如何使用 Web API 返回文件? [英] How to return a file using Web API?

问题描述

我正在使用 ASP.NET Web API.
我想从 API(API 生成)下载带有 C# 的 PDF.

I am using ASP.NET Web API.
I want to download a PDF with C# from the API (that the API generates).

我可以让 API 返回一个 byte[] 吗?对于 C# 应用程序，我可以这样做:

Can I just have the API return a byte[]? and for the C# application can I just do:

byte[] pdf = client.DownloadData("urlToAPI");? 

和

File.WriteAllBytes()?

推荐答案

最好返回包含 StreamContent 的 HttpResponseMessage.

Better to return HttpResponseMessage with StreamContent inside of it.

示例如下:

public HttpResponseMessage GetFile(string id)
{
    if (String.IsNullOrEmpty(id))
        return Request.CreateResponse(HttpStatusCode.BadRequest);

    string fileName;
    string localFilePath;
    int fileSize;

    localFilePath = getFileFromID(id, out fileName, out fileSize);

    HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
    response.Content = new StreamContent(new FileStream(localFilePath, FileMode.Open, FileAccess.Read));
    response.Content.Headers.ContentDisposition = new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment");
    response.Content.Headers.ContentDisposition.FileName = fileName;
    response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/pdf");

    return response;
}

UPD 来自 patridge 的评论:如果其他人想要从字节数组而不是实际文件发送响应，您将需要使用 new ByteArrayContent(someData) 而不是 StreamContent(请参阅 此处).

UPD from comment by patridge: Should anyone else get here looking to send out a response from a byte array instead of an actual file, you're going to want to use new ByteArrayContent(someData) instead of StreamContent (see here).

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