SOME_URL>", "name":"like-attempt", "omit_response_on_success": false},
{"method":"DELETE", "relative_url":"{result=like-attempt:$.id}"}]

If an object was already liked, batch response would be:

[
    {
        "code": 400,
        "headers": [
            ...
            {
                "name": "WWW-Authenticate",
                "value": "OAuth \"Facebook Platform\" \"invalid_request\" \"(#3501) User is already associated to the object object on a unique action type Like. Original Action ID: 143539809123515\""
            }
        ],
        "body": "{\n \"error\": {\n \"message\": \"(#3501) User is already associated to the object object on a unique action type Like. Original Action ID: 143539809123515\",\n \"type\": \"OAuthException\",\n \"code\": 3501\n }\n}"
    },
    null
]

So to check if object was liked, JSON.parse the first response body and look for an error with error code 3501 . Keep in mind that the actual error code is not documented anywhere so it could change, although I don't think it is likely.