Closes #5729 Refactor Cloudflare implementation

[remyperona]

Description

Refactor Cloudflare implementation

Fixes #5729

Type of change

• Enhancement (non-breaking change which improves an existing functionality)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[remyperona]

I found one case where the transient was incorrectly set early, I pushed a commit to fix this

[Mai-Saad]

@Tabrisrp We still have a problem on newlabs as follows now

• while caching everything off => an error is there WP Rocket: Missing Cloudflare Zone ID. Read the [documentation](https://docs.wp-rocket.me/article/18-using-wp-rocket-with-cloudflare/?utm_source=wp_plugin&utm_medium=wp_rocket#add-on) for further guidance.
• while caching everything on (excluding admin) => notice confirms changes at CF not displayed and changes not applied
  Please feel free to check it on newlabs (currently cache everything is off at CF) 🙏

[remyperona]

What are the steps for this case?

[Mai-Saad]

@CrochetFeve0251 Thanks for the update. The latest scenario is fixed, however, can see the following issues (working fine on trunk)
Scenario1:
1- Clear transients then fresh install and activation of wpr
2- Enable CF Addon and add valid keys along with enabling optimal settings in the same time then save => Error will be displayed while it shouldn't.
Scenario2:
1- Fresh install and activation of WPR
2- Enable CF and add valid keys
3- edit the public key and add some char then save => no error displayed
Can you please check this? 🙏

[vmanthos]

@CrochetFeve0251 Thank you for the update.

The scenario where saving the correct credentials after a fresh installation was causing an error is fixed. 🎉

However, both of the scenarios described by Mai in the previous comment are still there.

For the second one, the following notice is displayed:

Cloudflare cache level error: Incorrect Cloudflare Zone ID. Read the [documentation](https://docs.wp-rocket.me/article/18-using-wp-rocket-with-cloudflare/?utm_source=wp_plugin&utm_medium=wp_rocket#add-on) for further guidance.
Cloudflare minification error: Incorrect Cloudflare Zone ID. Read the [documentation](https://docs.wp-rocket.me/article/18-using-wp-rocket-with-cloudflare/?utm_source=wp_plugin&utm_medium=wp_rocket#add-on) for further guidance.
Cloudflare rocket loader error: Incorrect Cloudflare Zone ID. Read the [documentation](https://docs.wp-rocket.me/article/18-using-wp-rocket-with-cloudflare/?utm_source=wp_plugin&utm_medium=wp_rocket#add-on) for further guidance.
Cloudflare browser cache error: Incorrect Cloudflare Zone ID. Read the [documentation](https://docs.wp-rocket.me/article/18-using-wp-rocket-with-cloudflare/?utm_source=wp_plugin&utm_medium=wp_rocket#add-on) for further guidance.

Can you please look into these? 🙏

[piotrbak]

@vmanthos @Mai-Saad I'm not able to reproduce both scenarios :/

[piotrbak]

I can see the following edge case, which is not blocking. The same error as @vmanthos shared is displayed. Steps to reproduce:

1. Enable WP Rocket plugin and add correct CF credentials
2. Change credentials to the wrong ones and save settings - error is displayed about wrong credentials
3. Add back the correct credentials and save settings in the same step - error is displayed, the same as Vasilis mentioned

[vmanthos]

@piotrbak I checked the PR with the latest commits, and I can't reproduce scenario 2 but I can consistently do that for scenario 1.

Screencast in Slack Convo (non-public link).