逻辑说明
webapi返回类型为IHttpActionResult接口，内部方法返回HttpResponseMessage。
public interface IHttpActionResult
{
Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken);
}
参照JsonResult<T>，自定义返回文件流。
主要为：设置文件响应内容流，文件内容类型，文件名。
HttpResponseMessage httpResponseMessage = new HttpResponseMessage(HttpStatusCode.OK);
httpResponseMessage.Content = new StreamContent(_stream);
httpResponseMessage.Content.Headers.ContentType = new MediaTypeHeaderValue(_mediaType);
httpResponseMessage.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
{
FileName = HttpUtility.UrlEncode(_fileName, Encoding.UTF8),
};
完整代码
完整FileStreamResult如下：
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<HttpResponseMessage>(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;
}
}
}
使用方法：
[HttpGet]
public IHttpActionResult Logo()
{
var path = HostingEnvironment.MapPath("/files/logo.png");
var f = new FileInfo(path);
if (!f.Exists)
{
return new StatusCodeResult(HttpStatusCode.NotFound, this);
}
return new FileStreamResult(f.OpenRead(), "image/png");
} [HttpGet]
public IHttpActionResult D()
{
var path = HostingEnvironment.MapPath("/files/d.docx");
var f = new FileInfo(path);
if (!f.Exists)
{
return new StatusCodeResult(HttpStatusCode.NotFound, this);
}
return new FileStreamResult(f.OpenRead(), "application/octet-stream", "中文的jun2019.docx");
}
扩展的FileByteResult
public class FileByteResult : FileStreamResult
{
public FileByteResult(byte[] buffer, string mediaType) : base(new MemoryStream(buffer), mediaType) { } public FileByteResult(byte[] buffer, string mediaType, string fileName) : base(new MemoryStream(buffer), mediaType, fileName) { }
}