When/where does wasmUrl need to be set?

[jamesgurung]

I am using pdf.js from a CDN in a web application, to render PDF pages to a canvas (similar to the Hello World example). When upgrading to v5, is it necessary to set wasmUrl in this use case? If so, how/where do I set it?

[bobzel]

I think I'm having a similar issue:
import 'pdfjs-dist/webpack.mjs';

no longer works because it can't find qcms_wasm

[jamesgurung]

@Snuffleupagus @calixteman Please could you advise on this? I've been holding off updating to v5 because I'm a bit unclear on this change.

Is the Hello World example still up to date, or would it need changing to add wasmUrl?

[denydias]

I'm in the same situation as you and @bobzel: holding on to v4 as there is no clear indication on how to implement this new wasmUrl option, while webpack complains about it. None of the pdfjs examples clarifies this change.

EDIT: some reference here.

[denydias]

Ok! Dove into it today. Here's what I've found:

@jamesgurung:

I am using pdf.js from a CDN in a web application, to render PDF pages to a canvas (similar to the Hello World example). When upgrading to v5, is it necessary to set wasmUrl in this use case? If so, how/where do I set it?

If you are just using the default web viewer, most probably no as it loads viewer.mjs that already sets wasmUrl. But if you're loading the worker yourself, then keep reading.

@bobzel:

I think I'm having a similar issue:
import 'pdfjs-dist/webpack.mjs';
no longer works because it can't find qcms_wasm

This is related to #19761 and #19801. ATM loading the v5 worker through webpack is broken. To work around it, you should replace this:

import * as pdfjsLib from 'pdfjs-dist/webpack.mjs';

const pdfUrl = '/your/public/file.pdf';

pdfjsLib.getDocument(pdfUrl);

With this:

import * as pdfjsLib from 'pdfjs-dist';
import pdfWorkerURL from 'file-loader!pdfjs-dist/build/pdf.worker.mjs';

pdfjsLib.GlobalWorkerOptions.workerPort = new Worker(pdfWorkerURL, { type: 'module' });

const pdfUrl = '/your/public/file.pdf',
      wasmUrl = '/your/public/pdfjs/web/wasm/';

pdfjsLib.getDocument({url: pdfUrl, wasmUrl: wasmUrl});

This is a workaround! It should be reverted when pdfjs-dist webpack bundling gets fixed to deal with the module URLs in a proper way. If you don't understand or feel safe with the workaround, just stick with v4 for a while.

[denydias]

This is a workaround! It should be reverted when pdfjs-dist webpack bundling gets fixed to deal with the module URLs in a proper way. If you don't understand or feel safe with the workaround, just stick with v4 for a while.

PDF.js v5.2.133 is out with #19810 fixing webpack handling. The workaround above can now be dropped. The following code can handle PDF.js compiling/loading just fine with wasmUrl declared:

import * as pdfjsLib from 'pdfjs-dist/webpack.mjs';