Assets.php causes headers already sent error
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I think I found an issue that needs attention.
I see ongoing entries that are stacking up in the PHP error log:
[22-May-2025 19:19:43 UTC] PHP Warning: Cannot modify header information – headers already sent by (output started at /home/xxxxxxxxxx/public_html/wp-content/plugins/wp-table-builder/v2/inc/Utils/Assets.php:79) in /home/xxxxxxxxxx/public_html/wp-admin/admin-header.php on line 14
WP Table Builder seems to accidentally send output (text, spaces, or something else) too early. This confuses PHP and causes that warning. It’s kind of like trying to seal a letter after it’s already dropped it in the mailbox — it’s too late!
I was able to fix the issue and test that everything’s working, by doing the following below.
Open file: /wp-content/plugins/wp-table-builder/v2/inc/Utils/Assets.php
Caveat: Make a backup of this file first! 😉Find this:
echo AssetLoader::get_scripts();and replace with this:
add_action('admin_footer', function () {
echo AssetLoader::get_scripts();
});Also, find this:
echo '<script type="text/javascript">var WPTB_CFG = ' . json_encode($data) . ';</script>';and replace with this:
add_action('admin_footer', function () use ($data) {
echo '<script type="text/javascript">var WPTB_CFG = ' . json_encode($data) . ';</script>';
});Then test that things are working.
In my case this fixed the issue, log does not get filled with repeated entries and WP Table Builder continues to work great.
I hope this helps others out.
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Thanks Saad @protibimbok
Sorry, still getting the issue.
[26-May-2025 15:49:28 UTC] PHP Warning: Cannot modify header information - headers already sent by (output started at /home/xxxxxxxxxx/public_html/wp-content/plugins/wp-table-builder/v2/inc/Utils/Assets.php:82) in /home/xxxxxxxxxx/public_html/wp-admin/admin-header.php on line 14This only happens when in the backend, duplicating tables and then editing them. I see no such log entries when surfing front-end pages containing tables.
Based on the log entry, it suggests a redirect or setting cookies occured, but it was too late, output had already been sent to the browser. It could be a space, newline, or echo that’s the cause? – Since PHP sends HTTP headers before any actual content (like HTML or echo output).
Update…
At line 82 of /wp-content/plugins/wp-table-builder/v2/inc/Utils/Assets.php, we see this:
echo '<script type="text/javascript">var WPTB_CFG = ' . json_encode($data) . ';</script>';The echo sends output to the browser. Once that happens, PHP can no longer send HTTP headers, which are needed for things like redirects, setting cookies, or any call to header().
So later, when admin-header.php (called by WordPress core) tries to send headers, which it always does – PHP throws a warning because it’s too late.
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