如何将任何文件下载到任何设备并查看？

Question

下面的代码是一个 API 调用，我在其中传递了一个 documentID 并尝试打开一个文档。由于整个过程都在服务器上运行，因此我无法在任何其他设备（无论是其他台式机还是移动设备）上查看该文件，尽管该文件将在服务器计算机中打开但不会在本地打开。谁能指导我了解我哪里出错了？ （对不起代码，我知道它可能并不完美，因为我是网络开发新手。还在学习）。

    {
        int i = 1;
        string key = ConfigurationManager.AppSettings["PhysicalDocumentPath"]; // some address like "xxx.xxx.xxx.xxx\folder\documents...."
        string key2 = ConfigurationManager.AppSettings["PhysicalDocumentPath2"]; // "C:\{somefolder}\{somefolder}...."
        JAppDoc value = new JAppDoc();
        var response = new Response();           
        try
        {
            if (!Directory.Exists(key2))
            {
                Directory.CreateDirectory(key2);
            }

            IAppDataService appDataService = new AppDataService();
            response = appDataService.GetDoc(docId, value);               

            var fileName = value.ApplicantId + "_" + value.DocumentName;
            var savefileName = fileName;
            var fileSavePath = Path.Combine(key, fileName);
            var prevPath = fileSavePath;
            var nextPath = fileSavePath;
            var tmp = fileName.Split('.');
            var tmp1 = tmp[0];                
            while (File.Exists(nextPath))
            {
                tmp = fileName.Split('.');                    
                fileName = tmp1 + i.ToString();
                fileName = fileName + "." + tmp[1];
                savefileName = fileName;                    
                nextPath = Path.Combine(key, savefileName);
                if (File.Exists(nextPath))
                {
                    prevPath = nextPath;
                }
                i++;
            }

            try
            {
                tmp = prevPath.Split(new[] { "Docs\\" }, StringSplitOptions.None);
                var serverpath = key + tmp[1];
                var localpath = key2+ tmp[1];
                if (File.Exists(localpath))
                {
                    Process.Start(localpath);
                }
                else
                {
                    System.IO.File.Copy(serverpath, localpath);
                    Process.Start(localpath);
                }
            }
           catch(Exception e)
            {
                Utils.Write(e);
                response.Message = "File not found !";                    
            }
        }
        catch (Exception ex)
        {
            Utils.Write(ex);
        }

        return Ok(response);
    }

Answer 1

为了从 Web API 下载文件，我使用继承自 IHttpActionResult 的自定义 FileResult 响应，如下所示：

/// <summary>
/// Http Action Result containing the requested document
/// </summary>
public class FileResult : IHttpActionResult
{
    private readonly string filePath;
    private readonly string contentType;
    private readonly byte[] content;
    private readonly string fileName;

    /// <summary>
    /// Initialise the action result with the path to the file and the content type. The contents of the file will be read.
    /// </summary>
    /// <param name="FilePath">Path to the file to read</param>
    /// <param name="ContentType">Type of content</param>
    public FileResult(string FilePath, string ContentType = null)
    {
        filePath = FilePath;
        fileName = Path.GetFileName(FilePath);
        contentType = ContentType;
    }

    /// <summary>
    /// Initialise the action result with the contents of the file, it's filename and the content type.
    /// </summary>
    /// <param name="Content"></param>
    /// <param name="FileName"></param>
    /// <param name="ContentType"></param>
    public FileResult(byte[] Content, string FileName, string ContentType)
    {
        content = Content;
        fileName = FileName;
        contentType = ContentType;
    }

    /// <summary>
    /// Creates an System.Net.Http.HttpResponseMessage asynchronously.
    /// </summary>
    /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
    /// <returns>A task that, when completed, contains the System.Net.Http.HttpResponseMessage.</returns>
    public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        return Task.Run(() =>
        {
            HttpContent output;
            if (filePath != null)
            {
                output = new StreamContent(File.OpenRead(filePath));
            }
            else
            {
                output = new StreamContent(new MemoryStream(content));
            }

            var response = new HttpResponseMessage(HttpStatusCode.OK)
            {
                Content = output
            };

            var mappedContentType = contentType ?? MimeMapping.GetMimeMapping(Path.GetExtension(filePath));
            response.Content.Headers.ContentType = new MediaTypeHeaderValue(mappedContentType);
            response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
            response.Content.Headers.ContentDisposition.FileName = fileName;

            return response;
        }, cancellationToken);
    }
}

您可以根据需要传入文件路径或字节流。

对于您的特定情况，您可以将Process.Start(localpath); 替换为：

return new FileResult(localpath, fileName, "application/octet-stream");

因此，您也不需要return Ok(response);。我看不到你的操作方法的签名，但它应该返回一个IHttpActionResult，或者如果你愿意，你可以直接指定FileResult作为返回类型。

（当然，如果您的文件有更准确的 MIME 类型信息，您应该使用它而不是“application/octet-stream”。）

Answer 2

我所做的只是将文件的完整路径从 Api 返回到 AngularJS 控制器，我正在使用条件

如果 (response.data.message != null) window.open('//'+response.data.message); 别的 alert("找不到文件！");

在消息部分，文件路径在那里。 这将在 Web 浏览器的新选项卡中打开文件。谢谢大家的支持 。学到了很多。