Question

我试图让我的ASP.Net 5 MVC 6 WebAPI项目输出一个文件，以响应HttpGET请求。

该文件来自Azure Files共享，但它可以是包含二进制文件的任何流。

在我看来，MVC序列化响应对象，并返回生成的JSON，而不是返回响应对象本身。

这是我的控制器方法：

var data = $('#example').dataTable().fnGetData();

AzureFilesClient上的GetFileStream方法在这里，尽管流源可以是包含二进制文件内容的任何内容：

    [HttpGet]
    [Route("GetFile")]
    public HttpResponseMessage GetFile(string Username, string Password, string FullName)
    {

        var client = new AzureFilesClient.AzureFilesClient(Username, Password);
        Stream azureFileStream =  client.GetFileStream(FullName).Result;
        var fileName = Path.GetFileName(FullName);

        using (HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK))
        {
            response.Content = new StreamContent(azureFileStream);
            response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
            response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment") { FileName = fileName };
            return response;
        }
    }

编辑：以下是JSON响应的示例：

    public async Task<Stream> GetFileStream(string fileName)
    {
        var uri = new Uri(share.Uri + "/" + fileName);
        var file = new CloudFile(uri, credentials);

        using (var stream = new MemoryStream())
        {
            await file.DownloadToStreamAsync(stream);
            stream.Seek(0, SeekOrigin.Begin);
            return stream;
        }
    }

Answer 1

在阅读文档和一些试错之后，问题已经解决了。

Azure部分是使用nuGet包“WindowsAzure.Storage”（4.4.1-preview）制作的

首先获得JSON序列化的输出。这需要返回自定义操作结果。

using Microsoft.AspNet.Mvc;
using System.IO;
using System.Threading.Tasks;

public class FileResultFromStream : ActionResult
{
    public FileResultFromStream(string fileDownloadName, Stream fileStream, string contentType)
    {
        FileDownloadName = fileDownloadName;
        FileStream = fileStream;
        ContentType = contentType;
    }

    public string ContentType { get; private set; }
    public string FileDownloadName { get; private set; }
    public Stream FileStream { get; private set; }

    public async override Task ExecuteResultAsync(ActionContext context)
    {
        var response = context.HttpContext.Response;
        response.ContentType = ContentType;
        context.HttpContext.Response.Headers.Add("Content-Disposition", new[] { "attachment; filename=" + FileDownloadName });
        await FileStream.CopyToAsync(context.HttpContext.Response.Body);
    }
}

现在获取从Azure文件共享（或任何其他异步流源）流式传输的二进制数据

using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Auth;
using Microsoft.WindowsAzure.Storage.File;
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Threading.Tasks;

    public async Task<Stream> GetFileStreamAsync(string fileName)
    {
        var uri = new Uri(share.Uri + "/" + fileName);
        var file = new CloudFile(uri, credentials);

        // Note: Do not wrap the stream variable in a Using, since it will close the stream too soon.
        var stream = new MemoryStream();
        await file.DownloadToStreamAsync(stream);
        stream.Seek(0, SeekOrigin.Begin);
        return stream;
    }

最后是控制器代码。注意使用IActionResult接口。

    [HttpGet]
    [Route("GetFile")]
    public async Task<IActionResult> GetFile(string username, string password, string fullName)
    {
        var client = new AzureFilesClient.AzureFilesClient(username, password);
        Stream stream = await client.GetFileStreamAsync(fullName);
        string fileName = Path.GetFileName(fullName);
        return new CustomActionResults.FileResultFromStream(fileName, stream, "application/msword");
    }

注意：此示例仅用于Word文件，您可能希望将ContentType参数设置为动态，而不是像这样静态。

MVC 6 WebAPI返回序列化的HttpResponseMessage而不是文件流

1 个答案: