FBSession+RACExtension

FBSession+RACExtension.h

#import <Facebook-iOS-SDK/FacebookSDK/FBSession.h>

@class RACSignal;

@interface FBSession (RACExtension)

+ (FBSession *)rac_activeSession:(BOOL)cachedOnly;

+ (void)rac_reset;

+ (RACSignal *)rac_openedSessionSignal;
+ (RACSignal *)rac_openedSessionSignal:(BOOL)forced;

- (RACSignal *)rac_openSignal;
- (RACSignal *)rac_openSignal:(FBSessionLoginBehavior)behavior;

@end

FBSession+RACExtension.m

#import "FBSession+RACExtension.h"
#import "FBSession+Internal.h"

#import <ReactiveCocoa/ReactiveCocoa/ReactiveCocoa.h>

@implementation FBSession (RACExtension)

#pragma mark -

+ (FBSession *)rac_activeSession:(BOOL)cachedOnly {
    // reopen from local cache
    if ([FBSession openActiveSessionWithAllowLoginUI:NO] && [FBSession activeSessionIfExists]) {
        return [FBSession activeSession];
    } else if (!cachedOnly) {
        // create new one
        FBSession *session = [[FBSession alloc] initWithPermissions:@[@"email", @"public_profile"]];
        [FBSession setActiveSession:session];
        return session;
    }

    return nil;
}

#pragma mark - Open Session

- (RACSignal *)rac_openSignal {
	return [self rac_openSignal:FBSessionLoginBehaviorUseSystemAccountIfPresent];
}

- (RACSignal *)rac_openSignal:(FBSessionLoginBehavior)behavior {
	if (self.isOpen) return [RACSignal return:self];

	return [[[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
		[self openWithBehavior:behavior completionHandler:^(FBSession *session, FBSessionState status, NSError *error) {
			if (status == FBSessionStateClosedLoginFailed || status == FBSessionStateClosed || status == FBSessionStateCreatedOpening) {
				[session closeAndClearTokenInformation];

				[subscriber sendError:error];
			} else {
				[subscriber sendNext:session];
				[subscriber sendCompleted];
			}
		}];

		return [RACDisposable disposableWithBlock:^{
			[self setStateChangeHandler:NULL];
		}];
	}] deliverOn:[RACScheduler mainThreadScheduler]] replayLazily];
}

#pragma mark - Opened Session

+ (RACSignal *)rac_openedSessionSignal {
	return [self rac_openedSessionSignal:YES];
}

+ (RACSignal *)rac_openedSessionSignal:(BOOL)forced {
	return [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
        [subscriber sendNext:[FBSession rac_activeSession:!forced]];
		[subscriber sendCompleted];

		return nil;
	}] flattenMap:^RACStream *(FBSession *session) {
		if (!session) return [RACSignal return:nil];

		return [session rac_openSignal:FBSessionLoginBehaviorUseSystemAccountIfPresent];
	}];
}

#pragma mark - Reset

+ (void)rac_reset {
    [[FBSession rac_activeSession:NO] closeAndClearTokenInformation];
	[FBSession setActiveSession:nil];
}

@end