无法将自定义标头从WebAPI公开给客户端 [英] Not able to expose the custom headers from WebAPI to client

问题描述

我编写了一个程序来下载Web api返回的pdf，word或txt文件，并且工作正常.在服务器端，我使用了WebApi和客户端AngularJs.现在的问题是，我还需要api的文件名，为此，我需要读取api返回的标头.但是reponse.headers并不包含所有标题信息.下面是我的代码:

I have written a program to download the pdf, word or txt file returned by web api and it's working fine. On server side I have used WebApi and client side AngularJs. Now the problem is, I also need the file name from api as well and for that I need to read the headers returned by api. But reponse.headers doesn't contains all the headers info. Below is my code:

 [HttpGet]
 [Authorize]
    public HttpResponseMessage GetTranscript(string key, int format)
    {
        var badRequest = Request.CreateResponse(HttpStatusCode.OK, "Not a valid input."); //ResponseMessage(Request.CreateResponse(HttpStatusCode.BadRequest, "Not a valid input."));
        if (string.IsNullOrWhiteSpace(jiraTaskKey))
        {
            return badRequest;
        }

        string transcript = _mediaCaptionService.GetTranscript(UserId, key);

        string fileName = "transcript";
        var response = new HttpResponseMessage(HttpStatusCode.OK);

        if (format == (int)TranscriptFormat.PDF)
        {
            byte[] byteInfo = GeneratePDFTranscript(transcript);
            response.Content = new ByteArrayContent(byteInfo);
            response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
            fileName = fileName + ".pdf";
        }
        else if (format == (int)TranscriptFormat.TXT)
        {
            response.Content = new StringContent(transcript, System.Text.Encoding.UTF8, "text/plain");
            fileName = fileName + ".txt";
        }
        else if (format == (int)TranscriptFormat.WORD)
        {                
            string transcriptFontName = "Arial";
            byte[] byteInfo = GenerateWordTranscript(transcript, transcriptFontName);
            response.Content = new ByteArrayContent(byteInfo);
            response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
            fileName = fileName + ".doc";
        }
        else
        {
            return badRequest;
        }
        response.Content.Headers.Add("x-filename", fileName);
        response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment") {
            FileName = fileName
        };
        //response.Content.Headers.ContentDisposition.FileName = fileName;
        return response; //ResponseMessage(response);
    }      

并在客户端

  function getTranscriptResult(method, apiUrl, data) {
        var deferred = $q.defer();
        $http({
            method: method,
            url: apiUrl,
            data: data,
            responseType: 'arraybuffer'

        }).success(function (data, status, headers, config) {
            debugger;
            var results = [];
            results.data = data;
            results.headers = headers();
            results.status = status;
            results.config = config;                
            deferred.resolve(results);

        }).error(function (error, status, headers, config) {
            deferred.reject(error);

        });
        return deferred.promise;
    }

但是当我在上面的代码中放置断点时，我得到了:

But when I put the break point in above code, I get this:

您能告诉我代码中哪里找不到文件名的问题吗?另外，如果您需要更多信息，请告诉我.

Can you please tell me where is the problem in my code that I am not able to get the file name? Also please let me know if you need more information.

推荐答案

添加以下几行后，解决了我的问题.

After adding below lines has solved my problem.

// Add a custom header for filename and expose it to be consumed by JavaScript.
response.Content.Headers.Add("Filename", zipFileName);
response.Content.Headers.Add("Access-Control-Expose-Headers", "Filename");

因此，基本上添加 Access-Control-Expose-Headers 有助于我将自定义标头公开给客户端.有关此的更多信息，请遵循以下链接

So basically adding Access-Control-Expose-Headers helped me to expose the custom headers to client. For more information on this please follow this link

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