虽然不能使用Wordpress API，但可以使用vanilla PHP轻松完成。

<?php
//Get the full path of the local directory first.
$fullpath = __DIR__;

//check if you are in a theme directory or a plugin directory
if (strpos( $fullpath, \'themes\' ) !== false )
{
    //It\'s a theme, use get_stylesheet_uri

} elseif ( strpos( $fullpath, \'plugins\' )
{
    //It\'s a plugin, use plugins_url

} else {
    //It\'s somewhere else entirely.
}

I found myself in the same situation, I\'m developing a library that I don\'t know where will it be included by other users, so I cannot provide an absolute path.

What can we use to achieve it?

• We can retrieve the path to the WordPress root directory by using the ABSPATH constant.

• We can get the current file\'s directory path by using __DIR__.

• PHP\'s str_replace() to remove a string from another string.

With this, we can remove the ABSPATH from __DIR__, obtaining a relative path to the current file\'s directory from the WordPress root, so that it works when it gets appended to the site url.

Code example

Let\'s suppose that we have the following files structure:

-> /inc
   -> current-file.php
   -> /assets
      -> your-file.js
      -> your-file.css

The following code would work:

// Get the path from the WordPress root to the current file\'s directory
$current_path = str_replace( ABSPATH, \'/\', __DIR__ );

// Relative path from the current file\'s directory to your asset.
$relative_path = \'/assets/your-file.js\'


// Enqueueing a script
wp_enqueue_script( \'your-handle\', $current_path . $relative_path );

// Enqueueing a stylesheet
wp_enqueue_style( \'your-handle\', $current_path . $relative_path );

Or we can write it shorter if we don\'t worry about readability (I don\'t in this case):

// Scripts
wp_enqueue_script( \'your-handle\', str_replace( ABSPATH, \'/\', __DIR__ ) . \'/assets/your-file.js\' );

// Stylesheets
wp_enqueue_style( \'your-handle\', str_replace( ABSPATH, \'/\', __DIR__ ) . \'/assets/your-file.css\' );

Notice that in the case that our asset was located in a directory above the file where we are enqueueing it, the relative path should be something like \'/../assets/your-file.js\'.

Here is another example:

-> /inc
   -> current-file.php
-> /assets
   -> your-file.js
   -> your-file.css

And then

// Scripts
wp_enqueue_script( \'your-handle\', str_replace( ABSPATH, \'/\', __DIR__ ) . \'/../assets/your-file.js\' );

// Stylesheets
wp_enqueue_style( \'your-handle\', str_replace( ABSPATH, \'/\', __DIR__ ) . \'/../assets/your-file.css\' );

I hope this helps if anyone else wonders how to enqueue a script without knowing the final path of the file beforehand.

使用过滤器style_loader_src. 此筛选器将传递完整的src（即。http://localhost:8080/wordpress/style.css?ver=4.9.4), 然后您可以根据需要修改以删除域。例如

function style_loader_src_make_relative ( $src, $handle ) {
  // Remove the domain part. 
  // site_url() = http://localhost:8080
  $src = str_replace(site_url(), "", $src); 
  
  return $src;  
}
add_filter(\'style_loader_src\', \'style_loader_src_make_relative\', 10, 2 );