Extend the Coming-Soon page customizer options

[Kau-Boy]

As described in the blog post, I want to add a Customizer option to modify the introduction text: ​https://make.wordpress.org/community/2017/06/15/extend-the-coming-soon-page-customizer-options/

[coreymckrill]

@Kau-Boy this looks pretty good. Right now the sanitize_callback is sanitize_text_field, which strips out all HTML. It seems like we would want to be able to have some basic tags allowed so that organizers could, in the example of WCEU, link to the currently running camp. On the other hand, we don't want people dropping huge blocks of HTML into that space. What do you think?

[Kau-Boy]

@coreymckrill Oh yeah, you are right. Haven't seen that. I though allowing the HTML tags allowed by the wp_kses_data functions should be OK. How can this be set in the sanitize_callback argument?

[coreymckrill]

Hmm. I'll do some research to try and figure out what kind of sanitization needs to happen within textarea fields. It could be that wp_kses_data will work for there too, just like we have for the front end...

[Kau-Boy]

Looks good with the wp_kses_post filter for both input and output.

P.S. The attachment upload just added the file twice in a single request. Strange :/

[Kau-Boy]

I checked the current meta code and it seems like they all use wp_kses_post for the sanitize_callback.

[coreymckrill]

In 5603:

WordCamp Coming Soon: Add Customizer field for custom intro message

This adds a new setting and control to the Coming Soon Page section
in the Customizer. Content added to the Custom Message textarea will
replace the default message shown on the Coming Soon page beneath the
header. This allows organizers a bit more flexibility in what they
communicate to site visitors before the site is officially launched.

Fixes #2901
Props Kau-Boy

[coreymckrill]

@Kau-Boy thanks for the patch! I ended up going with a different approach for sanitizing the setting value for storage in the db (sanitize_callback). I looked at how textareas are sanitized in the Customizer in Core, namely menu item descriptions, and went with that. The Meta codebase doesn't always reflect the current best practices on some of these things, and I figured Core might be closer to that.

I also changed the label from "Introduction" to "Custom Message" and added a description because I thought it would make the purpose of the field more clear.

[Kau-Boy]

Thanks once again for the quick merge and improving my code ;) Nice sanitization callback. I will keep that for my other improvements to come :)

Now we should get the shortcode enhancements done ;) And then up to the invoicing :)