Flash SWF content not correctly loaded in Electron 7

[frankieta]

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 an issue that matches the one I want to file, without success.

Issue Details

• Electron Version:
  • 7.0.0
• Operating System:
  • Windows 10 (1803)
• Last Known Working Electron version:
  • 6.1.2

Expected Behavior

Loading flash content through an swf file results in the correct visualization of said content

Actual Behavior

An error "GET http://interactive-mirror3.nfb.ca/FrameLoader.swf net::ERR_INVALID_ARGUMENT" appears:

To Reproduce

Try embedding this flash website in an electron project (http://bear71.nfb.ca/#/bear71) following this tutorial: https://electronjs.org/docs/tutorial/using-pepper-flash-plugin

Screenshots

Additional Information

[GhostlyDark]

Introduced with v7.0.0-beta.4

[georgelesica-wf]

This also seems to manifest on Mac.

[ncodeyx]

Confirmed on Windows and Mac.

[misbeliever]

Same in 7.1.2 :(

[eric-zhangqi]

some in 7.1.2 not in 6.0.7

[misbeliever]

Same in 8.0.0-beta.3

[lovoror]

Same in 8.0.0-beta.3 and 7.1.2

[kkannan-carecloud]

Anyone here know which version of electron supports flash in MacOS ?

[Rosslington]

This is also still broken in 7.1.3

[kkannan-carecloud]

If someone here is looking for the last version known to work with flash, it will be 6.1.2

[GhostlyDark]

Anything before v7 works. v7 and after are broken, since the bug was patched into master.

[Tackyou]

The last version it works with is 7.0.0-beta.3, in beta.4 they updated chromium which broke it.

[GhostlyDark]

Could that Chromium commit be the cause?
https://chromium.googlesource.com/chromium/src/+/e3e480e63aca01cc7d3c0be286b7721a63cbe1d3

[GhostlyDark]

Using flash version 32.0.0.270 does not work.

[t57ser]

Using flash version 32.0.0.270 does not work.

Can confirm, I also tried and it did not work

[Tackyou]

Did you use 7.0.0-beta3 ?
Any higher version doesn’t work no matter which pepperflash version.

[GhostlyDark]

7.0.0-beta.3 and earlier will work with pretty much any flash version, including 32.0.0.303.

[fp07]

Any updates? Workaround? The last working version is 6.1.2 for flash 32.0.0.238.

[Tackyou]

7.0.0-beta.3 and earlier will work with pretty much any flash version, including 32.0.0.303.

You're right there was a mistake in my code.

[fp07]

Updates?

[lkonstantinov]

The problem has nothing to do with the sandboxing problem suggested in #20309. It is actually caused by a bad header :)

Chromium added more complex CORS handling that required consumers (like Electron) to register list of 'safe' headers that are exempt from the CORS process. One such header is X-Requested-With which is injected by the Flash plugin.

Since that change is missing in Electron, the CORS handler is rejecting the request (because it has an unrecognized header) and you get the net::ERR_INVALID_ARGUMENT error.

The fix is to amend SystemNetworkContextManager::CreateDefaultNetworkContextParams() in electron\shell\browser\net\system_network_context_manager.cc to reflect the chrome\browser\net version by adding (with the corresponding includes):

  content::UpdateCorsExemptHeader(network_context_params.get());
  variations::UpdateCorsExemptHeaderForVariations(network_context_params.get());

For more info - check out the relevant Chromium ticket - https://bugs.chromium.org/p/chromium/issues/detail?id=940331

[Tinysymphony]

Same in 7.1.7

[JeimeRhee]

Same in v7.1.9

[JeimeRhee]

I edited electron "system_network_context_manager.cc" as @lkonstantinov said and electron build succeed.

I want to testing this electron module embedding on my local project, but I don't know how to change modified electron module to local npm packages...

Can anyone help me?

[lkonstantinov]

@JeimeRhee - you can repack electron (instructions are on the build page here - https://electronjs.org/docs/development/build-instructions-gn ) and then just replace it I guess.

[t57ser]

@JeimeRhee you don't need to use it as an npm module, you can use the build version in /out and just modify the asar. Use:
npx asar extract default_app.asar some_folder_name
modify the files and pack it again via:
npx asar pack some_folder_name default_app.asar

[JeimeRhee]

@lkonstantinov Thx for reply. I'm sorry to late checked your reply.
I already read build instruction and try to packaging but when I execute
ninja -C out/Release electron:electron_dist_zip
it always print out "ninja no work to do." messages...
My build environment is Windows 10 is that command only working on linux environment?

[fp07]

Someone an tutorial how to apply the fix?

[kyle-mcknight]

Why a tutorial on how to apply a fix rather than a fix being committed? I'd really rather not build a custom version of Electron to use in production code where we are dealing with taking people's money

[kyle-mcknight]

This does work in Electron 6.1.7 (32bit at least).

[andreieftimie]

Can this be prioritized for a fix?

We're reverting to Electron 6 as our app still requires flash for some (old) functionality which we can't yet deprecate.

[fp07]

Can this be prioritized for a fix?

We're reverting to Electron 6 as our app still requires flash for some (old) functionality which we can't yet deprecate.

Indeed

[t57ser]

I've managed to build this locally and can confirm the fix is working. If anyone needs to fix this manually before it gets released you can check out the pull request (#22072) for the required changes.