Reading response body stream resulted in an empty string

Question

I'm using .netCore 3.1 to create a RESTful API.

Here I'm trying to modify the response body to filter out some values based on a corporate use case that I have.

My problem is that at first, I figured that the CanRead value of context.HttpContext.Response.Body is false, thus it is unreadable, so I searched around and found this question and its answers .

which

basically converts a stream that can't seek to one that can

so I applied the answer with a little modification to fit my use case:

        Stream originalBody = context.HttpContext.Response.Body;

        try
        {
            using (var memStream = new MemoryStream())
            {
                context.HttpContext.Response.Body = memStream;


                memStream.Position = 0;
                string responseBody = new StreamReader(memStream).ReadToEnd();

                memStream.Position = 0;
                memStream.CopyTo(originalBody);
                string response_body = new StreamReader(originalBody).ReadToEnd();
                PagedResponse<List<UserPhoneNumber>> deserialized_body;
                deserialized_body = JsonConvert.DeserializeObject<PagedResponse<List<UserPhoneNumber>>>(response_body);
                // rest of code logic
            }

        }
        finally
        {
            context.HttpContext.Response.Body = originalBody;
        }

But when debugging, I found out that memStream.Length is always 0 , and therefore the originalBody value is an empty string: "" . Even though after this is executed, the response is returned successfully, (thanks to the finally block).

I can't seem to understand why this is happening, is this an outdated method? what am I doing wrong? Thank you in advance.

Answer 1

using is closing the stream try

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