Facebook login using RxSwift - facebook

Question

I'm trying to implement the following RxSwift example:
Login in with facebook in my application -> retrieve the user information -> retrieve user's profile photo.
I have these three functions and they must be executed in this order: requestAccess() -> fetchUserInformation() -> fetchUserPhoto()
func requestAccess() -> Observable<(ACAccount)> {
return create { observer -> Disposable in
let accountStore = ACAccountStore()
let accountType = accountStore.accountTypeWithAccountTypeIdentifier(ACAccountTypeIdentifierFacebook)
let dictionary: [NSObject : AnyObject] = [ACFacebookAppIdKey:"***APPID***", ACFacebookPermissionsKey:["public_profile", "email", "user_friends"]]
accountStore.requestAccessToAccountsWithType(accountType, options: dictionary) { granted, error in
if granted == false || error != nil {
sendError(observer, error ?? UnknownError)
} else {
let accounts = accountStore.accountsWithAccountType(accountType)
let account = accounts.last as! ACAccount
sendNext(observer, account)
sendCompleted(observer)
}
}
return AnonymousDisposable({})
}
}
func fetchUserInformation(account: ACAccount) -> Observable<User> {
return create { observer -> Disposable in
let url = NSURL(string: "https://graph.facebook.com/me")
let request = SLRequest(forServiceType: SLServiceTypeFacebook, requestMethod: .GET, URL: url, parameters: nil)
request.account = account
request.performRequestWithHandler { (data, response, error) -> Void in
if data == nil || response == nil {
sendError(observer, error ?? UnknownError)
} else {
let result: AnyObject? = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: nil)
let user = User()
user.updateInformationWithJSON(result! as! JSONObject)
sendNext(observer, user)
sendCompleted(observer)
}
}
return AnonymousDisposable({})
}
}
func fetchUserPhoto(user: User) -> Observable<AnyObject> {
return create { observer -> Disposable in
let url = NSURL(string: "https://graph.facebook.com/***myid***/picture")
let params = ["redirect":"false", "height":"200", "width":"200"]
let request = SLRequest(forServiceType: SLServiceTypeFacebook, requestMethod: .GET, URL: url, parameters: params)
request.account = SocialController.account
request.performRequestWithHandler { (data, response, error) -> Void in
if data == nil || response == nil {
sendError(observer, error ?? UnknownError)
} else {
let result: AnyObject? = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: nil)
sendNext(observer, result!)
sendCompleted(observer)
}
}
return AnonymousDisposable({})
}
}
I already tried to implement this flow but it doesn't feel right. What is the best way to solve this problem?
requestAccess()
>- subscribeNext { account in
fetchUserInformation(account)
>- map { user in return UserViewModel(model: user) }
>- subscribeNext { viewModel in self.viewModel = viewModel }
}

Answer 1

Have you tried using flatMap?
It's an equivalent to then in the JavaScript bluebird or Q world. The difference between map and flatMap is that flatMap must return an Observable<T> which will then be unwrapped in the following block/closure.
requestAccess()
>- flatMap{ account in
return fetchUserInformation(account)
}
>- map { user in
return UserViewModel(model:user)
}
>- subscribeNext { viewModel in
self.viewModel = viewModel
}
Tidbit #1: Consider using unowned self when referencing self to avoid a retain cycle.
Tidbit #2: These two are pretty much the same thing.
flatMap { return just("hello") }
>- subscribeNext{ greeting in println(greeting) }
map { return "hello" }
>- subscribeNext{ greeting in println(greeting) }

Answer 2

private
func requestFacebookAccess(_ viewController: UIViewController) -> Observable<LoginManagerLoginResult?> {
return Observable.create { observer -> Disposable in
let loginManager = LoginManager()
loginManager.logIn(permissions: ["public_profile", "email"], from: viewController, handler: { result, error in
observer.onNext(result)
observer.onCompleted()
})
return Disposables.create()
}
}