SAMCache does not work with Foursquare photo url as key

The caching as implemented in the video Caching our Photos does not work.

After debugging, I discovered that keys with characters before a forward slash will not work, for example, keys consisting of URLs: "http://foursquare.com/image.jpg". Since the urlStrings of the Foursquare photos were used as each photo's key, SAMCache does not recognize the key for some reason, and the photo is never retrieved from cache.

Interestingly, as long as there's no character in front of a forward slash, the key works, e.g. "/image.jpg" works ok.

I opened an issue about this at SAMCache's git repo:
https://github.com/soffes/SAMCache/issues/20

Here is a fix for the photo caching, where I explicitly remove the forward slashes from the urlString to form the key:

-(void)downloadPhotoWithURL:(NSString*) urlString{
    // *** NEED TO REMOVE FORWARD SLASHES TO FORM A VALID KEY THAT WORKS WITH SAMCACHE
    NSString *key = [urlString stringByReplacingOccurrencesOfString:@"/" withString:@""]; 
    UIImage *cachedPhoto = [[SAMCache sharedCache] imageForKey:key];

    if(cachedPhoto){
        self.photoView.image = cachedPhoto;
        return;
    }

... etc ...

}