List files inside ZIP file located on SFTP server in C#

问题

I need to process folders inside a ZIP file from SFTP server (WinSCP) programmatically through ASP.NET Core.

Is there any way where I can get list of files inside ZIP file without downloading to local computer? As the file size would be high and won't be in a consistent manner. Any help would be appreciated.

回答1:

With SSH.NET library, it could be as easy as:

using (var client = new SftpClient(host, username, password)
{
    client.Connect();

    using (Stream stream = client.OpenRead("/remote/path/archive.zip"))
    using (var archive = new ZipArchive(stream, ZipArchiveMode.Read))
    {
        foreach (var entry in archive.Entries)
        {
            Console.WriteLine(entry);
        }
    }
}

You need to reference System.IO.Compression assembly to get the ZipArchive.

The code will only read (download) the ZIP central directory record, not whole ZIP archive.

Unfortunately, there's a bug in the library. To workaround it, you have to implement a wrapper Stream implementation like this:

class FixStream : Stream
{
    public override long Seek(long offset, SeekOrigin origin)
    {
        long result;
        // workaround for SSH.NET bug in implementation of SeekOrigin.End
        if (origin == SeekOrigin.End)
        {
            result = _stream.Seek(Length + offset, SeekOrigin.Begin);
        }
        else
        {
            result = _stream.Seek(offset, origin);
        }
        return result;
    }

    // passthrough implementation of the rest of Stream interface

    public override bool CanRead => _stream.CanRead;

    public override bool CanSeek => _stream.CanSeek;

    public override bool CanWrite => _stream.CanWrite;

    public override long Length => _stream.Length;

    public override long Position { 
        get => _stream.Position; set => _stream.Position = value; }

    public FixStream(Stream stream)
    {
        _stream = stream;
    }

    public override void Flush()
    {
        _stream.Flush();
    }

    public override int Read(byte[] buffer, int offset, int count)
    {
        return _stream.Read(buffer, offset, count);
    }

    public override void SetLength(long value)
    {
        _stream.SetLength(value);
    }

    public override void Write(byte[] buffer, int offset, int count)
    {
        _stream.Write(buffer, offset, count);
    }

    private Stream _stream;
}

And wrap the SftpFileStream to it:

using (Stream stream = client.OpenRead("/remote/path/archive.zip"))
using (var stream2 = new FixStream(stream))
using (var archive = new ZipArchive(stream2, ZipArchiveMode.Read))
{
    ...
}

来源：https://stackoverflow.com/questions/63991495/list-files-inside-zip-file-located-on-sftp-server-in-c-sharp

标签

.net

asp.net-core

sftp

winscp