Replacing Invoke-WebRequest with HttpClient

I’ve written before about how frustrating the Error handling for Invoke-WebRequest and Invoke-RestMethod can be. But, there is another way to make web requests which will never update the global $Error object: write your own wrapper around HttpClient.

This method is much much more complicated than using Invoke-WebRequest, Invoke-RestMethod, or even Invoke-WebServiceProxy. But, it will give you complete control over the request and the response. And as a nice side effect, it’s cross platform compatible (runs on linux and windows).

Below is an example use of HttpClient to call Apigee’s OAuth Login endpoint.

(PS. The idea for using an HttpClient came from David Carroll’s PoShDynDnsApi powershell module. Which works with two implementations that use HttpClient (.NET Core and .NET Full Framework). The reason for two implementations is that DynDns requires one of their calls to perform a non-standard GET request with a body. Microsoft’s HttpClient implementation is pretty strict about following the rules and does not allow a body to be sent in GET requests. So, he had to use reflection to inject a body into his request. Each version of .NET had a different internal class structure that had to be set differently. It’s a pretty amazing work around.)