CustomProxy and best place to catch/intercept error, specifically when JWT token expires.

[richardbartley]

I have a Winforms application calling ASPNet Core hosted DataPortal with a mixed authentication model (AD authentication and good old-fashioned manual logins), and all working fine.

Am using a CustomProxy class, but I need/want a simple re-try pattern if any of my dataportal calls fail with an unauthorized exception when the token expires.

Where's the best place to centralize a check?

I'm looking at the custom proxy class and wondering if I override the base Fetch, Delete, etc methods.

public class CustomHttpProxy : HttpProxy
{
    private readonly string _jwtToken;

    public CustomHttpProxy(Csla.ApplicationContext applicationContext, HttpClient httpClient, HttpProxyOptions options, string jwtToken)
        : base(applicationContext, httpClient, options)
    {
        _jwtToken = jwtToken;
    }

    public override Task<DataPortalResult> Fetch(Type objectType, object criteria, DataPortalContext context, bool isSync)
    {
        **// some retry logic here if token expired?????**
        return base.Fetch(objectType, criteria, context, isSync);
    }

[rockfordlhotka]

I think that is correct. Rocky Get Outlook for Android<https://aka.ms/AAb9ysg>

…

________________________________ From: richardbartley ***@***.***> Sent: Monday, January 15, 2024 9:36:30 AM To: MarimerLLC/csla ***@***.***> Cc: Subscribed ***@***.***> Subject: [MarimerLLC/csla] CustomProxy and best place to catch/intercept error, specifically when JWT token expires. (Discussion #3653) I have a Winforms application calling ASPNet Core hosted DataPortal with AD authentication, and all working fine. Am using a CustomProxy class, but I need/want a simple re-try pattern if any of my dataportal calls fail with an unauthorized exception when the token expires. Where's the best place to centralize a check? I'm looking at the custom proxy class and wondering if I override the base Fetch, Delete, etc methods. public class CustomHttpProxy : HttpProxy { private readonly string _jwtToken; public CustomHttpProxy(Csla.ApplicationContext applicationContext, HttpClient httpClient, HttpProxyOptions options, string jwtToken) : base(applicationContext, httpClient, options) { _jwtToken = jwtToken; } public override Task<DataPortalResult> Fetch(Type objectType, object criteria, DataPortalContext context, bool isSync) { **// some retry logic here if token expired?????** return base.Fetch(objectType, criteria, context, isSync); } — Reply to this email directly, view it on GitHub<#3653>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AARZTTWXRYASHECRK7ZWNJLYOVLI5AVCNFSM6AAAAABB3RNKEGVHI2DSMVQWIX3LMV43ERDJONRXK43TNFXW4OZWGA3TQMZUGM>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[StefanOssendorf]

Another way would be to implement a DelegatingHandler and configure the the default HttpClient (configured via services.AddHttpClient() iirc) to use it. So it's automatically used for every HttpClient request made by the default HttpClient.

[richardbartley]

In the end, I found my my scenario was to follow Stefans advice and I configured a policy handler with my desired retry logic.

services.AddHttpClient<HttpClient>().AddPolicyHandler(GetRetryPolicy());

The Polly policies can be configured in multiple ways.

For example,

private static IAsyncPolicy<HttpResponseMessage> GetRetryPolicy() => HttpPolicyExtensions
     .HandleTransientHttpError()
     .OrResult(msg => msg.StatusCode == System.Net.HttpStatusCode.Unauthorized)
     .RetryAsync(3, async (response, retryCount, context) =>
     {
        // add your retry logic here, like refreshing the token and making 
        // it available on the subsequent http/dataportal request
     });