How to generate Body Parameters/ Sample Request for Web API Help Page while having access to raw request body

Question

I need help populating the Body Parameters for the documentation of this endpoint. It shows as empty:

I realize that the reason this is happening is because I am currently reading the request body and then converting the information to PackageUpdate. Since I am reading the raw request body this way, the task has no parameters which will cause the help page to not specify any.

Sample Request:

{
  "PackageId": "package/3e585e1c-d6cd-4b6c-aa1c-aa674d11c944",
  "SoldDateTime": "2018-08-13 19:57:54.000",
  "GuaranteeTermExpiresDate": null
}

PackageUpdate class:

    [DataContract]
    public class PackageUpdate: BaseRequest
    {
        /// <summary>
        ///     Get or Set the package ID of the package to update
        /// </summary>
        [Required]
        [DataMember]
        public string PackageId { get; set; }

        /// <summary>
        ///     Get or Set the Sold Date Time field of the package
        /// </summary>
        [DataMember]
        public DateTime? SoldDateTime { get; set; }

        /// <summary>
        ///     Get or Set the Guarantee Term Expires Date field of the package
        /// </summary>
        [DataMember]
        public DateTime? GuaranteeTermExpiresDate { get; set; }

        /// <summary>
        ///     Get or Set the Premium Promised On field of the package
        /// </summary>
        [DataMember]
        public DateTime? PremiumPromisedOn { get; set; }
    }

UpdatePackageAsync Method:

        /// <summary>
        ///     Updates a package.
        /// </summary>
        [Route("update"), Description("Patch a specific package")]
        [HttpPatch]
        [ResponseType(typeof(Package))]
        public async Task<IHttpActionResult> UpdatePackageAsync()
        {
            string requestBody = await Request.Content.ReadAsStringAsync();
            PackageUpdate request = new PackageUpdate();

            try
            {
                JsonSerializerSettings settings = new JsonSerializerSettings{ MissingMemberHandling = MissingMemberHandling.Error };
                request = JsonConvert.DeserializeObject<PackageUpdate>(requestBody, settings);
            }   
            catch(Exception e)
            {
                return BadRequest("Patch Error -> " + e.Message);
            }

            //Do stuff with request

        }

How can I possibly get the Body Parameters field on the documentation to reflect the properties of PackageUpdate, and still have access to the raw request body?

I previously tried the below solution from a different post but it wouldn't allow me access to the request body as a string.

public async Task<IHttpActionResult> UpdatePackageAsync([FromBody] PackageUpdate request)

Answer 1

I ended up trying multiple solutions that I found on the site and then found a solution (here) that allows me to seek to the beginning of the stream, copy to a new stream, and return the body to my Task.

Solution:

using (var stream = new MemoryStream())
{
    var context = (HttpContextBase)Request.Properties["MS_HttpContext"];
    context.Request.InputStream.Seek(0, SeekOrigin.Begin);
    context.Request.InputStream.CopyTo(stream);
    string requestBody = Encoding.UTF8.GetString(stream.ToArray());
}

Applicable to my code, I used it in this way:

public async Task<IHttpActionResult> UpdatePackageAsync(PackageUpdate request)
{
     string requestBody = ReadInputStream();
     // do stuff with request
}

private string ReadInputStream()
{
      using (var stream = new MemoryStream())
      {
           var context = (HttpContextBase)Request.Properties["MS_HttpContext"];
           context.Request.InputStream.Seek(0, SeekOrigin.Begin);
           context.Request.InputStream.CopyTo(stream);
           return Encoding.UTF8.GetString(stream.ToArray());
      }
}