Reading Request body in .net core 3.1 - .net-core-3.1

Question

I am trying to read request body in ActionFilter but having some strange errors.
What I tried so far:
Copying request body to memory stream
context.HttpContext.Request.Body.CopyTo(memoryStream)
Throws an error that only async operations are supported.
Copying request body to memory stream async
context.HttpContext.Request.Body.CopyToAsync(memoryStream).Wait()
Copies 0 bytes
Using BodyReader:
context.HttpContext.Request.BodyReader.AsStream(true).CopyToAsync(requestBody).Wait();
throws ArgumentOutOfRange exception 'Specified argument was out of the range of valid values. (Parameter 'start')'
I am using .net core 3.1

Answer 1

I had to convert my code to MiddleWare which is able to deal with Body stream:
MIddleware ccaptures request and put it to service.
Action filter access service and decides what to do with it.
Here is a code of middleware
public class RequestReaderMiddleWare
{
private readonly RequestDelegate _next;
public RequestReaderMiddleWare(RequestDelegate next)
{
_next = next;
}
public virtual async Task Invoke(HttpContext context)
{
//replace and revert original request stream
var requestBodyStream = new MemoryStream();
var originalRequestBody = context.Request.Body;
await context.Request.Body.CopyToAsync(requestBodyStream);
requestBodyStream.Seek(0, SeekOrigin.Begin);
var bodyContentService = context.RequestServices.GetService(typeof(BodyContentService))
as BodyContentService;
bodyContentService.Body = requestBodyStream.ToArray();
requestBodyStream.Seek(0, SeekOrigin.Begin);
context.Request.Body = requestBodyStream;
await _next(context);
context.Request.Body = originalRequestBody; //restore request body
}
}
PS: You need to register it in startup:
app.UseMiddleware<RequestReaderMiddleWare>();