Conditional function that lets you know if your site is being viewed through the Customizer

[nathanrice]

I can provide a use case if necessary, but this should be relatively simple.

If I need to do something special with my theme when my site is being viewed through the customizer, there's no easy way determine if it is.

A simple is_customizer() (or similar) function would be incredibly useful in this scenario.

I'd write up a patch, but I don't know where to put the new function.

[SergeyBiryukov]

This seems to work for me:

global $wp_customize;
if ( isset( $wp_customize ) ) {
	// ...
}

[sammybeats]

Submitted a patch that creates a function is_customizer() that checks to make sure $wp_customize is of type WP_Customize_Manager and returns the value of $wp_customize->is_preview();

[SergeyBiryukov]

Related: #25104

[ScottSmith]

Is it possible to push for this to be added to the WordPress 3.7 milestone?

[mattwiebe]

I've refreshed and simplified the patch. We've been running this on WordPress.com since April and we should land it in 3.8.

[ocean90]

Replying to nathanrice:

I can provide a use case if necessary

Can you please?

[nathanrice]

mattwiebe mentioned that they're using this on WordPress.com. He can probably provide a much more compelling use-case than I could.

[mattwiebe]

Here's some use cases from WP.com:

• Custom Fonts in the Customizer - we use a Typekit kit on a non-Customizer view, but all font rendering happens via a preview script in the Customizer. We use is_customizer() to decide which should be enqueued.
• Stylesheet concatenation - turn off in the Customizer for Custom CSS users so that we can identify the specific stylesheet and remove it when the user edits their stylesheet.
• don't load stats scripts in the customizer

There's a few more that aren't as easy to explain.

[ocean90]

Thanks mattwiebe.

is_customizer seems like a fine name, but isn't it more is_customize_preview?

[mattwiebe]

Replying to ocean90:

Thanks mattwiebe.

is_customizer seems like a fine name, but isn't it more is_customize_preview?

Both have some ambiguity. I've always thought is_previewing bit of the Customizer seems a bit weird when you're not previewing a non-active theme, at least not at first.

I actually think in_customizer is a bit clearer but most of our conditionals go with is_*.

[obenland]

Keep in mind we also have ​is_preview() for post previews.

[celloexpressions]

I would suggest either is_customize, is_customizing or is_customize_preview. It's the customize preview in the sense that you're previewing the changes you're making to different settings, regardless of whether or not it's a theme preview.

In code, everything's customize, not customizer. However, considering the customizer as the thing and customize as the action, is_customizing could also make sense. But is_customize_preview is probably our best option here, all things considered.

[SergeyBiryukov]

In 28999:

Add is_customize_preview(), a conditional function to check if the site is being previewed in the Customizer.

props sammybeats, mattwiebe.
fixes #23509.