使用 FileContentResult 下载文件并使用 javascript 将其存储在客户端

Question

I've an MVC route as this:

public FileContentResult GetMedia(string media_md5)
{
    // get media from DB here 
    processed_file_doc file_doc = getMediaFromDb(media_md5);

    string filename = file_doc.Filename;
    string filepath = file_doc.File_path;

    byte[] fileBytes = System.IO.File.ReadAllBytes(filepath);
    string fileName = filename;

    FileContentResult file_result = File(fileBytes, System.Net.Mime.MediaTypeNames.Application.Octet, fileName);

    return file_result;
}

This method is called by javascript in this way:

function DownloadMedia(row_id) {

    filetable = $('#mytable').DataTable();
    var data = filetable.row('#' + row_id).data();
    filename = data['Filename'];

    var handleSuccess = function (file) {
        var a = document.createElement("a"),
            file = new Blob([file], { type: "application/octect-stream" });
        
            var url = URL.createObjectURL(file);
            a.href = url;
            a.download = filename;
            document.body.appendChild(a); 
            a.click();
            setTimeout(function () {
                document.body.removeChild(a);
                window.URL.revokeObjectURL(url);
            }, 0);     
    }

    $.post("/MyController/GetMedia", { media_md5: row_id }, handleSuccess);
}

The problem is that using this code I can correctly download only.txt files, if for example I try to download a.jpg, the image can't be opened. I've checked the two file downloaded and they are really different:

I've verified that the file is open and read correctly, but I can't understand why once received from client it is all messed up.

Answer 1

System.Net.Mime.MediaTypeNames.Application.Octet

为每个文件选择正确的 MimeType

Answer 2

Try checking

1. The url for the file is correct with right extension

2. Errors logged in the browser console. (F12 to open developer tools > Console)

Answer 3

Use octet-stream instead of octect-stream