在ASP.NET MVC中将文件从控制器发送到远程ApiController的通用有效方法

Question

I am working on a multi-level ASP.NET MVC web platform and I have the requirement to send a file from a System.Web.Mvc.Controller to an ASP.NET MVC web-service's System.Web.Http.ApiController , running remotely on a different machine.

Currently, I have this in my Mvc.Controller :

public ActionResult ForwardThisFile(HttpPostedFileBase file)
{
    // TODO: Forward file to remote DocumentApi:
    DocumentApi.DocumentApiClient client = new DocumentApi.DocumentApiClient();
    client.StoreDocument(file /* <-- How-To? */);
    return View();
}

where the DocumentApiClient has been generated via Visual Studio's Add REST API Client... function from a Swagger Url. (The generated client internally uses the Microsoft.Rest.ClientRuntime which is relying on System.Net.Http.HttpClient , HttpRequestMessage , etc.)

The question is, how do I define and implement the DocumentApi to transfer files to it in an efficient and generic way in the ApiController . Currently, I am thinking of three different options:

• [HttpPut] public async Task<IHttpActionResult> StoreDocument(HttpPostedFileBase file)
• [HttpPut] public async Task<IHttpActionResult> StoreDocument(byte[] fileContents, string contentType, string fileName)
• [HttpPut] public async Task<IHttpActionResult> StoreDocument(Stream fileStream, string contentType, string fileName)

I was thinking, that maybe I could just forward the HttpPostedFileBase instance from the Mvc.Controller to the ApiController , so I've tried the first option. However, Add REST API Client... creates a DocumentApi.Models.HttpPostedFileBase model class in that case and is NOT of the original type System.Web.HttpPostedFileBase . Now, I'm not sure what I should do...

new DocumentApi.Models.HttpPostedFileBase() {
    InputStream = file.InputStream,
    ContentType = file.ContentType,
    ContentLength = file.ContentLength,
    FileName = file.FileName,
}

^ that doesn't work, because for the InputStream , it creates a DocumentApi.Models.Stream class and I have no idea how to convert the System.IO.Stream from the file parameter into a DocumentApi.Models.Stream .

Is it even possible to send a stream across ASP.NET MVC webservices? (Which would basically be the answer to option 3)

In my current state of knowledge, the only alternative appears to me being option 2, where I would send a byte-array containing the whole file. I am asking myself, however, if there is any more convenient or more efficient way to send a file from a Mvc.Controller to a remote ApiController . Is there?
Which one of the options would work and which one is the way to go?

Additionally, I have a bonus question to the above regarding HttpPostedFileBase : Is the way via HttpPostedFileBase the most efficient way to handle uploaded files in ASP.NET MVC? I have seen various alternatives:

• HttpPostedFileBase like shown above in the first code sample
• Using the raw HTTP-request via Request.Content.ReadAsStreamAsync() or something similar. Maybe the stream is more efficient for my use case?
• Using JavaScript to encode a file into a Base64 string and send it via a hidden input field to the controller. (via FileReader 's method readAsDataURL(file) )

So many options... Which one is best/most generic/most efficient?

Answer 1

You should use the HttpClient lib in the calling controller to async upload the file to the destination controller. Various examples of using HttpClient to asycn upload is here C# HttpClient 4.5 multipart/form-data upload .

In this case your receiving remote controller just acts as though its having a file uploaded from a browser with no specific handling required.