请求正文字符显示？使用快速书中的提取或请求

Question

我正在节点10.16环境中使用quickbooks api。我正在尝试通过API获取PDF。

我得到的是看起来正确的响应，但是当我打开它时显示为空白

我直接使用邮递员下载了一个文件，该文件有效。

我已经使用记事本++打开了两个文件，我可以看到文件上的某些字符有吗？或一个正方形，在邮递员文件上我看到一个字符。

This google folder has both files

这是主要代码，我使用fetch从API中获取信息

      return fetch(url, fetchOptions).then((response) => {
        if (response.ok) {
            return response.text()
        }

response.text（）是发生错误解码的地方，因为我已将其直接保存到文件中，或者尝试使用TextDecoder对其进行解码，并且它始终会给我带来不良字符。

这是我到目前为止测试过的内容

            return response.arrayBuffer().then(buffer => {
              let decodedValue = new util.TextDecoder('utf-8').decode(buffer)
              fs.writeFile('decodetest.pdf', decodedValue, (err) => {
                // throws an error, you could also catch it here
                if (err) throw err;

                // success case, the file was saved
                console.log('decode file saved!');
              });
              return decodedValue;
            });

rp以下使用的是不同的程序包响应承诺。也给出相同的结果。

      return rp(options)
          .then(function (response) {
              console.log("Did a new response");
              response.body
              fs.writeFile('requesttest.pdf', response.body, (err) => {
                // throws an error, you could also catch it here
                if (err) throw err;

                // success case, the file was saved
                console.log('request test file saved!');
              });
          })
          .catch(function (err) {
              // Delete failed...
          });

Answer 1

我假设您要在浏览器中显示文件。我会为此使用3rd party库。这是直接来自Mozilla pdf.js文档的代码，对我来说显示来自Express服务器的.pdf文件效果很好。更改'url'变量以指向要渲染的pdf，我已经注释掉了，但是会附加一个gif，以显示它的渲染方式：

/ public / javascripts / main.js

// If absolute URL from the remote server is provided, configure the CORS
// header on that server.
var url = 'https://raw.githubusercontent.com/mozilla/pdf.js/ba2edeae/web/compressed.tracemonkey-pldi-09.pdf';

// var url = '/test.pdf';

// Loaded via <script> tag, create shortcut to access PDF.js exports.
var pdfjsLib = window['pdfjs-dist/build/pdf'];

// The workerSrc property shall be specified.
pdfjsLib.GlobalWorkerOptions.workerSrc = '//mozilla.github.io/pdf.js/build/pdf.worker.js';

var pdfDoc = null,
    pageNum = 1,
    pageRendering = false,
    pageNumPending = null,
    scale = 0.8,
    canvas = document.getElementById('the-canvas'),
    ctx = canvas.getContext('2d');

/**
 * Get page info from document, resize canvas accordingly, and render page.
 * @param num Page number.
 */
function renderPage(num) {
  pageRendering = true;
  // Using promise to fetch the page
  pdfDoc.getPage(num).then(function(page) {
    var viewport = page.getViewport({scale: scale});
    canvas.height = viewport.height;
    canvas.width = viewport.width;

    // Render PDF page into canvas context
    var renderContext = {
      canvasContext: ctx,
      viewport: viewport
    };
    var renderTask = page.render(renderContext);

    // Wait for rendering to finish
    renderTask.promise.then(function() {
      pageRendering = false;
      if (pageNumPending !== null) {
        // New page rendering is pending
        renderPage(pageNumPending);
        pageNumPending = null;
      }
    });
  });

  // Update page counters
  document.getElementById('page_num').textContent = num;
}

/**
 * If another page rendering in progress, waits until the rendering is
 * finised. Otherwise, executes rendering immediately.
 */
function queueRenderPage(num) {
  if (pageRendering) {
    pageNumPending = num;
  } else {
    renderPage(num);
  }
}

/**
 * Displays previous page.
 */
function onPrevPage() {
  if (pageNum <= 1) {
    return;
  }
  pageNum--;
  queueRenderPage(pageNum);
}
document.getElementById('prev').addEventListener('click', onPrevPage);

/**
 * Displays next page.
 */
function onNextPage() {
  if (pageNum >= pdfDoc.numPages) {
    return;
  }
  pageNum++;
  queueRenderPage(pageNum);
}
document.getElementById('next').addEventListener('click', onNextPage);

/**
 * Asynchronously downloads PDF.
 */
pdfjsLib.getDocument(url).promise.then(function(pdfDoc_) {
  pdfDoc = pdfDoc_;
  document.getElementById('page_count').textContent = pdfDoc.numPages;

  // Initial/first page rendering
  renderPage(pageNum);
});

/ views / index.ejs

<!DOCTYPE html>
<html>
  <head>
    <title>Express PDF Example</title>
  </head>
  <body>
    <script src="//mozilla.github.io/pdf.js/build/pdf.js"></script>
    <h1>PDF.js Previous/Next example</h1>
    <div>
      <button id="prev">Previous</button>
      <button id="next">Next</button>
      &nbsp; &nbsp;
      <span>Page: <span id="page_num"></span> / <span id="page_count"></span></span>
    </div>
    <canvas id="the-canvas"></canvas>
    <script type="text/javascript" src="/javascripts/main.js"></script>
  </body>
</html>

这里是我的gif图像，我使用的是带有Mozilla提供的URL的库以及本地计算机上的pdf：