[Chrome] Service Workers
I was frustrated to discover a phantom service bound to port 8080.
If I browsed localhost:8080 in Chrome, I received a mostly blank screen that recalled when I’d used the WebThings gateway:
And the process responded to /metrics requests too:
I was flummoxed because I was not expecting this process to be running, could not find (and so could not kill it) and became concerned that it was something more nefarious:
sudo ss --tcp --listening \
| grep alt-http
sudo lsof -i :8080
sudo fuser 8080/tcp
Curiously Firefox and curl both (correctly) returned Connection refused errors.
When I opened the page in Chrome’s excellent Developer Tools, I noticed something curious:
Which led to Matt Gaunt’s Service Workers: An Introduction.
And this led me to the very useful DevTools Service Workers page:
chrome://inspect/#service-workers
Or via The Application tab on DevTools:
Which is perhaps chrome://serviceworker-internals/
Where I was able to uninstall it (and many others!) and now receive the expected response from Chrome when attempting to browse localhost:8080.
I am unfamiliar with Service Workers and assume they’re somewhat like cookies except as has been shown with the WebThings experience, they can be bound to localhost (ports) and behave like phantom processes.
Be careful out there!