动态PDF并打开一个新窗口而不是下载

Question

我有一个web api，它将JSReport作为编码字节数组返回。无论我如何尝试读取字节数组，我都会得到一个黑屏或一条错误消息“无法下载pdf”。如果我创建一个隐藏的锚标签并下载pdf它工作正常。但是，我不希望用户下载它，我希望他们可以直接从浏览器中查看它。

WEB API CALL

   var data = LossReportService.GetLossSummary(request);
   var pdf_bytes = LossReportService.GeneratePDFUsingJSReport(data);

   byte[] myBinary = new byte[pdf_bytes.Length];
   pdf_bytes.Read(myBinary, 0, (int)pdf_bytes.Length);
   string base64EncodedPDF = System.Convert.ToBase64String(myBinary);

   var response = Request.CreateResponse(HttpStatusCode.OK, base64EncodedPDF);
   response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/pdf");
   response.Content.Headers.ContentLength = pdf_bytes.Length;

   return response;                  

使用Javascript

$.ajax({
    type: "POST",
    url: "/Reporting/GetLossSummary",
    data: { dataObj },
},
success: function (data) {
   if (data != null) {

    //I have tried this
    var file = new Blob([data], { type: 'application/pdf;base64' });
    var fileURL = URL.createObjectURL(file);
    window.open(fileURL, "LossSummaryReport");

    //which gives me a "failed to load pdf document" error

    //and I have tried this, which just renders a blank page
    window.open("data:application/pdf," + encodeURI(data)); 
  }
}
});

任何建议将不胜感激。

Answer 1

因为您正在使用jsreport，在正常情况下，您可以使用jsreport browser sdk更好地处理报告结果并在浏览器中轻松显示它。但在您的情况下，您在服务器中使用自定义URL来呈现报表，因此jsreport浏览器sdk在这种情况下无法帮助您。您需要使用jQuery ajax或纯XMLHttpRequest来处理报表请求和响应。

使用blob /二进制数据很难用jQuery.ajax来做，你需要add a data transport to $.ajax in order to handle binary data

/**
 *
 * jquery.binarytransport.js
 *
 * @description. jQuery ajax transport for making binary data type requests.
 * @version 1.0 
 * @author Henry Algus <[email protected]>
 *
 */

// use this transport for "binary" data type
$.ajaxTransport("+binary", function(options, originalOptions, jqXHR){
    // check for conditions and support for blob / arraybuffer response type
    if (window.FormData && ((options.dataType && (options.dataType == 'binary')) || (options.data && ((window.ArrayBuffer && options.data instanceof ArrayBuffer) || (window.Blob && options.data instanceof Blob)))))
    {
        return {
            // create new XMLHttpRequest
            send: function(headers, callback){
        // setup all variables
                var xhr = new XMLHttpRequest(),
        url = options.url,
        type = options.type,
        async = options.async || true,
        // blob or arraybuffer. Default is blob
        dataType = options.responseType || "blob",
        data = options.data || null,
        username = options.username || null,
        password = options.password || null;

                xhr.addEventListener('load', function(){
            var data = {};
            data[options.dataType] = xhr.response;
            // make callback and send data
            callback(xhr.status, xhr.statusText, data, xhr.getAllResponseHeaders());
                });

                xhr.open(type, url, async, username, password);

        // setup custom headers
        for (var i in headers ) {
            xhr.setRequestHeader(i, headers[i] );
        }

                xhr.responseType = dataType;
                xhr.send(data);
            },
            abort: function(){
                jqXHR.abort();
            }
        };
    }
});

但是当处理请求/响应中的blob数据时，我更喜欢直接使用XHTMLRequest，因为它让我以任何我想要的方式操纵响应。

function sendReportRequest (dataObj, cb) {
  var xhr = new XMLHttpRequest()
  var data = JSON.stringify(dataObj)

  xhr.open('POST', 'http://url-of-your-server/' + '/Reporting/GetLossSummary', true)
  xhr.setRequestHeader('Content-type', 'application/json; charset=utf-8')
  xhr.responseType = 'arraybuffer'

  xhr.onload = function () {
    if (this.status >= 200 && this.status < 300) {
      var response = xhr.response
      var contentType = xhr.getResponseHeader('Content-Type')
      var dataView = new DataView(response)
      var blob

      try {
        blob = new Blob([dataView], { type: contentType })
        cb(null, blob)
      } catch (e) {
        if (e.name === 'InvalidStateError') {
          var byteArray = new Uint8Array(response)
          blob = new Blob([byteArray.buffer], { type: contentType })
          cb(null, blob)
        } else {
          cb(new Error('Can not parse buffer response'))
        }
      }
    } else {
      var error = new Error('request failed')

      error.status = xhr.status
      error.statusText = xhr.statusText

      cb(error)
    }
  }

  xhr.onerror = function () {
    var error = new Error('request failed')

    error.status = xhr.status
    error.statusText = xhr.statusText

    cb(error)
  }

  xhr.send(data)
}

sendReportRequest(dataObj, function (err, reportBlob) {
  if (err) {
    return console.error(err)
  }

  var reportFileUrl = URL.createObjectURL(reportBlob)

  window.open(reportFileUrl)
})

使用这段代码，您应该能够请求pdf文件并在新窗口中将其显示在浏览器中