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daisy / ace

Ace by DAISY, an Accessibility Checker for EPUB
MIT License
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Evaluation failed: DOMException: Blocked a frame with origin "null" from accessing a cross-origin frame. #358

Closed siddoib closed 2 years ago

siddoib commented 2 years ago

When running the latest daisy release v 1.2.3 I get the error message Evaluation failed: DOMException: Blocked a frame with origin "null" from accessing a cross-origin frame when a html page contains an iframe.

full details as below:

I am able to process the same epub file when using Ace v1.2.2 and below. I am also able to get at least a report when I run Ace v1.2.3 using Electron (ace-electron -V path/to/epub) even though I get the follwoing error messages the processing doesn't stop in constrast to running the default ace -V path/to/epub : electron: Failed to load URL: https://myIframe.com/htmlfile.htnl with error: ERR_BLOCKED_BY_CLIENT

danielweck commented 2 years ago

Hello, I wonder if this has anything to do with a previous (fixed) bug related to external iframe documents: https://github.com/daisy/ace/issues/339

I am not sure what could have triggered this bug from v1.2.2 to v1.2.3 !?

So, same request as before: may I please have a copy of your EPUB so I can attempt to reproduce the bug? Thank you :)

danielweck commented 2 years ago

Ah, I am able to reproduce the bug using 9780197545454_EPUB.epub which you shared with me via the previous bug report.

danielweck commented 2 years ago
siddoib commented 2 years ago

That's great - I was about to send another sample file. Yes, using the previous sample should trigger this error.

siddoib commented 2 years ago

I have come across the following axe-core issue and I am wondering it's not related to these ones. https://github.com/dequelabs/axe-core/pull/3096

danielweck commented 2 years ago

I fixed this bug via a patch to the DAISY fork of Axe. Both Ace's Electron and Puppeteer Axe "runners" yield identical validation reports, with the following execution time (reminder: external HTTP iframes are skipped / ignored):

./scripts/compareAxeRunners.sh 9780197545454_EPUB.epub

ElectronAxeRunner ...
>>> ACE PERF: 53 seconds + 447820398 nanoseconds
PuppeteerAxeRunner ...
>>> ACE PERF: 68 seconds + 522807222 nanoseconds
danielweck commented 2 years ago

DAISY Axe fork code reference: https://github.com/daisy/axe-core/blob/6b68cb184c532c8c7d14b1d00512b3df487d6588/lib/core/base/audit.js#L19-L29

Related API: https://www.deque.com/axe/core-documentation/api-documentation/#allowedorigins ...introduced in Axe v4.2.0: https://github.com/dequelabs/axe-core/blob/develop/CHANGELOG.md#420-2021-04-23

danielweck commented 2 years ago

Axe's getDefaultOrigin() returns "null" for file:// URLs which are used by Puppeteer (Ace's Electron Axe runner uses an HTTP server internally, thus why the problem doesn't surface in this case). Because Ace doesn't configure Axe with allowedOrigins, the getDefaultOrigin() value of "null" (which is not falsy, unlike null, obviously) automatically populates the array: https://github.com/daisy/axe-core/blob/6b68cb184c532c8c7d14b1d00512b3df487d6588/lib/core/base/audit.js#L47-L50 ...which causes a crash in window.postMessage(, origin): https://github.com/daisy/axe-core/blob/6b68cb184c532c8c7d14b1d00512b3df487d6588/lib/core/utils/frame-messenger/post-message.js#L41-L52 => Error: Failed to execute 'postMessage' on 'Window': Invalid target origin 'null' in a call to 'postMessage'

danielweck commented 2 years ago

This should be fixed in Ace 1.2.4, could you please update your local NPM install and confirm? Thank you very much, and thank you for bringing this to our attention! :)

https://github.com/daisy/ace/releases/tag/v1.2.4

siddoib commented 2 years ago

Good morning @danielweck. lastest version 1.2.4 of Ace tested and no iframes error reported in all my tests. Thank you so much for your help with this!