WP script versioning breaks cross-site caching?

Question

I am loading JQuery from the google CDN using the following code:

wp_deregister_script('jquery'); 
 wp_register_script(
    'jquery', // handle - WP uses this name to refer to script
    'http://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js',
     array(), // Array of handles representing scripts that this one depends on.
     false, // Version number - defaults to false.
     false // false = put script in header, true = put in footer
 );
wp_enqueue_script('jquery');

In firebug I see that wordpress appends '?ver=3.0.4' to the URL to control caching. In fact there doesn't seem to be any way to stop WP from appending something to the URL - I can provide my own string in the call to wp_register_script() but WP will use the default 'ver=3.0.4' if i leave it blank (or "false")

I believe the appended version string stop the user's browser from re-using a cached copy of the file that it might have downloaded from a different website. E.g.

1. User visits www.example.com which loads ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js so it is now in browser cache.
2. User then visits my site which loads ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js?ver=3.0.4
3. The user's browser not use it's cached copy because the URLs are different.

Since cross-site caching is one of the main reasons I want to use Google's CDN, are there any solutions to this other than loading the script manually (not ideal) or hacking WP core?

TIA

/Eoin/

Answer 1

Use null as $ver param:

wp_deregister_script( 'jquery' );
wp_register_script( 'jquery', 'https://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js', false, null);
wp_enqueue_script('jquery');

Output:

<script type='text/javascript' src='https://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js'></script>

Answer 2

I remove version like this, can be easily written out to match multiple domains:

add_filter( 'script_loader_src', 'jquery_unversion' );

function jquery_unversion( $src ) {

    if( strpos( $src, 'ajax.googleapis.com' ) )
        $src = remove_query_arg( 'ver', $src );

    return $src;
}

Answer 3

Short answer: No.

I looked at the code in wp-includes/scriptloader.php and there is nothing that indicates an "option" about supplying the version number.

You can, however, simply put this in your footer (or header) as an explicit <script> tag. Of course, this completely defeats the whole idea of wp_register_script(), but that's true with a number of "features" in WP. (Don't get me started on the brain-dead/broken parsing of shortcodes with regexps.)

Answer 4

Use this in your theme's functions.php

function remove_wp_script_version( $src ){

    global $wp_version;

  $version_str = '?ver='.$wp_version;
  $version_str_offset = strlen( $src ) - strlen( $version_str );

  if( substr( $src, $version_str_offset ) == $version_str )
    return substr( $src, 0, $version_str_offset );
  else
    return $src;
}
add_filter( 'script_loader_src', 'remove_wp_script_version', 15, 1 ); 

If you want, you can also add another filter to remove versioning from stylesheets.

add_filter( 'style_loader_src', 'remove_script_version', 15, 1 );

I don't understand why they put this in the core. Not only does it mess with caching of external scripts but it also gives out unnecessary information about the site. I just use the filters above and add my own version numbers to custom scripts as needed.

Answer 5

Including jQuery from Google's CDN also requires some extra code to handle the noConflict mode issue.

I suggest that instead of rolling your own, use a plugin designed to handle it properly. This one works great: http://wordpress.org/extend/plugins/use-google-libraries/

Simple no-hassle setup. Just activate it and it will replace all relevant libraries with Google's CDN versions.

Answer 6

Thank you all for your responses. In the end this is the code I used (posting here for the sake of future searchers):

function control_wp_url_versioning($src)
{
    // $src is the URL that WP has generated for the script or stlye you added 
    // with wp_enqueue_script() or wp_enqueue_style(). This function currently 
    // removes the version string off *all* scripts. If you need to do something 
    // different, then you should do it here.
    $src = remove_query_arg( 'ver', $src );
    return $src;
}

// The default script priority is 10. We load these filters with priority 15 to 
// ensure they are run *after* all the default filters have run. 
add_filter('script_loader_src', 'control_wp_url_versioning', 15); 
add_filter('style_loader_src', 'control_wp_url_versioning', 15);