如何获取JSON格式文件FBRequest requestForMyFriends的结果？

Question

I'm using Objective-C and developing for iPhone.

I'm sending a request for the friends of a logged in user and writing the data to file to disk like so:

[[FBRequest requestForMyFriends] startWithCompletionHandler:^(FBRequestConnection *connection,
                                                                       NSDictionary *results,
                                                                       NSError *error)
{
if(!error){

NSDictionary* friends = results;

NSLog(@"Found %i friends", friends.count);

NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docDir = [paths objectAtIndex:0];
NSString* fileName = [docDir stringByAppendingPathComponent:@"userInfo.dat"];

if ([friends writeToFile:fileName atomically:YES]) {
    NSLog(@"Wrote friends file to disk!");
    sendFBEvent(FB_EVENT_DETAILS_FRIENDS, [fileName UTF8String]);
}
else{
    NSLog(@"Couldn't write friends details to disk!");
}

This works, but the file retrieved and written to disk is an XML file. I am almost certain that in a pervious version I was able to save the file in a JSON format, but I have since lost that revision and can't remember how I achieved it.

I'd appreciate it if someone could tell me how it is possible to save this file in the form of a JSON formatted file? I've done it before with a very simple method that isn't much different from my current method but I'll be damned if I can remember how.

Answer 1

Gah, awfully sorry but I was searching for Facebook related results when the answer was something native to Objective C:

Objective-C / iOS: Converting an array of objects to JSON string

Turns out you can use

NSData* jsonData = [NSJSONSerialization dataWithJSONObject:contactsToBeSynced options:NSJSONWritingPrettyPrinted error:&error];

To convert the array pulled from the request into JSON. Sorry about that, hope this is useful to someone in future at least!