In AboutCertViewerHandler we can send an error message if something is wrong and we cannot send the certificate to about:certificate, this could be done with something like this:

aMessage.target.sendAsyncMessage("Error", {
  err: "There was an error",
});

And in the page, we can receive the error doing:

document.addEventListener("DOMContentLoaded", (e) => {
    RPMAddMessageListener("Error", showError);
});

function showError(message) {
  console.log("error ", message.data.err);
}

We need to handle all possible errors and show it in another way rather than console logging to the user.

This will probably need some coordination with Danielle to make sure we show some kind of UI to the user.

Maybe you can file a bug about creating the UI for errors? That way I can add here that bug blocking this one

Thanks

For the UI for errors, I'm currently creating a component that would conditionally render if there was an error.
That component would take up the full browser window, and would display an error message and image.

Should specific information about the error be displayed, or just a general 'error' message?

The call to create it could come from the "DOMContentLoaded" event listener in certviewer.js based on the response from RPMSendAsyncMessage("getCertificate"); (if I'm understanding that function correctly).

(In reply to danielleleb12 from comment #3)

Should specific information about the error be displayed, or just a general 'error' message?

I'm not sure yet, maybe we should ask Johann, but for the moment it could be a general error message, in my opinion.

https://treeherder.mozilla.org/#/jobs?repo=try&revision=2668cab42033b1d9cd0a5be0c298257c133b0596

Pushed by apavel@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/014889dc7434
Handles errors in about:certificate.r=keeler

https://hg.mozilla.org/mozilla-central/rev/014889dc7434

Backed out for causing high failure rate in Bug 1567161.

https://hg.mozilla.org/integration/autoland/rev/c5c6af9140705cc3d2b50352cc3d1f97da89bc32

The patch in https://bugzilla.mozilla.org/show_bug.cgi?id=1567161 fixed the error: https://treeherder.mozilla.org/#/jobs?repo=try&revision=2ed244cc9d55d4fe4963e30b284b0226c9f3f872

Pushed by apavel@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/b073b95fcf61
Handles errors in about:certificate.r=keeler

https://hg.mozilla.org/mozilla-central/rev/b073b95fcf61