I'm working on a WordPress plugin, and I have a checkbox option to add cache control headers. I'd like to write to the htaccess file if the option is set to 1, else remove the new content.

I've been trying to achieve this using insert_with_markers() but to no avail. These are the functions I've been using:

function write_cache_control(){
    $htaccess = get_home_path().".htaccess";
    $lines = array();
    $lines[] = '<FilesMatch "\.(js|css|jpg|jpeg|gif|png|pdf|swf|svg|svgz|ico|ttf|ttc|otf|eot|woff|woff2|webp)$">';
    $lines[] = '<IfModule mod_headers.c>';
    $lines[] = 'ExpiresActive On';
    $lines[] = 'ExpiresDefault  "access plus 1 month"';
    $lines[] = 'Header set Cache-Control "public, immutable, max-age=2628000, s-maxage=2628000"';
    $lines[] = 'Header set Access-Control-Allow-Origin "*';
    $lines[] = '</IfModule>';
    $lines[] = '</FilesMatch>';
    insert_with_markers($htaccess, "Cache Control", $lines);
}

function clear_cache_control(){
    $htaccess = get_home_path().".htaccess";
    insert_with_markers($htaccess, "Cache Control", '');
}

I've tried hooking them into wp, init & wp_init but nothing seems to work. Is there something I'm missing? Should I be using WordPress' wp_rewrite or PHP's fread & fwrite or something along those lines?

I'm working on a WordPress plugin, and I have a checkbox option to add cache control headers. I'd like to write to the htaccess file if the option is set to 1, else remove the new content.

I've been trying to achieve this using insert_with_markers() but to no avail. These are the functions I've been using:

function write_cache_control(){
    $htaccess = get_home_path().".htaccess";
    $lines = array();
    $lines[] = '<FilesMatch "\.(js|css|jpg|jpeg|gif|png|pdf|swf|svg|svgz|ico|ttf|ttc|otf|eot|woff|woff2|webp)$">';
    $lines[] = '<IfModule mod_headers.c>';
    $lines[] = 'ExpiresActive On';
    $lines[] = 'ExpiresDefault  "access plus 1 month"';
    $lines[] = 'Header set Cache-Control "public, immutable, max-age=2628000, s-maxage=2628000"';
    $lines[] = 'Header set Access-Control-Allow-Origin "*';
    $lines[] = '</IfModule>';
    $lines[] = '</FilesMatch>';
    insert_with_markers($htaccess, "Cache Control", $lines);
}

function clear_cache_control(){
    $htaccess = get_home_path().".htaccess";
    insert_with_markers($htaccess, "Cache Control", '');
}

I've tried hooking them into wp, init & wp_init but nothing seems to work. Is there something I'm missing? Should I be using WordPress' wp_rewrite or PHP's fread & fwrite or something along those lines?

• plugins
• php
• plugin-development
• htaccess
• cache

1 Answer 1

Almost all of your code is correct. I didn't even know about the insert_with_markers function, and now I do, so thank you.

In return, I believe I have your solution.

get_home_path() is not defined when any of the hooks (init,wp, etc.) you mentioned are triggered. That function is defined in the admin-side "file.php", which as part of the admin dashboard side of things, has not yet loaded.

The hook admin_init, however, should serve you well, presuming you are making those .htaccess changes on the admin side. If not, you could either include wp-admin/includes/file.php manually, or use an alternate way of finding .htaccess, such as the constant ABSPATH (although they are not equivalent).

Using the admin_init hook on the first function you provided, I found the rules written to my .htaccess file the next time I loaded a page on the admin side.

By the way, you might want to do a check for current_user_can( 'edit_files' ) before allowing that code to run.