How to read RequestBody by PipeReader and return start position of stream to zero (Net core 6)

Question

I need access to RequestBody inside OnActionExecuting or OnActionExecuted filter, but I can not found concrete example how to use PipeReader to read full request body stream and return stream position to zero (in order to read request parameters by ControllerBase - if I read body OnActionExecuting or firstly return position to zero if I read in OnActionExecuting).

In my attribute Body always empty.

However, API parameters is present.

Or maybe there is another way to receive Request Body in Action Filter for ControllerBase?

Answer 1

From your description, I think you wanna get request body in multiple times in asp.net core. But in asp.net core, the request can not be read once it is consumed. If you want to read the request body multiple times, you need to set:

context.Request.EnableBuffering()

Then to read the body stream you could for example do this:

string bodyContent = new StreamReader(Request.Body).ReadToEnd();

On the safer side, set the Request.Body.Position reset to 0. That way any code later in the request lifecycle will find the request body in the state just like it hasn’t been read yet.

Request.Body.Position = 0;

So you can set this code in either OnActionExecuting or OnActionExecuted method.

public void OnActionExecuting(ActionExecutingContext context)
        {
            
            context.HttpContext.Request.EnableBuffering();
            string bodyContent = new StreamReader(context.HttpContext.Request.Body).ReadToEnd();
            context.HttpContext.Request.Body.Position = 0;
        }

But please note that, Model binding happens before action filter, So Model binding will consume request body first and you can not read it in your action filter, You need to custom model binding and Apply the above configuration to it.