Description
Preconditions (*)
- Latest Magento 2.3.4 (Developer Mode)
- A category containing many (simple) products (in this case about 2600)
- No Varnish
- Apache + PHP7.3-FPM (happens with 7.2 too)
Steps to reproduce (*)
It seems magento creates http headers that are too long for most or some apache configurations. For me it happens when visiting a category page with many products.
PHP error log:
[Fri Feb 21 09:20:55.678915 2020] [proxy_fcgi:error] [pid 13470:tid 140320488904448] [client XXXXX:53641] Premature end of script headers: index.php, referer: https://XXXXX/shop/catalog/category/view/id/3
[Fri Feb 21 09:20:55.678978 2020] [proxy_fcgi:error] [pid 13470:tid 140320488904448] [client XXXXX:53641] AH01070: Error parsing script headers, referer: https://XXXXX/shop/catalog/category/view/id/3
[Fri Feb 21 09:20:55.678984 2020] [proxy_fcgi:error] [pid 13470:tid 140320488904448] (22)Invalid argument: [client XXXXX:53641] AH01075: Error dispatching request to : , referer: https://XXXXX...
Expected result (*)
I can understand that these headers are important for caching, and the HTTP spec doesnt define a limit for header sizes.
But most servers do in fact implement a limit (around ~8k), so i think this is a bug that should be fixed. https://stackoverflow.com/questions/686217/maximum-on-http-header-values
Actual result (*)
In my specific case, the http response is cached by magento FPC, and returned to the client in:
magento/vendor/magento/framework/App/Http.php:122
The X-Magento-Tags heade size is 27kB. The content is made up of strings like this one: cat_p_2611,cat_p,cat_p_2584,cat_p_2585.
If i add the following in the row after, the page works again:
$this->_response->setHeader('X-Magento-Tags', "test");