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onError handler doesn't work

See original GitHub issue

I’m trying to print a PDF from the server. If a server error occurs, I want to display this error in the UI, for this, I try to use the onError handler, but it does not work, my function is not called.

      printable: "docs/myFile.pdf",
      type: 'pdf',
      showModal: true,
      onError: err => console.log("Erorr") // it doesn't work

What am I doing wrong?

Issue Analytics

  • State:closed
  • Created 5 years ago
  • Comments:14 (7 by maintainers)

github_iconTop GitHub Comments

crabblycommented, Apr 3, 2019

Hey guys, this change is now available with the latest version. Run npm update print-js to get it.

Let me know of any issues. Thank you.

harpsicord86commented, Dec 12, 2018

Hi @crabbly @yaroslav-perec

I may have a fix for you as I’ve had the same issue. Basically in pdf.js if you check that the specified URL exists first and encapsulate the rest of the method in a try clause, you can then set params.onError to trigger. Here is some code:

function UrlExists(url) { var http = new XMLHttpRequest();'HEAD', url, false); http.send(); if (!(http.status >= 200 && http.status < 300 || http.status === 304)) { throw new Error(http.statusText); } }

`exports.default = { print: function print(params, printFrame) { // Format pdf url params.printable = /^(blob|http)/i.test(params.printable) ? params.printable : window.location.origin + (params.printable.charAt(0) !== ‘/’ ? ‘/’ + params.printable : params.printable); try { UrlExists(params.printable);

      // If showing a loading modal or using a hook function, we will preload the pdf file
      if (params.showModal || params.onLoadingStart) {
          // Get the file through a http request
          var req = new window.XMLHttpRequest();
          req.responseType = 'arraybuffer';

          req.addEventListener('load', function () {
              // Pass response data to a blob and create a local object url
              var localPdf = new window.Blob([req.response], { type: 'application/pdf' });
              localPdf = window.URL.createObjectURL(localPdf);

              // Pass the url to the printable parameter (replacing the original pdf file url)
              // This will prevent a second request to the file (server) once the iframe loads
              params.printable = localPdf;

              send(params, printFrame);

'GET', params.printable, true);
      } else {
          send(params, printFrame);
  } catch (e) {

} };`

Also, I found an issue with the modal appearing after the error message appears (this is at the point where the script checks for the printable type) - this also needs to be encapsulated in a try clause:

// Check printable type switch (params.type) { case 'pdf': // Check browser support for pdf and if not supported we will just open the pdf file instead if (_browser2.default.isFirefox() || _browser2.default.isEdge() || _browser2.default.isIE()) { try {'PrintJS currently doesn\'t support PDF printing in Firefox, Internet Explorer and Edge.'); var win =, '_blank'); win.focus(); if (params.onPdfOpen) params.onPdfOpen(); } catch (e) { params.onError(e); } finally { // Make sure there is no loading modal opened if (params.showModal) _modal2.default.close(); if (params.onLoadingEnd) params.onLoadingEnd(); } } else { try { _pdf2.default.print(params, printFrame); } catch (e) { params.onError(e); } finally { // Make sure there is no loading modal opened if (params.showModal) _modal2.default.close(); if (params.onLoadingEnd) params.onLoadingEnd(); } } break; case 'image': _image2.default.print(params, printFrame); break; case 'html': _html2.default.print(params, printFrame); break; case 'json': _json2.default.print(params, printFrame); break; }

I hope this helps with your next version and to anyone else wanting to solve this issue!


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