ASP.NET MVC4 WebAPI and Posting XML data

The following will allow you to read a raw XML message via a POST to a Web API method:

public void PostRawXMLMessage(HttpRequestMessage request){   var xmlDoc = new XmlDocument();   xmlDoc.Load(request.Content.ReadAsStreamAsync().Result);   }

You can debug and inspect the body, headers, etc. and will see the raw XML posted. I used Fiddler's Composer to make a HTTP POST and this works well.

You are sending content type of text/xml but you have defined your parameter as string. Ideally your XML should be mapped to a class so that it can be deserialised.

So if you need raw xml then it is not supported yet. Web API currently is geared up for serialization MediaTypeFormatters and missing simple type formatters but they can easily built.

This one is a minimal implementation of such formatter supporting only read in your case and based on beta installer (and not nightly source code since it has substantially changed):

public class TextMediaTypeFormatter : MediaTypeFormatter{    public TextMediaTypeFormatter()    {        SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/xml"));        SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/plain"));        SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/javascript"));    }    protected override bool CanReadType(Type type)    {        return type == typeof (string);    }    protected override System.Threading.Tasks.Task<object> OnReadFromStreamAsync(Type type, Stream stream,         HttpContentHeaders contentHeaders,         FormatterContext formatterContext)    {        var taskCompletionSource = new TaskCompletionSource<object>();        try        {            var memoryStream = new MemoryStream();            stream.CopyTo(memoryStream);            var s = System.Text.Encoding.UTF8.GetString(memoryStream.ToArray());            taskCompletionSource.SetResult(s);        }        catch (Exception e)        {            taskCompletionSource.SetException(e);                   }        return taskCompletionSource.Task;    }}

And to use it, just add it to formatters collection:

GlobalConfiguration.Configuration.Formatters.Insert(0, new TextMediaTypeFormatter());

Anyone looking for an updated version of Aliostad's answer above from the beta release to the RC of asp.net mvc 4 web api (minor changes resulted in a slight rework for me).

public class TextMediaTypeFormatter : MediaTypeFormatter{    public TextMediaTypeFormatter()    {        SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/xml"));        SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/plain"));        SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/javascript"));    }    public override bool CanReadType(Type type)    {        if (type == typeof(String))            return true;        else            return false;    }    public override bool CanWriteType(Type type)    {        if (type == typeof(String))            return true;        else            return false;    }    public override Task<object> ReadFromStreamAsync(Type type, Stream readStream, System.Net.Http.HttpContent content, IFormatterLogger formatterLogger)    {        var taskCompletionSource = new TaskCompletionSource<object>();        try        {            var memoryStream = new MemoryStream();            readStream.CopyTo(memoryStream);            var s = System.Text.Encoding.UTF8.GetString(memoryStream.ToArray());            taskCompletionSource.SetResult(s);        }        catch (Exception e)        {            taskCompletionSource.SetException(e);        }        return taskCompletionSource.Task;    }}