ASP.NET WebAPI에서 파일 (FileContentResult)을 반환하는 방법

ASP.NET WebAPI에서 파일 (FileContentResult)을 반환하는 방법

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일반 MVC 컨트롤러에서는을 사용하여 pdf를 출력 할 수 있습니다 FileContentResult.

public FileContentResult Test(TestViewModel vm)
{
    var stream = new MemoryStream();
    //... add content to the stream.

    return File(stream.GetBuffer(), "application/pdf", "test.pdf");
}

그러나 어떻게 그것을로 바꿀 수 ApiController있습니까?

[HttpPost]
public IHttpActionResult Test(TestViewModel vm)
{
     //...
     return Ok(pdfOutput);
}

---

여기에 내가 시도한 것이 있지만 작동하지 않는 것 같습니다.

[HttpGet]
public IHttpActionResult Test()
{
    var stream = new MemoryStream();
    //...
    var content = new StreamContent(stream);
    content.Headers.ContentType = new MediaTypeHeaderValue("application/pdf");
    content.Headers.ContentLength = stream.GetBuffer().Length;
    return Ok(content);            
}

브라우저에 표시되는 결과는 다음과 같습니다.

{"Headers":[{"Key":"Content-Type","Value":["application/pdf"]},{"Key":"Content-Length","Value":["152844"]}]}

그리고 비슷한 게시물이 있습니다 : ASP.NET Web API의 컨트롤러에서 바이너리 파일 반환 . 기존 파일 출력에 대해 설명합니다. 그러나 스트림으로 작동시키지 못했습니다.

어떤 제안?

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대신에 반환하는 StreamContent으로 Content, 나는 그것이 작동 할 수 있습니다 ByteArrayContent.

[HttpGet]
public HttpResponseMessage Generate()
{
    var stream = new MemoryStream();
    // processing the stream.

    var result = new HttpResponseMessage(HttpStatusCode.OK)
    {
        Content = new ByteArrayContent(stream.ToArray())
    };
    result.Content.Headers.ContentDisposition =
        new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment")
    {
        FileName = "CertificationCard.pdf"
    };
    result.Content.Headers.ContentType =
        new MediaTypeHeaderValue("application/octet-stream");

    return result;
}

---

돌아가려면 IHttpActionResult다음과 같이하십시오.

[HttpGet]
public IHttpActionResult Test()
{
    var stream = new MemoryStream();

    var result = new HttpResponseMessage(HttpStatusCode.OK)
    {
        Content = new ByteArrayContent(stream.GetBuffer())
    };
    result.Content.Headers.ContentDisposition = new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment")
    {
        FileName = "test.pdf"
    };
    result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");

    var response = ResponseMessage(result);

    return response;
}

---

이 질문이 도움 이 되었습니다.

따라서 이것을 시도하십시오 :

컨트롤러 코드 :

[HttpGet]
public HttpResponseMessage Test()
{
    var path = System.Web.HttpContext.Current.Server.MapPath("~/Content/test.docx");;
    HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
    var stream = new FileStream(path, FileMode.Open);
    result.Content = new StreamContent(stream);
    result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
    result.Content.Headers.ContentDisposition.FileName = Path.GetFileName(path);
    result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
    result.Content.Headers.ContentLength = stream.Length;
    return result;          
}

클릭 이벤트 및 간단한 URL과 함께 HTML 마크 업보기 :

<script type="text/javascript">
    $(document).ready(function () {
        $("#btn").click(function () {
            // httproute = "" - using this to construct proper web api links.
            window.location.href = "@Url.Action("GetFile", "Data", new { httproute = "" })";
        });
    });
</script>


<button id="btn">
    Button text
</button>

<a href=" @Url.Action("GetFile", "Data", new { httproute = "" }) ">Data</a>

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I am not exactly sure which part to blame, but here's why MemoryStream doesn't work for you:

As you write to MemoryStream, it increments it's Position property. The constructor of StreamContent takes into account the stream's current Position. So if you write to the stream, then pass it to StreamContent, the response will start from the nothingness at the end of the stream.

There's two ways to properly fix this:

1) construct content, write to stream

[HttpGet]
public HttpResponseMessage Test()
{
    var stream = new MemoryStream();
    var response = Request.CreateResponse(HttpStatusCode.OK);
    response.Content = new StreamContent(stream);
    // ...
    // stream.Write(...);
    // ...
    return response;
}

2) write to stream, reset position, construct content

[HttpGet]
public HttpResponseMessage Test()
{
    var stream = new MemoryStream();
    // ...
    // stream.Write(...);
    // ...
    stream.Position = 0;

    var response = Request.CreateResponse(HttpStatusCode.OK);
    response.Content = new StreamContent(stream);
    return response;
}

2) looks a little better if you have a fresh Stream, 1) is simpler if your stream does not start at 0

---

Here is an implementation that streams the file's content out without buffering it (buffering in byte[] / MemoryStream, etc. can be a server problem if it's a big file).

public class FileResult : IHttpActionResult
{
    public FileResult(string filePath)
    {
        if (filePath == null)
            throw new ArgumentNullException(nameof(filePath));

        FilePath = filePath;
    }

    public string FilePath { get; }

    public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        var response = new HttpResponseMessage(HttpStatusCode.OK);
        response.Content = new StreamContent(File.OpenRead(FilePath));
        var contentType = MimeMapping.GetMimeMapping(Path.GetExtension(FilePath));
        response.Content.Headers.ContentType = new MediaTypeHeaderValue(contentType);
        return Task.FromResult(response);
    }
}

It can be simply used like this:

public class MyController : ApiController
{
    public IHttpActionResult Get()
    {
        string filePath = GetSomeValidFilePath();
        return new FileResult(filePath);
    }
}

---

For me it was the difference between

var response = Request.CreateResponse(HttpStatusCode.OK, new StringContent(log, System.Text.Encoding.UTF8, "application/octet-stream");

and

var response = Request.CreateResponse(HttpStatusCode.OK);
response.Content = new StringContent(log, System.Text.Encoding.UTF8, "application/octet-stream");

The first one was returning the JSON representation of StringContent: {"Headers":[{"Key":"Content-Type","Value":["application/octet-stream; charset=utf-8"]}]}

While the second one was returning the file proper.

It seems that Request.CreateResponse has an overload that takes a string as the second parameter and this seems to have been what was causing the StringContent object itself to be rendered as a string, instead of the actual content.

참고URL : https://stackoverflow.com/questions/26038856/how-to-return-a-file-filecontentresult-in-asp-net-webapi