I’m trying to run the native messaging demo (as given in this MDN article on WebExtension native messaging) on a Windows 7 machine. I have Python 3.6.6 installed on that system and have copied the demo app files (the app manifest, the Python script and the batch file that runs the Python script) to C:\Users\username\Documents\native-msg-demo. I’ve added the Windows registry keys (HKEY_CURRENT_USER\SOFTWARE\Mozilla\NativeMessagingHosts\ping_pong) and set its value to the path to the location of the app manifest. The app manifest’s “path” property points to the .bat file.
But after I install the native messaging WebExtension in Firefox, I see the following error in the browser console:
Win error 5 during operation open on file C:\Users\username\Documents\native-msg-demo (Access is denied.)
I’ve already checked the “native-msg-demo” folder and confirmed that I have permissions to it. What else am I missing in my setup? Thanks in advance for any advice.