1822696 - webRequest.onBeforeRequest isn't triggered at all for clicked links in email message

Status: RESOLVED WORKSFORME

(Thunderbird :: Add-Ons: Extensions API, defect)

Description

[Marcin Zajaczkowski]

Attachment: Simple extension reproducing a problem

Steps to reproduce:

TL;TR:

1. Write a simple extension with a listener on browser.webRequest.onBeforeRequest.
2. Click any HTTP(S) link in an email message.

Longer description:
I was missing an add-on to whitelist clickable URLs to mitigate (spear)phishing attacks (see at the end for the reasons), so I wanted to write my own. Using the hello world tutorial in the Thunderbird documentation, I was able to write one, however, I hit the problem with not triggered "webRequest.onBeforeRequest".

When I load the extension in the debug mode, it is loaded, "initialization" is print. Unfortunately, when I click any http/https link in my email (which are open in Firefox), nothing is caught by the callback.

I also tried "webNavigation.onBeforeNavigate" which works. However, I need the real URL not "mailbox:///home/foobar/.thunderbird/abcd.default/Mail/example.com/Inbox?number=1234".

I attached a simple extension to reproduce the problem.

Here's a thread when I originally described the problem and I've got a suggestion from John Bieling to report a bug to get it fixed in Thunderbird:
https://thunderbird.topicbox.com/groups/addons/T37675249e8aa089e/webrequest-onbeforerequest-isnt-triggered-at-all

Actual results:

The listener is not called. Not at all.

Expected results:

The listener is called and it is possible to do some actions (e.g. block blacklisted domains).

Comment 1

[John Bieling]

The webRequest is not handled by Thunderbird. It is forwarded to your default Browser, for example Firefox. The add-on to manipulate the request needs to be loaded into that browser.

We deliberately do not handle such links on our own (and open them within Thunderbird).

However, there is an add-on which changes that behaviour:
https://addons.thunderbird.net/addon/browseintab/

If you install that, you will see the webRequest being handled by Thunderbird.