You can let your users authenticate with Firebase using their Twitter accounts
by integrating Twitter authentication into your app.
Before you begin
- Add Firebase to your C++ project
.
- In the
Firebase console
, open the
Auth
section.
- On the
Sign in method
tab, enable the
Twitter
provider.
- Add the
API key
and
API secret
from that provider's developer console to the
provider configuration:
- Register your app
as a developer application on Twitter and get your app's OAuth
API key
and
API secret
.
- Make sure your Firebase
OAuth redirect URI
(e.g.
my-app-12345.firebaseapp.com/__/auth/handler
)
is set as your
Authorization callback URL
in your app's settings page on your
Twitter app's config
.
- Click
Save
.
Access the
firebase::auth::Auth
class
The
Auth
class is the gateway for all API calls.
- Add the Auth and App header files:
#include "firebase/app.h"
#include "firebase/auth.h"
- In your initialization code, create a
firebase::App
class.
#if defined(__ANDROID__)
firebase::App* app =
firebase::App::Create(firebase::AppOptions(), my_jni_env, my_activity);
#else
firebase::App* app = firebase::App::Create(firebase::AppOptions());
#endif // defined(__ANDROID__)
- Acquire the
firebase::auth::Auth
class for your
firebase::App
.
There is a one-to-one mapping between
App
and
Auth
.
firebase::auth::Auth* auth = firebase::auth::Auth::GetAuth(app);
Authenticate with Firebase
- Follow the
Sign in with Twitter
documentation to get an OAuth access token and an OAuth secret.
- After a user successfully signs in, exchange the token and secret for a
Firebase credential, and authenticate with Firebase using the Firebase
credential:
firebase::auth::Credential credential =
firebase::auth::TwitterAuthProvider::GetCredential(token, secret);
firebase::Future<firebase::auth::AuthResult> result =
auth->SignInAndRetrieveDataWithCredential(credential);
- If your program has an update loop that runs regularly (say at 30 or 60
times per second), you can check the results once per update with
Auth::SignInAndRetrieveDataWithCredentialLastResult
:
firebase::Future<firebase::auth::AuthResult> result =
auth->SignInAndRetrieveDataWithCredentialLastResult();
if (result.status() == firebase::kFutureStatusComplete) {
if (result.error() == firebase::auth::kAuthErrorNone) {
firebase::auth::AuthResult auth_result = *result.result();
printf("Sign in succeeded for `%s`\n",
auth_result.user.display_name().c_str());
} else {
printf("Sign in failed with error '%s'\n", result.error_message());
}
}
Or, if your program is event driven, you may prefer to
register a callback on the
Future
.
Register a callback on a Future
Some programs have
Update
functions that are called 30 or 60 times per second.
For example, many games follow this model. These programs can call the
LastResult
functions to poll asynchronous calls.
However, if your program is event driven, you may prefer to register callback functions.
A callback function is called upon completion of the Future.
void OnCreateCallback(const firebase::Future<firebase::auth::User*>& result,
void* user_data) {
// The callback is called when the Future enters the `complete` state.
assert(result.status() == firebase::kFutureStatusComplete);
// Use `user_data` to pass-in program context, if you like.
MyProgramContext* program_context = static_cast<MyProgramContext*>(user_data);
// Important to handle both success and failure situations.
if (result.error() == firebase::auth::kAuthErrorNone) {
firebase::auth::User* user = *result.result();
printf("Create user succeeded for email %s\n", user->email().c_str());
// Perform other actions on User, if you like.
firebase::auth::User::UserProfile profile;
profile.display_name = program_context->display_name;
user->UpdateUserProfile(profile);
} else {
printf("Created user failed with error '%s'\n", result.error_message());
}
}
void CreateUser(firebase::auth::Auth* auth) {
// Callbacks work the same for any firebase::Future.
firebase::Future<firebase::auth::AuthResult> result =
auth->CreateUserWithEmailAndPasswordLastResult();
// `&my_program_context` is passed verbatim to OnCreateCallback().
result.OnCompletion(OnCreateCallback, &my_program_context);
}
The callback function can also be a lambda, if you prefer.
void CreateUserUsingLambda(firebase::auth::Auth* auth) {
// Callbacks work the same for any firebase::Future.
firebase::Future<firebase::auth::AuthResult> result =
auth->CreateUserWithEmailAndPasswordLastResult();
// The lambda has the same signature as the callback function.
result.OnCompletion(
[](const firebase::Future<firebase::auth::User*>& result,
void* user_data) {
// `user_data` is the same as &my_program_context, below.
// Note that we can't capture this value in the [] because std::function
// is not supported by our minimum compiler spec (which is pre C++11).
MyProgramContext* program_context =
static_cast<MyProgramContext*>(user_data);
// Process create user result...
(void)program_context;
},
&my_program_context);
}
Next steps
After a user signs in for the first time, a new user account is created and
linked to the credentials—that is, the user name and password, phone
number, or auth provider information—the user signed in with. This new
account is stored as part of your Firebase project, and can be used to identify
a user across every app in your project, regardless of how the user signs in.
-
In your apps, you can get the user's basic profile information from the
firebase::auth::User
object:
firebase::auth::User user = auth->current_user();
if (user.is_valid()) {
std::string name = user.display_name();
std::string email = user.email();
std::string photo_url = user.photo_url();
// The user's ID, unique to the Firebase project.
// Do NOT use this value to authenticate with your backend server,
// if you have one. Use firebase::auth::User::Token() instead.
std::string uid = user.uid();
}
In your Firebase Realtime Database and Cloud Storage
Security Rules
, you can
get the signed-in user's unique user ID from the
auth
variable,
and use it to control what data a user can access.
You can allow users to sign in to your app using multiple authentication
providers by
linking auth provider credentials to an
existing user account.
To sign out a user, call
SignOut()
:
auth->SignOut();