Use path_info instead of path to match /_ping

path includes script_name which means that if an app's root is example.com/app, example.com/app/_ping won't work by default. Checking against path_info excludes the script name which means that it will check /_ping against the app root instead of the domain.

So if the app is hosted at app.example.com, app.example.com/_ping will work by default, and if the app is hosted at example.com/app, example.com/app/_ping will work by default as well.