How to download a file in ASP.NET Core

Question

In MVC, we have used following code to download a file. In ASP.NET core, how to achieve this?

HttpResponse response = HttpContext.Current.Response;                   


        

Answer 1

Here is my Medium article, describing everything step by step (it also includes a GitHub repo): https://medium.com/@tsafadi/download-a-file-with-asp-net-core-e23e8b198f74

Any ways this is how the controller should look like:

[HttpGet]
public IActionResult DownloadFile()
{
    // Since this is just and example, I am using a local file located inside wwwroot
    // Afterwards file is converted into a stream
    var path = Path.Combine(_hostingEnvironment.WebRootPath, "Sample.xlsx");
    var fs = new FileStream(path, FileMode.Open);

    // Return the file. A byte array can also be used instead of a stream
    return File(fs, "application/octet-stream", "Sample.xlsx");
}

Inside the view:

$("button").click(function () {
    var xhr = new XMLHttpRequest();
    xhr.open("GET", "Download/DownloadFile", true);
    xhr.responseType = "blob";
    xhr.onload = function (e) {
        if (this.status == 200) {
            var blob = this.response;

            /* Get filename from Content-Disposition header */
            var filename = "";
            var disposition = xhr.getResponseHeader('Content-Disposition');
            if (disposition && disposition.indexOf('attachment') !== -1) {
                var filenameRegex = /filename[^;=\n]*=((['"]).*?\2|[^;\n]*)/;
                var matches = filenameRegex.exec(disposition);
                if (matches != null && matches[1]) filename = matches[1].replace(/['"]/g, '');
            }

            // This does the trick
            var a = document.createElement('a');
            a.href = window.URL.createObjectURL(blob);
            a.download = filename;
            a.dispatchEvent(new MouseEvent('click'));
        }
    }
    xhr.send();
});