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Request custom claims using MSAL for iOS and macOS

  • Artikel

OpenID Connect allows you to optionally request the return of individual claims from the UserInfo Endpoint and/or in the ID Token. A claims request is represented as a JSON object that contains a list of requested claims. See OpenID Connect Core 1.0 for more details.

The Microsoft Authentication Library (MSAL) for iOS and macOS allows requesting specific claims in both interactive and silent token acquisition scenarios. It does so through the claimsRequest parameter.

There are multiple scenarios where this is needed. For example:

  • Requesting claims outside of the standard set for your application.
  • Requesting specific combinations of the standard claims that cannot be specified using scopes for your application. For example, if an access token gets rejected because of missing claims, the application can request the missing claims using MSAL.

Note

MSAL bypasses the access token cache whenever a claims request is specified. It's important to only provide claimsRequest parameter when additional claims are needed (as opposed to always providing same claimsRequest parameter in each MSAL API call).

claimsRequest can be specified in MSALSilentTokenParameters and MSALInteractiveTokenParameters:

/*!
 MSALTokenParameters is the base abstract class for all types of token parameters (silent and interactive).
 */
@interface MSALTokenParameters : NSObject

/*!
 The claims parameter that needs to be sent to authorization or token endpoint.
 If claims parameter is passed in silent flow, access token will be skipped and refresh token will be tried.
 */
@property (nonatomic, nullable) MSALClaimsRequest *claimsRequest;

@end

MSALClaimsRequest can be constructed from an NSString representation of JSON Claims request.

Objective-C:

NSError *claimsError = nil;
MSALClaimsRequest *request = [[MSALClaimsRequest alloc] initWithJsonString:@"{\"id_token\":{\"auth_time\":{\"essential\":true},\"acr\":{\"values\":[\"urn:mace:incommon:iap:silver\"]}}}" error:&claimsError];

Swift:

var requestError: NSError? = nil
let request = MSALClaimsRequest(jsonString: "{\"id_token\":{\"auth_time\":{\"essential\":true},\"acr\":{\"values\":[\"urn:mace:incommon:iap:silver\"]}}}",
                                        error: &requestError)

It can also be modified by requesting additional specific claims:

Objective-C:

MSALIndividualClaimRequest *individualClaimRequest = [[MSALIndividualClaimRequest alloc] initWithName:@"custom_claim"];
individualClaimRequest.additionalInfo = [MSALIndividualClaimRequestAdditionalInfo new];
individualClaimRequest.additionalInfo.essential = @1;
individualClaimRequest.additionalInfo.value = @"myvalue";
[request requestClaim:individualClaimRequest forTarget:MSALClaimsRequestTargetIdToken error:&claimsError];

Swift:

let individualClaimRequest = MSALIndividualClaimRequest(name: "custom-claim")
let additionalInfo = MSALIndividualClaimRequestAdditionalInfo()
additionalInfo.essential = 1
additionalInfo.value = "myvalue"
individualClaimRequest.additionalInfo = additionalInfo
do {
  try request.requestClaim(individualClaimRequest, for: .idToken)
} catch let error as NSError {
  // handle error here  
}

MSALClaimsRequest should be then set in the token parameters and provided to one of MSAL token acquisitions APIs:

Objective-C:

MSALPublicClientApplication *application = ...;
MSALWebviewParameters *webParameters = ...;

MSALInteractiveTokenParameters *parameters = [[MSALInteractiveTokenParameters alloc] initWithScopes:@[@"user.read"]
                                                                                  webviewParameters:webParameters];
parameters.claimsRequest = request;
    
[application acquireTokenWithParameters:parameters completionBlock:completionBlock];

Swift:

let application: MSALPublicClientApplication!
let webParameters: MSALWebviewParameters!
        
let parameters = MSALInteractiveTokenParameters(scopes: ["user.read"], webviewParameters: webParameters)
parameters.claimsRequest = request
        
application.acquireToken(with: parameters) { (result: MSALResult?, error: Error?) in            ...