ASP.NET Core Return Files, User Download Files, Download Files from Website, Dynamic File Download

2019年12月15日 88点热度 1人点赞 0条评论

内容目录

In ASP.NET Core, files can be added to a static directory for direct download. However, this method may not be secure or flexible enough.

We can add an action in the Controller to access any file on the server through this action.

Action Format

public FileResult Down()
        {
                    return File(xxx,xxx,xxx);
        }

Returns FileResult type, File() object

It's that simple.

File() Object

The question is how to write this File() object

Here's an example from the author

Under 100% error-free conditions, the file path is F:\a.txt

1. Create a FileStream

2. Get the file type Content-Type, which can either be obtained programmatically or filled in as a string

3. Set the file name

var stream = System.IO.File.OpenRead(“F:\a.txt”);  // Create file stream

The file type for .txt is text/plain

Set the file name to b.txt

Then the returned File code is as follows

return File(stream, "text/plain", “b.txt");

It's that simple.

Getting the File Type

You can refer to C# for getting the file type

http://www.cnblogs.com/zzsdream/articles/5796763.html

About the corresponding Context-Type of file types

http://tool.oschina.net/commons/

The author attaches a small method

//Import
using System.IO;
var contentype = MimeMapping.GetMimeMapping(fileName);  　　　　// Get file type

Dynamic File Retrieval

public FileResult DownSH(string DownM)  // The file code to download
        {
            var path = _sqlContext.jexusSqls.FirstOrDefault(a => a.DownM == DownM.ToString()).FilePath;  // Find the file address in the database
            if (!System.IO.File.Exists(path)) return null;
        </span><span style="color: #0000ff;">var</span> stream = <span style="color: #000000;">System.IO.File.OpenRead(path);  // Create file stream

        </span><span style="color: #0000ff;">return</span> File(stream, <span style="color: #800000;">"</span><span style="color: #800000;">application/x-sh</span><span style="color: #800000;">"</span>, DownM+<span style="color: #800000;">"</span><span style="color: #800000;">.sh</span><span style="color: #800000;">"</span><span style="color: #000000;">);
    }</span></pre>

There are many ways to write, you just need to address the three core elements of file stream, file type, and file name.

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