Cannot publish the post using Gutenberg after changing REST URL prefix

[ibachal]

When I change REST URL prefix to something different "my-api" for example, using "rest_url_prefix" filter hook then it breaks the Gutenberg post save functionality because Gutenberg uses default "wp-json" REST URL prefix for API interactions.

Possible solution: Use "rest_get_url_prefix()" function to get URL prefix instead of "wp-json".

[TimothyBlynJacobs]

Hi @ibachal,

Could you share the code you are using to change the REST URL prefix? Gutenberg uses the createRootURLMiddleware to set the base URL of the REST API. The only ​hardcoded usages of wp-json I see in the repo are docs or test code.

[ibachal]

Hi @TimothyBlynJacobs

Thank you for looking into this. I am using the following code to change the REST URL prefix:

add_filter( 'rest_url_prefix', 'custom_rest_url_prefix' );
function custom_rest_url_prefix( $prefix ) {
 return 'api';
}

It changes default "wp-json" prefix to "api"

[TimothyBlynJacobs]

Where are you putting that code? Is it in any kind of conditional somewhere? I'm unable to replicate using that code.

[ibachal]

I am using this code in theme's functions.php file. I just retested and getting the same error.

[TimothyBlynJacobs]

I am using this code in theme's functions.php file.

Ah, I think that would be the issue, that is too late in the setup process. Try creating a ​site specific plugin or using the ​Snippets plugin and including your same code there.