我正在尝试让我的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,并返回结果JSON,而不是返回响应对象本身.
这是我的控制器方法：
[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;
}
}
AzureFilesClient上的GetFileStream方法在此处,但流源可以是包含二进制文件内容的任何内容：
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;
}
}
编辑：以下是JSON响应的示例：
{
"Version": {
"Major": 1,"Minor": 1,"Build": -1,"Revision": -1,"MajorRevision": -1,"MinorRevision": -1
},"Content": {
"Headers": [
{
"Key": "Content-Type","Value": [
"application/octet-stream"
]
},{
"Key": "Content-Disposition","Value": [
"attachmentx; filename=\"samplefile.docx\""
]
}
]
},"StatusCode": 200,"ReasonPhrase": "OK","Headers": [],"RequestMessage": null,"IsSuccessStatusCode": true
}
解决方法
在结合阅读文档以及一些反复试验之后,问题就解决了.
Azure部分是使用nuGet包“WindowsAzure.Storage”(4.4.1预览版)制作的
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.
