How to post to user's facebook feed

问题

I need to post to user's facebook feed.

Based on several other SO questions I came up with the following posting request:

let request = GraphRequest(graphPath: "me/feed", parameters: ["message" : "Hello world"], accessToken: accessToken, httpMethod: .POST, apiVersion: GraphAPIVersion.defaultVersion)
request.start({ (response, requestResult) in

    switch requestResult {
    case .failed(let error):
        print("error in graph request:", error)

    case .success(let graphResponse):
        if let responseDictionary = graphResponse.dictionaryValue {
            print(responseDictionary)
        }
    }
})

This fails due to

error =         {
    code = 200;
    "fbtrace_id" = GMp2cebddNb;
    message = "(#200) Requires either publish_actions permission, or manage_pages and publish_pages as an admin with sufficient administrative permission";
    type = OAuthException;
};

Based on the message, the problem seemed to be an easy to solve - all I need is to get either publish_actions, or manage_pages and publish_pages permissions. Based on this SO question, this seemed easy and I ended up in wrapping the code for posting with this:

let loginManager = LoginManager()
loginManager.logIn([PublishPermission.custom("publish_actions")], viewController: self) { (result) in

    print(">> \(AccessToken.current?.grantedPermissions)")

    switch result {

    case .cancelled:
        print(">>>> Cancelled")

    case .failed(let error):
        print(">>>> Error: \(error)" )

    case .success(grantedPermissions: _, declinedPermissions: _, token: let accessToken):
        print(">>>> Logged in!")
        let request = GraphRequest(graphPath: "me/feed", parameters: ["message" : post], accessToken: accessToken, httpMethod: .POST, apiVersion: GraphAPIVersion.defaultVersion)
        request.start({ (response, requestResult) in

            switch requestResult {
            case .failed(let error):
                print("error in graph request:", error)
                break
            case .success(let graphResponse):
                if let responseDictionary = graphResponse.dictionaryValue {
                    print(responseDictionary)
                }
            }
        })
    }
}

Now the "funny" part is, that then the facebook SDK shows a page telling me that I previously logged in to my app using Facebook and asks me if I would like to continue. When I press Continue, the SafariViewController dismisses and the .cancelled branch gets executed. What is going on here? I haven't cancelled, nor have I been asked to grant permissions to publish anything on my feed.

P.S.: I tried logging out first (loginManager.logOut() and/or AccessToken.current = nil), in that case the .success branch executes but again with the same error "(#200) Requires either publish_actions permission, or manage_pages and publish_pages as an admin with sufficient administrative permission".

The AccessToken.current.grantedPermissions in that case contains:

Set([FacebookCore.Permission(name: "user_friends"),
    FacebookCore.Permission(name: "publish_pages"), 
    FacebookCore.Permission(name: "user_location"), 
    FacebookCore.Permission(name: "email"), 
    FacebookCore.Permission(name: "user_likes"), 
    FacebookCore.Permission(name: "pages_show_list"), 
    FacebookCore.Permission(name: "manage_pages"), 
    FacebookCore.Permission(name: "user_photos"), 
    FacebookCore.Permission(name: "public_profile"), 
    FacebookCore.Permission(name: "user_posts"), 
    FacebookCore.Permission(name: "user_birthday")])

So no publish_actions permission! Why does the login go through successfully while not granting me the permission that I ask for? Moreover, I obviously have "manage_pages" and "publish_pages", so why is that not enough?