webApi返回文件流

定义返回结果

  
[DataContract]
public class FileStreamResult : IHttpActionResult
{
    readonly Stream _stream;
    readonly string _mediaType;
    readonly string _fileName;

    public FileStreamResult(Stream stream, string mediaType) : this(stream, mediaType, null) { }

    public FileStreamResult(Stream stream, string mediaType, string fileName)
    {
        _stream = stream;
        _mediaType = mediaType;
        _fileName = fileName;
    }

    public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        return Task.FromResult(Execute());
    }

    private HttpResponseMessage Execute()
    {
        HttpResponseMessage httpResponseMessage = new HttpResponseMessage(HttpStatusCode.OK);
        try
        {
            httpResponseMessage.Content = new StreamContent(_stream);
            httpResponseMessage.Content.Headers.ContentType = new MediaTypeHeaderValue(_mediaType);
            if (!string.IsNullOrEmpty(_fileName))
            {
                httpResponseMessage.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
                {
                    FileName = HttpUtility.UrlEncode(_fileName, Encoding.UTF8),
                };
            }
            return httpResponseMessage;
        }
        catch
        {
            httpResponseMessage.Dispose();
            throw;
        }
    }
}

使用

  
public async Task<FileStreamResult> GetFile(string path)
{
    var f = new FileInfo(path);
    //return new FileStreamResult(f.OpenRead(), "application/octet-stream", "result.docx");
    var mediaType = MimeMapping.GetMimeMapping(path);
    return new FileStreamResult(f.OpenRead(), mediaType, "result"+Path.GetExtension(path));
}

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