Every app needs authentication and authorization. Logto is an Auth0 alternative designed for modern apps and SaaS products.
In this article, we will go through the steps to quickly build the Google sign-in experience (user authentication) with iOS Swift and Logto.
Prerequisites
- A running Logto instance. Check out the introduction page to get started.
- Basic knowledge of iOS Swift.
- A usable Google account.
Create an application in Logto
In you browser, open a new tab and enter the link of Logto Admin Console.
Once the page is loaded, in the "Get Started" section click the View all
link to open the application framework list page.
Choose your application type
In the opening modal, scroll to the "Native app" section or filter all the available " Native app" frameworks using the quick filter checkboxes on the left.
Click the "iOS(Swift)" framework card to start creating your application.
Enter application name
Enter the application name, e.g., "Bookstore," and click "Create application."
🎉 Ta-da! You just created your first application in Logto. You'll see a congrats page which includes a detailed integration guide. Follow the guide to see what the experience will be in your application.
Integrate Logto SDK
Add Logto SDK as a dependency
Use the following URL to add Logto SDK as a dependency in Swift Package Manager.
https://github.com/logto-io/swift.git
Since Xcode 11, you can directly import a Swift package w/o any additional tool.
We do not support Carthage and CocoaPods at the time due to some technical issues.
Carthage
Carthage needs a xcodeproj
file to build, but swift package generate-xcodeproj
will report a failure since we are using binary targets
for native social plugins. We will try to find a workaround later.
CocoaPods
CocoaPods does not support local dependency and monorepo, thus it's hard to create a .podspec
for this repo.
Init LogtoClient
Initialize the client by creating a LogtoClient
instance with a LogtoConfig
object.
import Logto
import LogtoClient
let config = try? LogtoConfig(
endpoint: "<your-logto-endpoint>", // E.g. http://localhost:3001
appId: "<your-app-id>"
)
let client = LogtoClient(useConfig: config)
By default, we store credentials like ID Token and Refresh Token in the Keychain. Thus the user doesn't need to sign in again when he returns.
To turn off this behavior, set usingPersistStorage
to false
:
let config = try? LogtoConfig(
// ...
usingPersistStorage: false
)
Sign in
Before we dive into the details, here's a quick overview of the end-user experience. The sign-in process can be simplified as follows:
- Your app invokes the sign-in method.
- The user is redirected to the Logto sign-in page. For native apps, the system browser is opened.
- The user signs in and is redirected back to your app (configured as the redirect URI).
Regarding redirect-based sign-in
- This authentication process follows the OpenID Connect (OIDC) protocol, and Logto enforces strict security measures to protect user sign-in.
- If you have multiple apps, you can use the same identity provider (Logto). Once the user signs in to one app, Logto will automatically complete the sign-in process when the user accesses another app.
To learn more about the rationale and benefits of redirect-based sign-in, see Logto sign-in experience explained.
Configure redirect URI
Let's switch to the Application details page of Logto Console. Add a Redirect URI io.logto://callback
and click "Save changes".
The Redirect URI in iOS SDK is only for internal use. There's NO NEED to add a Custom URL Scheme until a connector asks.
Sign-in and sign-out
Before calling .signInWithBrowser(redirectUri:)
, make sure you have correctly configured Redirect URI
in Admin Console.
You can use client.signInWithBrowser(redirectUri:)
to sign in the user and client.signOut()
to sign out the user.
For example, in a SwiftUI app:
struct ContentView: View {
@State var isAuthenticated: Bool
init() {
isAuthenticated = client.isAuthenticated
}
var body: some View {
VStack {
if isAuthenticated {
Button("Sign Out") {
Task { [self] in
await client.signOut()
isAuthenticated = false
}
}
} else {
Button("Sign In") {
Task { [self] in
do {
try await client.signInWithBrowser(redirectUri: "${
props.redirectUris[0] ?? 'io.logto://callback'
}")
isAuthenticated = true
} catch let error as LogtoClientErrors.SignIn {
// error occured during sign in
} catch {
// other errors
}
}
}
}
}
}
}
Open your iOS app to test if the integration works. When you click the "Sign In" button, the page should be redirected to a Logto sign-in page, and you should be able to create a new account by entering username and password and complete the sign-in process.
Add Google connector
To add a social connector, go to the "Connector" tab in the Admin Console, then click on "Social connectors". From there, click "Add social connector".
In the openning modal, select "Google" and click "Next".
On the next page, you will see a two-column layout with the README content on the left and configuration on the right.
Feel free to follow the README file in place or read the following section to complete the configuration process. If you follow the in-place guide, you can skip the next section.
Set up Google OAuth app
Set up a project in the Google API Console
- Visit the Google API Console and sign in with your Google account.
- Click the Select a project button on the top menu bar, and click the New Project button to create a project.
- In your newly created project, click the APIs & Services to enter the APIs & Services menu.
Configure your consent screen
- On the left APIs & Services menu, click the OAuth consent screen button.
- Choose the User Type you want, and click the Create button. (Note: If you select External as your User Type, you will need to add test users later.)
Now you will be on the Edit app registration page.
Config OAuth consent screen
- Follow the instructions to fill out the OAuth consent screen form.
- Click SAVE AND CONTINUE to continue.
Config scopes
- Click ADD OR REMOVE SCOPES and select
../auth/userinfo.email
,../auth/userinfo.profile
andopenid
in the popup drawer, and click UPDATE to finish. - Fill out the form as you need.
- Click SAVE AND CONTINUE to continue.
Add test users (External user type only)
- Click ADD USERS and add test users to allow these users to access your application while testing.
- Click SAVE AND CONTINUE to continue.
Now you should have the Google OAuth 2.0 consent screen configured.
Obtain OAuth 2.0 credentials
- On the left APIs & Services menu, click the Credentials button.
- On the Credentials page, click the + CREATE CREDENTIALS button on the top menu bar, and select OAuth client ID.
- On the Create OAuth client ID page, select Web application as the application type.
- Fill out the basic information for your application.
- Click + Add URI to add an authorized domain to the Authorized JavaScript origins section. This is the domain that your logto authorization page will be served from. In our case, this will be
${your_logto_origin}
. e.g.https://logto.dev
. - Click + Add URI in the **Authorized redirect URIs** section to set up the **Authorized redirect URIs**, which redirect the user to the application after logging in. In our case, this will be
${your_logto_endpoint}/callback/${connector_id}
. e.g.https://logto.dev/callback/${connector_id}
. Theconnector_id
can be found on the top bar of the Logto Admin Console connector details page. - Click Create to finish and then you will get the Client ID and Client Secret.
References
Config types
Name | Type |
---|---|
clientId | string |
clientSecret | string |
Google developer docs
Google Identity: Setting up OAuth 2.0
Save your configuration
Double check you have filled out necessary values in the Logto connector configuration area. Click "Save and Done" (or "Save changes") and the Google connector should be available now.
Enable Google connector in Sign-in Experience
Switch to the "Sign-in experience" tab, then click the "Sign-up and sign-in" tab.
If it's the first time you enter the tab, you will see a quick introduction about Sign-in Experience and its basic configuration.
Select "None" for the "Sign-up identifier" to provide minimum sign-up effort for Google sign-in, which may increase your conversion rate.
In the "Social sign-in" section, add "Add Social Connector" and choose "Google". Then you should be able to see a button with text "Continue with Google" in the preview section.
Finally, click "Save changes" on the bottom right corner.
Testing and Validation
Return to your iOS Swift app. You should now be able to sign in with Google. Enjoy!
Further readings
Protect your API For native and single page apps, you'll need to call one or more API endpoints to retrieve and update data.
Learn more about identifying who's who and keeping your API secure.
User management We know you care about user management and activities, as we also do.
Learn more about how to know your users and see the figures like DAU and MAU graphically.
Localization From one regional business to a global corporate, the willingness to offer the best user experience won't change.
You can change current language phrases or add a new language without friction.
Customer IAM series Our serial blog posts about Customer (or Consumer) Identity and Access Management, from 101 to advanced topics and beyond.