Tutorial: Prepare your iOS (Swift) app for authentication

Статия
06/28/2024

This is the second tutorial in the tutorial series that demonstrates how to add Microsoft Authentication Library (MSAL) for iOS and macOS to your iOS Swift app.

In this tutorial, you'll;

Add the MSAL framework to an iOS (Swift) app.
Create SDK instance.

Prerequisites

Xcode.
If you haven't already, follow the instructions in Tutorial: Register and configure iOS (Swift) mobile app and register an app in your external tenant. Make sure you complete the following steps:
- Register an application.
- Add a platform redirect URL.
- Enable public client flow.
- Delegated permission to Microsoft Graph.
iOS (Swift) project.

Add the MSAL framework to an iOS (Swift) app

The MSAL authentication SDK is used for integrating authentication into your apps using standard OAuth2 and OpenID Connect. It allows you to sign in users or apps with Microsoft identities. To add MSAL to your iOS (Swift) project, follow these steps:

Open your iOS project in Xcode.
Select Add Package Dependencies... from the File menu.
Enter https://github.com/AzureAD/microsoft-authentication-library-for-objc as the Package URL and choose Add Package

Update the Bundle Identifier

In Apple ecosystem, a Bundle Identifier is a unique identifier for an application. To update the Bundle Identifier in your project, follow these steps:

Open the project settings. In the Identity section, enter the Bundle Identifier.
Right-click Info.plist and select Open As > Source Code.

Under the dict root node, replace Enter_the_bundle_Id_Here with the Bundle Id that you used in the portal. Notice the msauth. prefix in the string.

<key>CFBundleURLTypes</key>
<array>
   <dict>
      <key>CFBundleURLSchemes</key>
      <array>
         <string>msauth.Enter_the_Bundle_Id_Here</string>
      </array>
   </dict>
</array>

Create SDK instance

To create MSAL instance in your project, follow these steps:

Import the MSAL library into your view controller by adding import MSAL at the top of your ViewController class.
Add an applicationContext member variable to your ViewController class by adding the following code just before the viewDidLoad() function:
```
var applicationContext : MSALPublicClientApplication?
var webViewParamaters : MSALWebviewParameters?
```
The code declares two variables: applicationContext, which stores an instance of MSALPublicClientApplication, and webViewParameters, which stores an instance of MSALWebviewParameters. MSALPublicClientApplication is a class provided by the MSAL for handling public client applications. The MSALWebviewParameters is a class provided by MSAL that defines parameters for configuring the web view used during the authentication process.
Add the following code to the view viewDidLoad() function:
```
 do {
        try self.initMSAL()
    } catch let error {
        self.updateLogging(text: "Unable to create Application Context \(error)")
    }
```
The code attempts to initialize MSAL, handling any errors that occur during the process. If an error occurs, it updates the logging with the details of the error.

Add the following code that creates initMSAL() function, which initializes MSAL:

    func initMSAL() throws {

    guard let authorityURL = URL(string: Configuration.kAuthority) else {
        self.updateLogging(text: "Unable to create authority URL")
        return
    }

    let authority = try MSALCIAMAuthority(url: authorityURL)

    let msalConfiguration = MSALPublicClientApplicationConfig(clientId: Configuration.kClientID,
                                                              redirectUri: Configuration.kRedirectUri,
                                                              authority: authority)
    self.applicationContext = try MSALPublicClientApplication(configuration: msalConfiguration)
}

This code initializes the MSAL for iOS. It first attempts to create a URL for the authority using the provided Configuration.kAuthority string. If successful, it creates an MSAL authority object based on that URL. Then, it configures the MSALPublicClientApplication with the given client ID, redirect URI, and authority. If all configurations are set up correctly, it initializes the application context with the configured MSALPublicClientApplication. If any errors occur during the process, it throws an error.

Create Configuration.swift file and add the following configurations:
```
import Foundation

@objcMembers
class Configuration {
    static let kTenantSubdomain = "Enter_the_Tenant_Subdomain_Here"

    // Update the below to your client ID you received in the portal.
    static let kClientID = "Enter_the_Application_Id_Here"
    static let kRedirectUri = "Enter_the_Redirect_URI_Here"
    static let kProtectedAPIEndpoint = "Enter_the_Protected_API_Full_URL_Here"
    static let kScopes = ["Enter_the_Protected_API_Scopes_Here"]

    static let kAuthority = "https://\(kTenantSubdomain).ciamlogin.com"

}
```
This Swift configuration code defines a class named Configuration and is marked with @objcMembers. It includes static constants for various configuration parameters related to an authentication setup. These parameters include the tenant subdomain, client ID, redirect URI, protected API endpoint, and scopes. These configuration constants should be updated with appropriate values specific to the application's setup.

Find the placeholder:
- Enter_the_Application_Id_Here and replace it with the Application (client) ID of the app you registered earlier.
- Enter_the_Redirect_URI_Here and replace it with the value of kRedirectUri in the MSAL configuration file you downloaded earlier when you added the platform redirect URL.
- Enter_the_Protected_API_Scopes_Here and replace it with the scopes recorded earlier. If you haven't recorded any scopes, you can leave this scope list empty.
- Enter_the_Tenant_Subdomain_Here and replace it with the Directory (tenant) subdomain. For example, if your tenant primary domain is contoso.onmicrosoft.com, use contoso. If you don't know your tenant subdomain, learn how to read your tenant details.

Use custom URL domain (Optional)

Use a custom domain to fully brand the authentication URL. From a user perspective, users remain on your domain during the authentication process, rather than being redirected to ciamlogin.com domain name.

Use the following steps to use a custom domain:

Use the steps in Enable custom URL domains for apps in external tenants to enable custom URL domain for your external tenant.
Open Configuration.swift file:
1. Update the value of the kAuthority property to https://Enter_the_Custom_Domain_Here/Enter_the_Tenant_ID_Here. Replace Enter_the_Custom_Domain_Here with your custom URL domain and Enter_the_Tenant_ID_Here with your tenant ID. If you don't have your tenant ID, learn how to read your tenant details.

After you make the changes to your Configuration.swift file, if your custom URL domain is login.contoso.com, and your tenant ID is aaaabbbb-0000-cccc-1111-dddd2222eeee, then your file should look similar to the following snippet:

    import Foundation

    @objcMembers
    class Configuration {
        static let kTenantSubdomain = "login.contoso.com"
        
        // Update the below to your client ID you received in the portal.
        static let kClientID = "Enter_the_Application_Id_Here"
        static let kRedirectUri = "Enter_the_Redirect_URI_Here"
        static let kProtectedAPIEndpoint = "Enter_the_Protected_API_Full_URL_Here"
        static let kScopes = ["Enter_the_Protected_API_Scopes_Here"]
        
        static let kAuthority = "https://\(kTenantSubdomain)/aaaabbbb-0000-cccc-1111-dddd2222eeee"
    
    }

Next steps

Tutorial: Sign in users in iOS (Swift) mobile app

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