[ACCEPTED]-How to pass XML as POST to an ActionResult in ASP MVC .NET-actionresult

@Freddy - liked your approach and improved 3 on it with the following code to simplify 2 stream reading:

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        HttpContextBase httpContext = filterContext.HttpContext;
        if (!httpContext.IsPostNotification)
        {
            throw new InvalidOperationException("Only POST messages allowed on this resource");
        }

        Stream httpBodyStream = httpContext.Request.InputStream;
        if (httpBodyStream.Length > int.MaxValue)
        {
            throw new ArgumentException("HTTP InputStream too large.");
        }

        StreamReader reader = new StreamReader(httpBodyStream, Encoding.UTF8);
        string xmlBody = reader.ReadToEnd();
        reader.Close();

        filterContext.ActionParameters["message"] = xmlBody;

        // Sends XML Data To Model so it could be available on the ActionResult
        base.OnActionExecuting(filterContext);
    }

Then in the Controller you 1 can access the xml as a string:

[RestAPIAttribute]    
public ActionResult MyActionResult(string message)    
{         

}

This could be accomplished by using the 9 ActionFilterAttribute. Action Filters basically 8 intersects the request before or after the 7 Action Result. So I just built a custom 6 action filter attribute for POST Action 5 Result. Here is what I did:

public class RestAPIAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        HttpContextBase httpContext = filterContext.HttpContext;
        if (!httpContext.IsPostNotification)
        {
            throw new InvalidOperationException("Only POST messages allowed on this resource");
        }
        Stream httpBodyStream = httpContext.Request.InputStream;

        if (httpBodyStream.Length > int.MaxValue)
        {
            throw new ArgumentException("HTTP InputStream too large.");
        }

        int streamLength = Convert.ToInt32(httpBodyStream.Length);
        byte[] byteArray = new byte[streamLength];
        const int startAt = 0;

        /*
         * Copies the stream into a byte array
         */
        httpBodyStream.Read(byteArray, startAt, streamLength);

        /*
         * Convert the byte array into a string
         */
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < streamLength; i++)
        {
            sb.Append(Convert.ToChar(byteArray[i]));
        }

        string xmlBody = sb.ToString();

        //Sends XML Data To Model so it could be available on the ActionResult

        base.OnActionExecuting(filterContext);
    }
}

Then on the 4 action result method on your controller 3 you should do something like this:

    [RestAPIAttribute]
    public ActionResult MyActionResult()
    {
        //Gets XML Data From Model and do whatever you want to do with it
    }

Hope this 2 helps somebody else, if you think there 1 are more elegant ways to do it, let me know.

Why can they not pass the xml as a string 3 in the form post?

Example:

public ActionResult SendMeXml(string xml)
{
  //Parse into a XDocument or something else if you want, and return whatever you want.
  XDocument xmlDocument = XDocument.Parse(xml);

  return View();
}

You could create 2 a form post and send it in a single form 1 field.

I know you can create a custom value provider 7 factory. This will let you also validate 6 your models when they are posted before 5 attempting to save them. Phil Haack has a blog post 4 about a JSON version of this same concept. The 3 only problem is that I don't know how to 2 implement one this same sort of thing for 1 XML.

IMO the best way to accomplish this is to 6 write a custom value provider, this is 5 a factory that handles the mapping of the 4 request to the forms dictionary. You just 3 inherit from ValueProviderFactory and handle 2 the request if it is of type “text/xml” or 1 “application/xml.”

More Info:

Phil Haack

My blog

MSDN

protected override void OnApplicationStarted()
{
    AreaRegistration.RegisterAllAreas();

    RegisterRoutes(RouteTable.Routes);

    ValueProviderFactories.Factories.Add(new JsonValueProviderFactory());
    ValueProviderFactories.Factories.Add(new XmlValueProviderFactory());
}

XmlValueProviderFactory

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Web.Mvc;
using System.Xml;
using System.Xml.Linq;

public class XmlValueProviderFactory : ValueProviderFactory
{

    public override IValueProvider GetValueProvider(ControllerContext controllerContext)
    {
        var deserializedXml = GetDeserializedXml(controllerContext);

        if (deserializedXml == null) return null;

        var backingStore = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);

        AddToBackingStore(backingStore, string.Empty, deserializedXml.Root);

        return new DictionaryValueProvider<object>(backingStore, CultureInfo.CurrentCulture);

    }

    private static void AddToBackingStore(Dictionary<string, object> backingStore, string prefix, XElement xmlDoc)
    {
        // Check the keys to see if this is an array or an object
        var uniqueElements = new List<String>();
        var totalElments = 0;
        foreach (XElement element in xmlDoc.Elements())
        {
            if (!uniqueElements.Contains(element.Name.LocalName))
                uniqueElements.Add(element.Name.LocalName);
            totalElments++;
        }

        var isArray = (uniqueElements.Count == 1 && totalElments > 1);


        // Add the elements to the backing store
        var elementCount = 0;
        foreach (XElement element in xmlDoc.Elements())
        {
            if (element.HasElements)
            {
                if (isArray)
                    AddToBackingStore(backingStore, MakeArrayKey(prefix, elementCount), element);
                else
                    AddToBackingStore(backingStore, MakePropertyKey(prefix, element.Name.LocalName), element);
            }
            else
            {
                backingStore.Add(MakePropertyKey(prefix, element.Name.LocalName), element.Value);
            }
            elementCount++;
        }
    }


    private static string MakeArrayKey(string prefix, int index)
    {
        return prefix + "[" + index.ToString(CultureInfo.InvariantCulture) + "]";
    }

    private static string MakePropertyKey(string prefix, string propertyName)
    {
        if (!string.IsNullOrEmpty(prefix))
            return prefix + "." + propertyName;
        return propertyName;
    }

    private XDocument GetDeserializedXml(ControllerContext controllerContext)
    {
        var contentType = controllerContext.HttpContext.Request.ContentType;
        if (!contentType.StartsWith("text/xml", StringComparison.OrdinalIgnoreCase) &&
            !contentType.StartsWith("application/xml", StringComparison.OrdinalIgnoreCase))
            return null;

        XDocument xml;
        try
        {
            var xmlReader = new XmlTextReader(controllerContext.HttpContext.Request.InputStream);
            xml = XDocument.Load(xmlReader);
        }
        catch (Exception)
        {
            return null;
        }

        if (xml.FirstNode == null)//no xml.
            return null;

        return xml;
    }
}

I like the answer from @Freddy and improvement 11 from @Bowerm. It is concise and preserves 10 the format of form-based actions.

But the 9 IsPostNotification check will not work in 8 production code. It does not check the 7 HTTP verb as the error message seems to 6 imply, and it is stripped out of HTTP context 5 when compilation debug flag is set to false. This 4 is explained here: HttpContext.IsPostNotification is false when Compilation debug is false

I hope this saves someone 3 a 1/2 day of debugging routes due to this 2 problem. Here is the solution without that 1 check:

public class XmlApiAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        HttpContextBase httpContext = filterContext.HttpContext;
        // Note: for release code IsPostNotification stripped away, so don't check it!
        // https://stackoverflow.com/questions/28877619/httpcontext-ispostnotification-is-false-when-compilation-debug-is-false            

        Stream httpBodyStream = httpContext.Request.InputStream;
        if (httpBodyStream.Length > int.MaxValue)
        {
            throw new ArgumentException("HTTP InputStream too large.");
        }

        StreamReader reader = new StreamReader(httpBodyStream, Encoding.UTF8);
        string xmlBody = reader.ReadToEnd();
        reader.Close();

        filterContext.ActionParameters["xmlDoc"] = xmlBody;

        // Sends XML Data To Model so it could be available on the ActionResult
        base.OnActionExecuting(filterContext);
    }
}
...
public class MyXmlController 
{ ...
    [XmlApiAttribute]
    public JsonResult PostXml(string xmlDoc)
    {
...

Nice!,

What object I got in my controller 4 method to manipulate the Xml?

I'm using this 3 way:

On actionFilter, I populate the model 2 with:

        .
        .

        string xmlBody = sb.ToString();

        filterContext.Controller.ViewData.Model = xmlBody;

And on my controller method, I get 1 the Model as:

        string xmlUserResult = ViewData.Model as string;

        XmlSerializer ser = new XmlSerializer(typeof(UserDTO));
        StringReader stringReader = new StringReader(xmlUserResult);
        XmlTextReader xmlReader = new XmlTextReader(stringReader);
        UserDTO userToUpdate = ser.Deserialize(xmlReader) as UserDTO;
        xmlReader.Close();
        stringReader.Close();

Is this a correct implementation?

Thanks.