[Feature Request] .WithAccessTokenSha256ToRefresh(string hash)

[rayluo]

MSAL client type

Confidential, Managed identity

Problem statement

Currently, MSAL provides only unconditional token refresh. We need to support precisely specifying an old token to be refreshed. Details described in Precise Token Cache Refresh proposal.

Proposed solution

A Minimal Viable Product (MVP) shall implement:

• Chapter 5 of the proposal above
  • ConfidentialClientApplication.AcquireTokenForClient().WithAccessTokenSha256ToRefresh(string hash)
  • ManagedIdentityClient.AcquireTokenForClient().WithAccessTokenToRefresh(string token)
• .WithClaim(...) behavior change described in Appendix 1 of the proposal above

Acceptance Tests

The following test cases are meant to be tested sequentially.

1. CCA

   1. Prepopulate the token cache of a CCA with a token token1.
   2. Test a new CCA.AcquireTokenForClient().WithAccessTokenSha256ToRefresh("mismatchingHash") should not trigger refresh.
   3. Test matching hash CCA.AcquireTokenForClient().WithAccessTokenSha256ToRefresh("hashOfToken1") should trigger refresh and obtain a new token token2.
   4. CCA.AcquireTokenForClient().WithAccessTokenSha256ToRefresh("hashOfToken1").WithClaims("..."). This is a client using old token1, with proper hash(token1), even with claims challenge, should NOT trigger refresh, because we can serve it with token2 in cache.

2. Managed Identity v1. All MSIv1 share same api surface, which will NOT be changed this time, but the behavior for Service Fabric shall be changed.

   1. Create a sf = ManagedIdentityClient(...) for Service Fabric. Prepopulate its token cache with a token token1.
   2. Test a new sf.AcquireToken().WithClaims("foo"). Assert the function call will bypass token cache and trigger a new token request with new parameters ...&api-version=2019-07-01-preview&token_sha256_to_refresh=theHash.
      Note that this .WithClaims(...) behavior is DIFFERENT than CCA's case 4, due to the fact that we currently choose to not introduce a .WithAccessTokenToRefresh() into MSI api.
   3. Test a new sf.AcquireToken().WithClaims("xxxxx...1KB payload"). Assert the function call will bypass token cache and trigger a new token request with new parameters ...&api-version=2019-07-01-preview&token_sha256_to_refresh=theHash.
   4. Redo the previous test cases for IMDS, App Service, etc., and assert that their token requests do NOT contain the new claims nor token_sha256_to_refresh behavior.
       

Alternatives

No response

[bgavrilMS]

I don't think API this would go on ManagedIdentityClient. We don't want to change the contract between app developers and SDK - they can just use "claims".

[rayluo]

I don't think API this would go on ManagedIdentityClient. We don't want to change the contract between app developers and SDK - they can just use "claims".

Correct. The earlier requirements on ManagedIdentityClient. ... .WithAccessTokenToRefresh(string token) has been crossed out from the "proposed solution" above, but test cases for Managed Identity still remain. Please help proofread them.