Return jpeg image from Asp.Net Core WebAPI

hannes neukermans picture hannes neukermans · Nov 24, 2016 · Viewed 45.6k times · Source

Using asp.net core web api, I want to have my controller action method to return an jpeg image stream.
In my current implementation, browser displays only a json string. My expectation is to see the image in the browser.

While debugging using chrome developer tools I found that the content type is still

Content-Type:application/json; charset=utf-8

returned in the response header, even though in my code I manually set the content type to "image/jpeg".

Looking for a solution My Web API is as below

[HttpGet]
public async Task<HttpResponseMessage> Get()
{
    var image = System.IO.File.OpenRead("C:\\test\random_image.jpeg");
    var stream = new MemoryStream();

    image.CopyTo(stream);
    stream.Position = 0;            
    result.Content = new StreamContent(image);
    result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
    result.Content.Headers.ContentDisposition.FileName = "random_image.jpeg";
    result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg");
    result.Content.Headers.ContentLength = stream.Length;

    return result;
}

enter image description here

Answer

hannes neukermans picture hannes neukermans · Nov 24, 2016

Clean solution use FilestreamResult !!

[HttpGet]
public async Task<IActionResult> Get()
{
    var image = System.IO.File.OpenRead("C:\\test\\random_image.jpeg");
    return File(image, "image/jpeg");
}

Explanation:

In ASP.NET Core you have to use the built-in File() method inside the Controller. This will allow you to manually set the content type.

Don't create and return HttpResponseMessage, like you were used to using in ASP.NET Web API 2. It doesn't do anything, not even throwing errors!!