Nonce Middleware: Wrap the nonce middleware function into it's own function.

[dd32]

Description

The nonce middleware function is re-generated on every API call, which is causing the initial nonce to always be used and the addAction() to be queued up multiple times.

Splitting this up and returning a function here solves both of the problems, and should fix #9260

How has this been tested?

To test, Set the nonce_life to 60s and have heartbeat run every 20s.
Use the editor for >2minutes (Switching images around works), you shouldn't encounter update failed messages, and the console should be clear.

add_filter( 'nonce_life', function() { return 60; } );

add_filter( 'heartbeat_settings', function( $settings ) { $settings['interval'] = 20; return $settings; } );

[earnjam]

I'll defer to @youknowriad since he wrote this code initially, but just wanted to note this is working well for me and appears to resolve the nonce issue.

It also stopped the hook from firing multiple times per heartbeat tick. Without this patch I was seeing it firing ~7 times per tick after just an initial load of the editor and not doing anything.

[youknowriad]

The nonce middleware function is re-generated on every API call, which is causing the initial nonce to always be used and the addAction() to be queued up multiple times.

I don't think the middleware function was regenerated by each API call, I'd say, the hook function was which is not great indeed.

[youknowriad]

Code changes look good to me 👍 And since others have tested, let's ship.

[danielbachhuber]

Thanks @dd32 !