Files
Umbraco-CMS/src/Umbraco.Web/WebApi/HttpActionContextExtensions.cs

102 lines
4.5 KiB
C#

using System;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using System.Web.Http;
using System.Web.Http.Controllers;
using Newtonsoft.Json;
using Umbraco.Core.IO;
namespace Umbraco.Web.WebApi
{
internal static class HttpActionContextExtensions
{
/// <summary>
/// Helper method to get a model from a multipart request and ensure that the model is validated
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="actionContext"></param>
/// <param name="result"></param>
/// <param name="requestKey"></param>
/// <param name="validationKeyPrefix"></param>
/// <returns></returns>
public static T GetModelFromMultipartRequest<T>(this HttpActionContext actionContext, MultipartFormDataStreamProvider result, string requestKey, string validationKeyPrefix = "")
{
if (result.FormData[requestKey/*"contentItem"*/] == null)
{
var response = actionContext.Request.CreateResponse(HttpStatusCode.BadRequest);
response.ReasonPhrase = $"The request was not formatted correctly and is missing the '{requestKey}' parameter";
throw new HttpResponseException(response);
}
//get the string json from the request
var contentItem = result.FormData[requestKey];
//deserialize into our model
var model = JsonConvert.DeserializeObject<T>(contentItem);
//get the default body validator and validate the object
var bodyValidator = actionContext.ControllerContext.Configuration.Services.GetBodyModelValidator();
var metadataProvider = actionContext.ControllerContext.Configuration.Services.GetModelMetadataProvider();
//by default all validation errors will not contain a prefix (empty string) unless specified
bodyValidator.Validate(model, typeof(T), metadataProvider, actionContext, validationKeyPrefix);
return model;
}
/// <summary>
/// Helper method to get the <see cref="MultipartFormDataStreamProvider"/> from the request in a non-async manner
/// </summary>
/// <param name="actionContext"></param>
/// <param name="rootVirtualPath"></param>
/// <returns></returns>
public static MultipartFormDataStreamProvider ReadAsMultipart(this HttpActionContext actionContext, string rootVirtualPath)
{
if (actionContext.Request.Content.IsMimeMultipartContent() == false)
{
throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
}
var root = IOHelper.MapPath(rootVirtualPath);
//ensure it exists
Directory.CreateDirectory(root);
var provider = new MultipartFormDataStreamProvider(root);
var request = actionContext.Request;
var content = request.Content;
// Note: YES this is super strange, ugly, and weird.
// One would think that you could just do:
//
//var result = content.ReadAsMultipartAsync(provider).Result;
//
// But it deadlocks. See https://stackoverflow.com/questions/15201255 for details, which
// points to https://msdn.microsoft.com/en-us/magazine/jj991977.aspx which contains more
// details under "Async All the Way" - see also https://olitee.com/2015/01/c-async-await-common-deadlock-scenario/
// which contains a simplified explanation: ReadAsMultipartAsync is meant to be awaited,
// not used in the non-async .Result way, and there is nothing we can do about it.
//
// Alas, model binders cannot be async "all the way", so we have to wrap in a task, to
// force proper threading, and then it works.
MultipartFormDataStreamProvider result = null;
var task = Task.Run(() => content.ReadAsMultipartAsync(provider))
.ContinueWith(x =>
{
if (x.IsFaulted && x.Exception != null)
{
throw x.Exception;
}
result = x.ConfigureAwait(false).GetAwaiter().GetResult();
});
task.Wait();
if (result == null)
throw new InvalidOperationException("Could not read multi-part message");
return result;
}
}
}