NullReferenceException when run proxy in .Net core 2.2

[moustafa11911]

Hello, I am getting this exception when run proxy

System.NullReferenceException: Object reference not set to an instance of an object. at AspNetCore.Proxy.Basic.GetEndpointFromComputerAsync(HttpContext context, EndpointComputerToValueTask computer) at AspNetCore.Proxy.HttpExtensions.ExecuteHttpProxyOperationAsync(HttpContext context, HttpProxy httpProxy) at AspNetCore.Proxy.Basic.ExecuteProxyOperationAsync(HttpContext context, Proxy proxy) at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ProcessRequests[TContext](IHttpApplication1 application)`

the proxy code

app.RunProxy(proxy =>
proxy.UseHttp((context, args) =>
{
    if (context.Request.Path.StartsWithSegments("/api/yy"))
          return Configuration["AppSettings:ApiUrl"];
}));

I install latest package V 4.2.0 on my project which run using .NetCore 2.2 waiting your help as this is a showstopper issue. Thanks.

[twitchax]

This is likely caused by the fact that you need to return a string in the else clause. Can you try returning a string in the else clause?

[moustafa11911]

thanks for reply, I use a default string at the end and the same issue exists

app.RunProxy(proxy =>
proxy.UseHttp((context, args) =>
{
    if (context.Request.Path.StartsWithSegments("/api/yy"))
          return Configuration["AppSettings:ApiUrl"];

    return Configuration["AppSettings:DefultApiUrl"];
}));

[twitchax]

Interesting. Can you try debug-printing those strings before you return them? Is it possible the Configuration is empty?

[moustafa11911]

I checked the configuration and it is as the following

Configuration["AppSettings:ApiUrl"] => https://localhost:5001 Configuration["AppSettings:DefultApiUrl"] => https://localhost:3001

[twitchax]

Ok, thanks!

Did you print those values from within that closure? Basically, I want to know if the code inside that closure ever gets hit. If it does, then something along context.Request.Path is null.

If it doesn't, then it is clear the problem is here. Which means that, somehow, context.GetRouteData().Values is null.

[twitchax]

It looks like GetRouteData() can be null, so that may be the culprit. I will push a patch, and you can try it out!

[twitchax]

Can you please try the updated package?

[moustafa11911]

Ok, will try it now

[moustafa11911]

Fixed now, thanks a lot for your great support.