从 ASP.NET ApiController 流式传输 Json 数据

Question

我正在尝试编写一个在响应中传输 JSON 数据的

ApiController

。事情是这样的；

public class MyController : ApiController
{
    IDocumentWriter _writer;

    public MyController(IDocumentWriter writer)
    {
        _writer = writer;
    }

    [HttpGet]
    public async Task<HttpResponseMessage> Get()
    {
        var response = Request.CreateResponse(HttpStatusCode.OK);

        using (var stream = new MemoryStream())
        {
            response.Content = new StreamContent(stream);
            await _writer.WriteAsync(stream);
            response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
            response.Content.Headers.ContentLength = stream.Length;
        }

        return response;
    }
}

IDocumentWriter

接受一个流并将 JSON 数据写入其中。对

Get

的调用失败，并显示

System.Threading.Tasks.TaskCanceledException

，我不明白，因为我正在等待

WriteAsync

。肯定是在返回之前写完吧？我做错了什么？

Answer 1

多亏了这篇文章，我才明白了这一点。事实证明我把事情复杂化了。这是最终的解决方案；

[HttpGet]
public async Task<HttpResponseMessage> Get()
{
    var response = Request.CreateResponse(HttpStatusCode.OK);

    response.Content = new PushStreamContent(async (stream, content, context) =>
    {
        await _writer.WriteAsync(stream);
        stream.Close();
    }, "application/json");

    return response;
}