Facebook API - How to cancel Graph Request

Question

I occasionally need to cancel a FaceBook graph request, but there seems to be no cancel or similar method in their API to do so. At the moment, crashes sometimes occur as th

Answer 1

Updated on 22/April/2012

I update Matt's version with the most up-to-date Facebook iOS SDK. My Project is using ARC, but I include the non-ARC Facebook sources so that I can modify the codes. (Of Course, we need to set the "-fno-objc-arc" flag for Facebook source files). The tricky part is to prevent the memory leak, and I think I am doing it correctly. But When I test it in the instrument, I still see very small amount of memory leak. Fortunately, the details show that they are not related to these codes, so I just assume they are related to the app resource handling.

Here is the code I implemented:

// Add to Facebook.h
- (void)cancelPendingRequest:(FBRequest *)releasingRequest; 

And...

// Add to Facebook.m
- (void)cancelPendingRequest:(FBRequest *) releasingRequest{
    [releasingRequest.connection cancel];
    [releasingRequest removeObserver:self forKeyPath:requestFinishedKeyPath];
    [_requests removeObject:releasingRequest];    
}

And in your project which uses FBRequestDelegate

// Declare this member or property to the .h file
FBRequest * currentFbRequest;

// Declare this method
-(void)cancelFBRequest;

And ...

// In .m file
AppDelegate * appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
// prepare your necessary request data and parameter ...
currentFbRequest = [appDelegate.facebook requestWithGraphPath:@"/me/photos" 
    andParams:params 
    andHttpMethod:@"POST" 
    andDelegate:self];



// Then in the method where you want to cancel
AppDelegate * appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
[appDelegate.facebook cancelPendingRequest:currentFbRequest];
currentFbRequest=nil;