c# - WebAPI 返回损坏的、不完整的文件

Question

我想从 WebApi 端点返回图像。这是我的方法:

[System.Web.Http.HttpGet]
public HttpResponseMessage GetAttachment(string id)
{
    string dirPath = HttpContext.Current.Server.MapPath(Constants.ATTACHMENT_FOLDER);
    string path = string.Format($"{dirPath}\\{id}.jpg");

    try
    {
        HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
        var stream = new FileStream(path, FileMode.Open, FileAccess.Read);

        var content = new StreamContent(stream);
        result.Content = content;
        result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
        result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment") { FileName = Path.GetFileName(path) };
        return result;
    }
    catch (FileNotFoundException ex)
    {
        _log.Warn($"Image {path} was not found on the server.");
        return Request.CreateResponse(HttpStatusCode.NotFound, "Invalid image ID");
    }
}

很遗憾，下载的文件不完整。使用 Android 应用程序时的消息是:

java.io.EOFException: source exhausted prematurely

Answer 1

问题很可能是您的 Android 客户端认为下载已经结束，但实际上尚未结束。
要轻松解决此问题，您可以改用此方法，它会立即返回整个文件(而不是流式传输):

result.Content = new ByteArrayContent(File.ReadAllBytes(path));