W3TC and Google XML Sitemaps – XML declaration error

The code for displaying and generating “googlenewsfeed” on the page “Google News Feed” with selected “Page template” here:
https://pastebin.com/7ahHDmLN

The code for google-news-sitemap.xsl is here:
https://pastebin.com/urm7qFUN

That new “Google News RSS Feed” for Google News Publisher is called from functions.php with:

// register new Google News Feed RSS - because of the error of needed "full" description for post and content in body for guidelines
add_action('init', 'customRSS');
function customRSS(){
    add_feed('googlenewsfeed', 'customRSSFunc');
}
function customRSSFunc(){
    get_template_part('rss', 'googlenewsfeed');
}

The code for “rss.php” file which is displaying and generating “goolenewsfeed” RSS Feed here:
https://pastebin.com/8nm2MWLw

Maybe I have to change the code, or add the “page” or that “feed” under the “do not cache” somewhere?

Why that occurs on PHP 7.4 is more questioning, because it was working fine on PHP 7.2 until 5 days and it is still working on other Website running for 2-3 months on PHP 7.3.

The setup of the W3TC configuration (cache, redis, page cache, php, opcache, nginx …) and general Linux and LEMP web server is exactly the same.

• This reply was modified 4 years ago by Fritex. Reason: rss.php file

Also, under “pgcache__purge__feed__types” there are checked:
– rdf, rss, rss2, atom, googlenewsfeed (and the new RSS feed registered inside functions.php)

Can I try it, wow can I exclude URL https://www.racunalo.com/google-news-sitemap/ from Page Cache and/or somewhere else?

Because under “page_enhanced” folder i have “googlenewsfeed” – so it caches it regarding the value “googlenewsfeed/” added under the field “browsercache_no404wp_exceptions” and field “pgcache_reject_uri” and also checked to purge feed “googlenewsfeed” under the field “pgcache__purge__feed__types”?

Because, still “1st line empty” when “not logged-in”:
view-source:https://www.racunalo.com/googlenewsfeed/

Whil being “logged in” the 1st line starts fine with <?xml> and it’s not empty.

Either, that is again, new registered feed in functions.php, not a “page” …

Or maybe my code is bad for the new feed “google-news-sitemap/”.

Or maybe not the code itself, maybe in functions.php of the theme I am calling something somewhere, some file, which has “the white space”, and after calling the .php file I am actually calling to register the new rss feed “google-news-sitemap”?

Not sure about it …

• This reply was modified 4 years ago by Fritex. Reason: explanation
• This reply was modified 4 years ago by Fritex.
• This reply was modified 4 years ago by Fritex.
• This reply was modified 4 years ago by Fritex. Reason: empty 1st line for public page cache, but not so when logged-in <1st line starts with ?xml

Also, have to mention, behind the CloudFlare Pro package …

So, when not logged-in and considering all options above:
– https://imgur.com/a/eSjPCuc

When logged-in WordPress:
– https://imgur.com/a/zDGeDTa

Difference:
Error because “empty start line” and cached version for all visitors/bots/Google when no logged-in WordPress?
VS
No error when logged-in WordPress as user/admin?

Also, index.php of the WordPress has already got the code:

function ___wejns_wp_whitespace_fix($input) {
    $allowed = false;
    $found = false;
    foreach (headers_list() as $header) {
        if (preg_match("/^content-type:\\s+(text\\/|application\\/((xhtml|atom|rss)\\+xml|xml))/i", $header)) {
            $allowed = true;
        }
        if (preg_match("/^content-type:\\s+/i", $header)) {
            $found = true;
        }
    }
    if ($allowed || !$found) {
        return preg_replace("/\\A\\s*/m", "", $input);
    } else {
        return $input;
    }
}

Or maybe I should change something here in rss.php file:
– https://pastebin.com/8nm2MWLw

The extracted code from above link:

<?php
/**
* Template Name: Google News Feed RSS
*/
//$postCount = 50;
//$posts = query_posts('category__not_in=1,46&showposts=' . $postCount);
$args_gnr = array(
'post_type' => 'post',
'post_status' => 'publish',
'category__not_in' => array(1),
'showposts' => 50,
'orderby' => 'date',
'order' => 'DESC',
'post_status' => 'publish',
'post_type'=>'post'
);
$query_gnr = new WP_Query( $args_gnr );
header('Content-Type: '.feed_content_type('rss-http').'; charset='.get_option('blog_charset'), true);
echo '<?xml version="1.0" encoding="UTF-8"?>';
?>

Moved the above code few lines below …
And added:

define('DONOTCACHEPAGE', true);
define('DONOTCACHEDB', true);
define('DONOTCACHCEOBJECT', true);

So, the final code modification for rss.php for my custom generated “googlenewsfeed” looks like:

<?php
/**
* Template Name: Google News Feed RSS
*/
define('DONOTCACHEPAGE', true);
define('DONOTCACHEDB', true);
define('DONOTCACHCEOBJECT', true);
header('Content-Type: '.feed_content_type('rss-http').'; charset='.get_option('blog_charset'), true);
echo '<?xml version="1.0" encoding="UTF-8"?>';
?>
<rss version="2.0"
xmlns:content="https://purl.org/rss/1.0/modules/content/"
xmlns:media="https://search.yahoo.com/mrss/"
xmlns:wfw="https://wellformedweb.org/CommentAPI/"
xmlns:dc="https://purl.org/dc/elements/1.1/"
xmlns:atom="https://www.w3.org/2005/Atom"
xmlns:sy="https://purl.org/rss/1.0/modules/syndication/"
xmlns:slash="https://purl.org/rss/1.0/modules/slash/"
<?php do_action('rss2_ns'); ?>>
...
...
<?php
$args_gnr = array(
'post_type' => 'post',
'post_status' => 'publish',
'category__not_in' => array(1),
'showposts' => 50,
'orderby' => 'date',
'order' => 'DESC',
'post_status' => 'publish',
'post_type'=>'post'
);
$query_gnr = new WP_Query( $args_gnr );
if($query_gnr->have_posts()): while($query_gnr->have_posts()): $query_gnr->the_post(); ?>
<item>
<title><?php the_title_rss(); ?></title>
...
...
<?php rss_enclosure(); ?>
<?php do_action('rss2_item'); ?>
</item>
<?php endwhile; endif; wp_reset_postdata(); ?>
</channel>
</rss>

• This reply was modified 4 years ago by Fritex. Reason: Working after disabled page cache with define() php

And after that modification, it works perfectly and valid:
– https://imgur.com/a/t5X4kvg

But, as saying, the Google XML Sitemaps default sitemap.xml plugin had also had the same problem.
Then, changed the stated values on the fields few replies above, the error dissapeared.

Kind of a strange situation … some bug or due to the hm …

Nevermind, maybe someone finds it helpful to disable page cache and/or browser cache for sitemap.xml when using that plugin with W3TC.

Either, do not know if the RSS is valid but still the default WordPress one has “empty 1st line”:
– https://www.racunalo.com/feed/

So, supossing I have to somehow, modify the rss.php of the default WordPress?
Or how to exclude sitemaps completly from Page, Database, Object and browser cache?

• This reply was modified 4 years ago by Fritex.

Okay, added “feed/” (without quotes) under the stated fields to exclude the “feed/” from caching …

Maybe, the /feed/ is not “registered” as sitemap.xml URL, so the W3TC does not know?

Also, https://www.racunalo.com/feed/ – on FireFox it gives me the option to download it as a file because the conte-type HTTP header returned is “application/rss+xml; charset=UTF-8”.

Hello @fritex

First of all thank you for all the details provided and I am happy to assist you with this.
I hope I got it all so please let me know if I missed something.
When the option “Cache feeds: site, categories, tags, comments” is enabled in Performance>Page Cache>General, it means that feeds and in some cases sitemaps are cached. You are not seeing the issue when logged in because most probably the option “Don’t cache pages for logged in users is enabled”
This being said, when you excluded the feed and the sitemap from being cached the issue went away.
As for the application/rss+xml; charset=UTF-8, try enabling the option “Handle XML mime type” in Performance>Page Cache (the last option at the bottom of the page) which should return the correct Content-Type header for XML files (e.g., feeds and sitemaps).
I hope this helps!
THanks!

Got it, thanks!