Web Api通过文件流下载文件到本地实例

最近项目里面需要和C++的客户端互动，其中一个接口就是需要提供文件下载的接口，保证C++项目调用这个接口的时候能够正常下载文件到本地。参考了一下网上的代码，其原理就是读取服务器上指定路径的文件流，并将文件流包装成返回的HttpResponseMessage的StreamContent。具体实现代码如下：

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;
using System.Web;
using System.Web.Http;

namespace WebAPI.Controllers
{
    public class DownloadFileController : ApiController
    {
        /// <summary>
        /// 从WebAPI下载文件
        /// </summary>
        /// <returns></returns>
        public IHttpActionResult GetFileFromWebApi()
        {
            var browser = String.Empty;
            if (HttpContext.Current.Request.UserAgent != null)
            {
                browser = HttpContext.Current.Request.UserAgent.ToUpper();
            }
            string filePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Content", "标准事件.png");
            HttpResponseMessage httpResponseMessage = new HttpResponseMessage(HttpStatusCode.OK);
            FileStream fileStream = File.OpenRead(filePath);
            httpResponseMessage.Content = new StreamContent(fileStream);
            httpResponseMessage.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
            httpResponseMessage.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
            {
                FileName =
                    browser.Contains("FIREFOX")
                        ? Path.GetFileName(filePath)
                        : HttpUtility.UrlEncode(Path.GetFileName(filePath))
                //FileName = HttpUtility.UrlEncode(Path.GetFileName(filePath))
            };

            return ResponseMessage(httpResponseMessage);
        }
    }
}