Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
FacebookAuth is for iOS app developers who need to support Facebook login but don't want to use the official SDK
//
// FacebookAuth.swift
// GitHub: ethanhuang13
// Twitter: @ethanhuang13
import AuthenticationServices
import SafariServices
/*
Updated:
Pointed out by [@hal_lee on Twitter](https://twitter.com/hal_lee/status/1259132680828043265?s=21) this approach violates [Facebook Platform Policy 8.2](https://developers.facebook.com/policy/) and might be contacted by them to stop doing it.
The best way to not using Facebook SDK is not to support Facebook Login at all.
I leave the code here and let you make the decision.
Original:
FacebookAuth is for iOS app developers who need to support Facebook login but don't want to use the official SDK.
iOS 11+ is required since it uses SFAuthenticationSession or ASWebAuthenticationSession.
You need to setup the client id in Facebook Developer console, see https://github.com/fullstackreact/react-native-oauth/issues/76#issuecomment-335902057
For more information, visit https://developers.facebook.com/docs/facebook-login/manually-build-a-login-flow/
*/
// MARK: Usage
/*
FacebookAuth.start(clientId: "12345678", scope: ["public_profile", "email"], window: UIApplication.shared.keyWindow) { result in
switch result {
case .success(let token):
print(token)
// TODO: Pass token to backend
case .failure(let error):
print(error.localizedDescription)
// TODO: Handle error
}
}
*/
// MARK: Implementation
enum FacebookAuth {
enum AuthError: String, Error, LocalizedError {
case invalidQuery
case noURL
case stateInconsistent
case noAccessToken
var errorDescription: String? { rawValue }
}
static func start(clientId: String, scope: [String], window: UIWindow?, completion: @escaping (Result<String, Error>) -> Void) {
let state = UUID().uuidString
var urlComponents = URLComponents()
urlComponents.scheme = "https"
urlComponents.host = "www.facebook.com"
urlComponents.path = "/v7.0/dialog/oauth"
urlComponents.queryItems = [
"client_id": clientId,
"response_type": "token",
"redirect_uri": "fb\(clientId)://authorize",
"state": state,
"scope": scope.joined(separator: ",")]
.map { URLQueryItem(name: $0.key, value: $0.value) }
guard let url = urlComponents.url else {
completion(.failure(AuthError.invalidQuery))
return
}
let callbackURLScheme = "fb\(clientId)"
var session: AuthenticationSession?
let completionHandler: (URL?, Error?) -> Void = { url, error in
session = nil
print("auth callback url: \(url?.absoluteString ?? "failed")")
if let error = error {
completion(.failure(error))
return
}
guard let url = url else {
completion(.failure(AuthError.noURL))
return
}
var urlComponents = URLComponents(url: url, resolvingAgainstBaseURL: false)
urlComponents?.query = url.fragment
guard let returnedState = urlComponents?.queryItems?.first(where: { $0.name == "state" })?.value,
returnedState == state else {
completion(.failure(AuthError.stateInconsistent))
return
}
guard let token = urlComponents?.queryItems?.first(where: { $0.name == "access_token" })?.value else {
completion(.failure(AuthError.noAccessToken))
return
}
completion(.success(token))
}
if #available(iOS 12.0, *) {
session = ASWebAuthenticationSession(url: url, callbackURLScheme: callbackURLScheme, completionHandler: completionHandler)
if #available(iOS 13.0, *) {
(session as? ASWebAuthenticationSession)?.presentationContextProvider = window
}
} else {
session = SFAuthenticationSession(url: url, callbackURLScheme: callbackURLScheme, completionHandler: completionHandler)
}
_ = session?.start()
}
}
// MARK: Extensions
protocol AuthenticationSession {
func start() -> Bool
}
extension SFAuthenticationSession: AuthenticationSession { }
@available(iOS 12.0, *)
extension ASWebAuthenticationSession: AuthenticationSession { }
extension UIWindow: ASWebAuthenticationPresentationContextProviding {
@available(iOS 13.0, *)
public func presentationAnchor(for session: ASWebAuthenticationSession) -> ASPresentationAnchor { self }
}
MIT License
Copyright (c) 2020 Ethan Huang
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
@ethanhuang13

This comment has been minimized.

Copy link
Owner Author

@ethanhuang13 ethanhuang13 commented May 9, 2020

By the way, I've got a lot of inspiration from my friend @yesleon https://gist.github.com/yesleon/904d8fe418a17467aada5b8661dba665

@ethanhuang13

This comment has been minimized.

Copy link
Owner Author

@ethanhuang13 ethanhuang13 commented May 9, 2020

LICENSE added. Use the code whatever you want. Thanks.

@ethanhuang13

This comment has been minimized.

Copy link
Owner Author

@ethanhuang13 ethanhuang13 commented May 9, 2020

Pointed out by @hal_lee on Twitter this approach violates Facebook Platform Policy 8.2 and might be contacted by Facebook to stop doing it.
The best way to not using Facebook SDK is not to support Facebook Login at all.
I leave the code here and let you make the decision.

@ethanhuang13

This comment has been minimized.

Copy link
Owner Author

@ethanhuang13 ethanhuang13 commented Jul 10, 2020

If you still need to use FBSDK but are considering building a "kill switch", you might want to check FacebookAutoInitEnabled in the official document for how not to auto init.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.