[Bug]: Embedded PDF not displaying

[jannis6023]

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a bug report that matches the one I want to file, without success.

Electron Version

18.0.0

What operating system are you using?

macOS

Operating System Version

MacOS 12.3

What arch are you using?

x64

Last Known Working Electron version

No response

Expected Behavior

PDF File should be displayed just like when opening the page in Chrome browser.

Actual Behavior

The PDF file isn't displayed in the Embed.
Screenshot:

=> Error loading PDF document.

Testcase Gist URL

No response

Additional Information

I use this html for displaying it:
<embed type="application/pdf" src="https://....." style="width: 100%; height: 30rem;">
The document URL in here is a Blob URL with a PDF fetched from an internal API.

The window is loaded using this code:

const { app, BrowserWindow } = require('electron')
const createWindow = () => {
    const win = new BrowserWindow({
        width: 1400,
        height: 800,
        webPreferences: {
            plugins: true
        }
    })

    win.loadURL("https://127.0.0.1:8000/app")
}

app.whenReady().then(() => {
    createWindow()
})

[codebytere]

Bisected to v18.0.0-alpha.5...v18.0.0-beta.1

[lishid]

I have encountered the same issue with PDF files loaded from blob: URLs and custom:// file protocols. I have not been able to use file:/// protocols because of web security ("Not allowed to load local resource").

Related issue: #24859

[lishid]

Hmmm just reading the PR in #33560 it doesn't sound like the patch actually closes this specific issue.

Addresses a failure introduced by CL:3501416, whereby if a PDF failed to load: [...]
and a user then clicked the Reload button, the following error would be seen in console:
[...]
Notes: Fixed an issue where the PDF Viewer would fail if a user attempted to reload.

I don't have a way to test this until it's released but hopefully it actually fixes the broken PDF viewer for blob: URLs (and not just the Reload button).

[codebytere]

@lishid correct - it should be this one: #33664. I'll update the markings.

[sofianguy]

Fixed #33664

[george-thomas-hill]

@sofianguy :

I'm still finding (in Electron 21.2.0) that loading a PDF in an iFrame fails to display the PDF, and loading a PDF in a webview crashes Electron.

Here's an Electron Fiddle gist that demonstrates this:

https://gist.github.com/george-thomas-hill/c3179e6eddeb1a2715201a20dbf95015

Could you please take another look at this?