我正在尝试从HttpRequest消息中检索输入请求。 HttpRequest中的内容显示了内容类型和长度。 如何获取json？

Question

Current code

if (!(context.Exception is exception))
    HttpContent requestContent = context.Request.Content;
    string jsonContent = requestContent.ReadAsStringAsync().Result;

Jsoncontent returns null here as well as

context.request = context.HttpRequestMessage

Seeing below output in local window

context.Request.Content.Headers {
    Content-Length: 1458
    Content-Type: application/json
    }
Allow: {}
ContentDisposition: null
ContentEncoding: {}
ContentLanguage: {}
ContentLength: 1458
ContentLocation: null
ContentMD5: null
ContentRange: null
ContentType: { application/json }
Expires: null
LastModified: null
Results View: Expanding the Results View will enumerate the IEnumerable
context.Request.Content { System.Net.Http.StreamContent }
Headers: {
    Content-Length: 1458
    Content-Type: application/json
}

How do I retrieve content from header?

Answer 1

If you want content-type and length as json string, you can use

 JsonConvert.SerializeObject(Request.Content.Headers);

 // Sample output 
 // "[{\"Key\":\"Content-Length\",\"Value\":[\"29\"]},{\"Key\":\"Content-Type\",\"Value\":[\"application/json\"]}]"

requestContent.ReadAsStringAsync() return empty string because body can only be read once. If you want to read body using ReadAsStringAsync then remove parameter from actions (this will prevent default model binding).

   // This will have Request.Content.ReadAsStringAsync as ""
   public async Task<IHttpActionResult>  Post(MyModel model)

Change it to

   // This will have Request.Content.ReadAsStringAsync as json string
   public async Task<IHttpActionResult>  Post()

Blog explains this in more detail https://blogs.msdn.microsoft.com/jmstall/2012/04/16/how-webapi-does-parameter-binding/

Hope this help

Update

If you need request details in exception filter then you can use following options

Options 1 (easier and I would advise to use this)

Use

       context.ActionContext.ActionArguments

Example

        var requestJson = $"RequestUrl: {context.Request.RequestUri} " +
                          $"ActionName: {context.ActionContext.ActionDescriptor.ActionName} " +
                          $"Arguments: {JsonConvert.SerializeObject(context.ActionContext.ActionArguments)}";

        Debug.WriteLine(requestJson);

Options 2 copy RequestStream to MemoryStream and reread from position 0 (copied from link )

        string request;
        using (var memoryStream = new MemoryStream())
        {
            var requestStream = await context.Request.Content.ReadAsStreamAsync();
            requestStream.Position = 0;
            requestStream.CopyTo(memoryStream);
            memoryStream.Position = 0;
            using (StreamReader streamReader = new StreamReader(memoryStream))
            {
                request = streamReader.ReadToEnd();
            }
        }

        Debug.WriteLine(request)