login method

@override Future<LoginResult> login({ List<String> permissions = const ['email', 'public_profile'], LoginBehavior loginBehavior = LoginBehavior.dialogOnly, LoginTracking loginTracking = LoginTracking.enabled, String? nonce, })

make a login request using the facebook SDK

permissions permissions like "email","public_profile"

loginBehavior (only Android) use this param to set the UI for the authentication, like webview, native app, or a dialog.

Implementation

@override
Future<LoginResult> login({
  List<String> permissions = const ['email', 'public_profile'],
  LoginBehavior loginBehavior = LoginBehavior.dialogOnly,
  LoginTracking loginTracking = LoginTracking.enabled,
  String? nonce,
}) async {
  assert(
    _appId.isNotEmpty,
    'On desktop before call login() you must call to desktopInitialize(...)',
  );

  final signInURL = Uri.parse(
    'https://www.facebook.com/$_version/dialog/oauth',
  );
  const redirectURL = 'https://www.facebook.com/connect/login_success.html';

  final signInUri = Uri(
    scheme: signInURL.scheme,
    host: signInURL.host,
    path: signInURL.path,
    queryParameters: {
      'client_id': _appId,
      'redirect_uri': redirectURL,
      'response_type': 'token,granted_scopes',
      'scope': permissions.join(','),
      'state': _generateNonce(),
    },
  );

  final callbackUrl = await PlatformChannel().signIn(
    signInUri.toString(),
    redirectURL,
  );

  if (callbackUrl != null) {
    final fragment = Uri.parse(callbackUrl).fragment;
    final arguments = Uri.splitQueryString(fragment);

    String? token = arguments['long_lived_token'];
    bool isLoginLiveToken = token != null;

    late final DateTime expiresIn;

    if (!isLoginLiveToken) {
      token = arguments['access_token']!;
      expiresIn = DateTime.now().add(
        Duration(
          seconds: int.parse(arguments['expires_in']!),
        ),
      );
    } else {
      expiresIn = DateTime.now().add(
        const Duration(days: 59),
      );
    }

    final grantedScopes = arguments['granted_scopes']!.split(',');
    final deniedScopes = arguments['denied_scopes']!.split(',');

    final response = await _httpClient.get(
      Uri.parse('https://graph.facebook.com/me?access_token=$token'),
    );
    if (response.statusCode == 200) {
      final userData = jsonDecode(response.body);

      final accessToken = ClassicToken(
        declinedPermissions: deniedScopes,
        grantedPermissions: grantedScopes,
        userId: userData['id'],
        expires: expiresIn,
        tokenString: token,
        applicationId: _appId,
      );

      await _secureStorage.delete(key: _facebookAccessTokenKey);

      await _secureStorage.write(
        key: _facebookAccessTokenKey,
        value: jsonEncode(
          accessToken.toJson(),
        ),
      );

      return LoginResult(
        status: LoginStatus.success,
        accessToken: accessToken,
      );
    }

    return LoginResult(
      status: LoginStatus.failed,
      message: 'User info could not be get it',
    );
  }

  return LoginResult(status: LoginStatus.cancelled);
}