[c#] Read HttpContent in WebApi controller

How can I read the contents on the PUT request in MVC webApi controller action.

[HttpPut]
public HttpResponseMessage Put(int accountId, Contact contact)
{
    var httpContent = Request.Content;
    var asyncContent = httpContent.ReadAsStringAsync().Result;
...

I get empty string here :(

What I need to do is: figure out "what properties" were modified/sent in the initial request (meaning that if the Contact object has 10 properties, and I want to update only 2 of them, I send and object with only two properties, something like this:

{

    "FirstName": null,
    "LastName": null,
    "id": 21
}

The expected end result is

List<string> modified_properties = {"FirstName", "LastName"}

This question is related to c# asp.net-mvc asp.net-web-api httpcontent

The answer is


You can keep your CONTACT parameter with the following approach:

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());
}

Returned for me the json representation of my parameter object, so I could use it for exception handling and logging.

Found as accepted answer here


Even though this solution might seem obvious, I just wanted to post it here so the next guy will google it faster.

If you still want to have the model as a parameter in the method, you can create a DelegatingHandler to buffer the content.

internal sealed class BufferizingHandler : DelegatingHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        await request.Content.LoadIntoBufferAsync();
        var result = await base.SendAsync(request, cancellationToken);
        return result;
    }
}

And add it to the global message handlers:

configuration.MessageHandlers.Add(new BufferizingHandler());

This solution is based on the answer by Darrel Miller.

This way all the requests will be buffered.


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