Page caching is not detected (wp-rocket)

[KinG-InFeT]

Bug Description

detect cache plugin not work correctly, please see this ticket:
wp-media/wp-rocket#4638

Expected Behaviour

detect cache plugin correctly

Screenshots

No response

PHP Version

7.4.21 (fpm)

Plugin Version

2.2

AMP plugin template mode

Transitional

WordPress Version

5.8.3

Site Health

`

wp-core

version: 5.8.3
site_language: it_IT
user_language: it_IT
timezone: Europe/Rome
permalink: /%postname%/
https_status: true
multisite: false
user_registration: 1
blog_public: 1
default_comment_status: open
environment_type: production
user_count: 461
dotorg_communication: true

wp-paths-sizes

wordpress_path: /var/www/programmiedovetrovarli
wordpress_size: loading...
uploads_path: /var/www/programmiedovetrovarli/wp-content/uploads
uploads_size: loading...
themes_path: /var/www/programmiedovetrovarli/wp-content/themes
themes_size: loading...
plugins_path: /var/www/programmiedovetrovarli/wp-content/plugins
plugins_size: loading...
database_size: loading...
total_size: loading...

wp-dropins (2)

advanced-cache.php: true
object-cache.php: true

wp-active-theme

name: Neve Child (neve-child-master)
version: 1.0.0
author: ThemeIsle
author_website: https://themeisle.com
parent_theme: Neve (neve)
theme_features: core-block-patterns, hfg_support, widgets-block-editor, title-tag, post-thumbnails, automatic-feed-links, custom-logo, html5, customize-selective-refresh-widgets, custom-background, align-wide, editor-color-palette, fl-theme-builder-headers, fl-theme-builder-footers, fl-theme-builder-parts, header-footer-elementor, lifterlms-sidebars, lifterlms, service_worker, starter-content, amp, menus, widgets
theme_path: /var/www/programmiedovetrovarli/wp-content/themes/neve-child-master
auto_update: Disabilitato

wp-parent-theme

name: Neve (neve)
version: 3.1.3
author: ThemeIsle
author_website: https://themeisle.com
theme_path: /var/www/programmiedovetrovarli/wp-content/themes/neve
auto_update: Disabilitato

wp-themes-inactive (1)

Twenty Twenty-One: version: 1.4, author: the WordPress team, Aggiornamenti automatici abilitati

wp-plugins-active (23)

Ad Inserter Pro: version: 2.7.8, author: Ad Inserter Pro, Aggiornamenti automatici disabilitati
Akismet Anti-Spam: version: 4.2.1, author: Automattic, Aggiornamenti automatici disabilitati
AMP: version: 2.2.0, author: AMP Project Contributors, Aggiornamenti automatici disabilitati
Autoptimize: version: 2.9.5, author: Frank Goossens (futtta), Aggiornamenti automatici disabilitati
GDPR Cookie Consent: version: 2.0.7, author: WebToffee, Aggiornamenti automatici disabilitati
Google Adsense Pages Violation Check: version: 1.0.0, author: Vincenzo Luongo, Aggiornamenti automatici disabilitati
Ko-fi Button: version: 1.0.3, author: Ko-fi Team; www.ko-fi.com, Aggiornamenti automatici disabilitati
Manage Notification E-mails: version: 1.8.2, author: Virgial Berveling, Aggiornamenti automatici disabilitati
Newsletter, SMTP, Email marketing and Subscribe forms by Sendinblue: version: 3.1.30, author: Sendinblue, Aggiornamenti automatici disabilitati
Ninja Forms: version: 3.6.7, author: Saturday Drive, Aggiornamenti automatici disabilitati
Redirection: version: 5.1.3, author: John Godley, Aggiornamenti automatici disabilitati
Redis Object Cache: version: 2.0.22, author: Till Krüss, Aggiornamenti automatici disabilitati
Site Kit by Google: version: 1.48.1, author: Google, Aggiornamenti automatici disabilitati
Super Progressive Web Apps: version: 2.2, author: SuperPWA, Aggiornamenti automatici disabilitati
UpdraftPlus - Backup/Restore: version: 1.16.69, author: UpdraftPlus.Com, DavidAnderson, Aggiornamenti automatici disabilitati
WebP Express: version: 0.25.0, author: Bjørn Rosell, Aggiornamenti automatici disabilitati
WP Adsterra Dashboard: version: 1.2.2, author: Vincenzo Luongo, Aggiornamenti automatici disabilitati
wpDiscuz: version: 7.3.9, author: gVectors Team, Aggiornamenti automatici disabilitati
WP Rocket: version: 3.10.6, author: WP Media, Aggiornamenti automatici disabilitati
WP ShrtFly Integration: version: 1.0.0, author: Vincenzo Luongo, Aggiornamenti automatici disabilitati
WP Telegram: version: 3.1.7, author: WP Socio, Aggiornamenti automatici disabilitati
Yoast Duplicate Post: version: 4.3, author: Enrico Battocchi & Team Yoast, Aggiornamenti automatici disabilitati
Yoast SEO: version: 17.9, author: Team Yoast, Aggiornamenti automatici disabilitati

wp-media

image_editor: WP_Image_Editor_Imagick
imagick_module_version: 1687
imagemagick_version: ImageMagick 6.9.7-4 Q16 x86_64 20170114 http://www.imagemagick.org
imagick_version: 3.4.4
file_uploads: File uploads is turned off
post_max_size: 512M
upload_max_filesize: 512M
max_effective_size: 512 MB
max_file_uploads: 200
imagick_limits:
imagick::RESOURCETYPE_AREA: 122 MB
imagick::RESOURCETYPE_DISK: 1073741824
imagick::RESOURCETYPE_FILE: 768
imagick::RESOURCETYPE_MAP: 512 MB
imagick::RESOURCETYPE_MEMORY: 256 MB
imagick::RESOURCETYPE_THREAD: 1
imagemagick_file_formats: 3FR, AAI, AI, ART, ARW, AVI, AVS, BGR, BGRA, BGRO, BIE, BMP, BMP2, BMP3, BRF, CAL, CALS, CANVAS, CAPTION, CIN, CIP, CLIP, CMYK, CMYKA, CR2, CRW, CUR, CUT, DATA, DCM, DCR, DCX, DDS, DFONT, DNG, DPX, DXT1, DXT5, EPDF, EPI, EPS, EPS2, EPS3, EPSF, EPSI, EPT, EPT2, EPT3, ERF, FAX, FILE, FITS, FRACTAL, FTP, FTS, G3, G4, GIF, GIF87, GRADIENT, GRAY, GROUP4, H, HALD, HDR, HISTOGRAM, HRZ, HTM, HTML, HTTP, HTTPS, ICB, ICO, ICON, IIQ, INFO, INLINE, IPL, ISOBRL, ISOBRL6, JBG, JBIG, JNG, JNX, JPE, JPEG, JPG, JPS, JSON, K25, KDC, LABEL, M2V, M4V, MAC, MAGICK, MAP, MASK, MAT, MATTE, MEF, MIFF, MKV, MNG, MONO, MOV, MP4, MPC, MPEG, MPG, MRW, MSL, MTV, MVG, NEF, NRW, NULL, ORF, OTB, OTF, PAL, PALM, PAM, PATTERN, PBM, PCD, PCDS, PCL, PCT, PCX, PDB, PDF, PDFA, PEF, PES, PFA, PFB, PFM, PGM, PICON, PICT, PIX, PJPEG, PLASMA, PNG, PNG00, PNG24, PNG32, PNG48, PNG64, PNG8, PNM, PPM, PREVIEW, PS, PS2, PS3, PSB, PSD, PTIF, PWP, RADIAL-GRADIENT, RAF, RAS, RAW, RGB, RGBA, RGBO, RGF, RLA, RLE, RMF, RW2, SCR, SCT, SFW, SGI, SHTML, SIX, SIXEL, SPARSE-COLOR, SR2, SRF, STEGANO, SUN, TEXT, TGA, THUMBNAIL, TIFF, TIFF64, TILE, TIM, TTC, TTF, TXT, UBRL, UBRL6, UIL, UYVY, VDA, VICAR, VID, VIFF, VIPS, VST, WBMP, WMV, WPG, X, X3F, XBM, XC, XCF, XPM, XPS, XV, XWD, YCbCr, YCbCrA, YUV
gd_version: 2.3.0
gd_formats: GIF, JPEG, PNG, WebP, BMP, XPM
ghostscript_version: not available

wp-server

server_architecture: Linux 5.4.0-92-generic x86_64
httpd_software: Apache/2.4.41 (Ubuntu)
php_version: 7.4.21 64bit
php_sapi: fpm-fcgi
max_input_variables: 10000
time_limit: 999
memory_limit: 2048M
max_input_time: -1
upload_max_filesize: 512M
php_post_max_size: 512M
curl_version: 7.68.0 OpenSSL/1.1.1f
suhosin: false
imagick_availability: true
pretty_permalinks: true
htaccess_extra_rules: true

wp-database

extension: mysqli
server_version: 8.0.27-0ubuntu0.20.04.1
client_version: mysqlnd 7.4.21

wp-constants

WP_HOME: undefined
WP_SITEURL: undefined
WP_CONTENT_DIR: /var/www/programmiedovetrovarli/wp-content
WP_PLUGIN_DIR: /var/www/programmiedovetrovarli/wp-content/plugins
WP_MEMORY_LIMIT: 40M
WP_MAX_MEMORY_LIMIT: 2048M
WP_DEBUG: false
WP_DEBUG_DISPLAY: false
WP_DEBUG_LOG: false
SCRIPT_DEBUG: false
WP_CACHE: true
CONCATENATE_SCRIPTS: undefined
COMPRESS_SCRIPTS: undefined
COMPRESS_CSS: undefined
WP_LOCAL_DEV: undefined
DB_CHARSET: utf8
DB_COLLATE: undefined

wp-filesystem

wordpress: writable
wp-content: writable
uploads: writable
plugins: writable
themes: writable
mu-plugins: writable

neve

api: Sì
child: /var/www/programmiedovetrovarli/wp-content/themes/neve-child-master/functions.php,

/var/www/programmiedovetrovarli/wp-content/themes/neve-child-master/images/stripe.png,

/var/www/programmiedovetrovarli/wp-content/themes/neve-child-master/images/dark_wall.jpg,

/var/www/programmiedovetrovarli/wp-content/themes/neve-child-master/images/crypto-logos/,

/var/www/programmiedovetrovarli/wp-content/themes/neve-child-master/screenshot.png,

/var/www/programmiedovetrovarli/wp-content/themes/neve-child-master/style.css
customizer_css:
body {
background: url("/wp-content/themes/neve-child-master/images/dark_wall.jpg");
box-shadow: 0 1px 3px rgba(0, 0, 0, .5), inset 0 1px 1px rgba(255, 255, 255, .2);

box-sizing: border-box;
outline: 0;
	-webkit-text-size-adjust: 100%;

}
.wp-block-search__input,
.ninja-forms-field,
.search-field {
color: black !important;
}

footer,
.single-page-container,
.single-post-container {
box-shadow: 0 1px 3px rgba(0, 0, 0, .5), inset 0 1px 1px rgba(255, 255, 255, .2);
box-sizing: border-box;
outline: 0;
-webkit-text-size-adjust: 100%;
}

.site-logo h1, .site-logo p {
font-size: 1.5em;
}

.wp-block-latest-posts.is-grid li ,
.nv-page-title-wrap.nv-big-title .nv-page-title h1{
text-align: center;
}

ul.cbd-classic-list li {
float:left;
}

.cbd-classic-list h2.CDBBC-title,
.cbd-classic-list .cdbbc_tag {
color: #222 !IMPORTANT;
}

.hfg_header .header-main-inner {

background-color: #1d1d1d;
-webkit-box-shadow: inset 0 2px 3px rgb(255 255 255 / 20%);
-moz-box-shadow: inset 0 2px 3px rgba(255, 255, 255, .2);
box-shadow: inset 0 2px 3px rgb(255 255 255 / 20%);
background-image: -webkit-linear-gradient(bottom, #1a1b1f, #212528);
background-image: -moz-linear-gradient(bottom, #1a1b1f, #212528);
background-image: -o-linear-gradient(bottom, #1a1b1f, #212528);
background-image: linear-gradient(to top, #1a1b1f, #212528);

}

.hfg_header .header-main-inner:before{
/z-index: -1;/
background: url("/wp-content/themes/neve-child-master/images/stripe.png") top left;
background-repeat: repeat;
border: 1px solid #000;
width: 100%;
height: 100%;
position: absolute;
top: 0;
left: 0;
display: block!important;
content: '';
}

.floatingchat-container-wrap {
bottom: 200px !important;
}

google-site-kit

version: 1.48.1
php_version: 7.4.21
wp_version: 5.8.3
reference_url: https://www.programmiedovetrovarli.it
amp_mode: secondary
site_status: connected-site
user_status: authenticated
verification_status: verified-non-site-kit
connected_user_count: 1
active_modules: site-verification, search-console, adsense, analytics, analytics-4, pagespeed-insights
required_scopes:
openid: ✅
https://www.googleapis.com/auth/userinfo.profile: ✅
https://www.googleapis.com/auth/userinfo.email: ✅
https://www.googleapis.com/auth/siteverification: ✅
https://www.googleapis.com/auth/webmasters: ✅
https://www.googleapis.com/auth/adsense.readonly: ✅
https://www.googleapis.com/auth/analytics.readonly: ✅
capabilities:
googlesitekit_authenticate: ✅
googlesitekit_setup: ✅
googlesitekit_view_posts_insights: ✅
googlesitekit_view_dashboard: ✅
googlesitekit_view_module_details: ✅
googlesitekit_manage_options: ✅
enabled_features:
dashboardSharing: ⭕
ideaHubModule: ⭕
serviceSetupV2: ⭕
swgModule: ⭕
userInput: ⭕
unifiedDashboard: ⭕
search_console_property: https://www.programmiedovetrovarli.it/
adsense_account_id: pub-502•••••••••••••
adsense_client_id: ca-pub-502•••••••••••••
adsense_account_status: approved
adsense_use_snippet: yes
adsense_web_stories_adunit_id: none
analytics_account_id: 4069••••
analytics_property_id: UA-4069••••••
analytics_profile_id: 7210••••
analytics_use_snippet: yes
analytics_4_property_id: none
analytics_4_web_data_stream_id: none
analytics_4_measurement_id: none
analytics_4_use_snippet: yes

amp_wp

amp_slug_query_var: amp
amp_slug_defined_late: false
amp_mode_enabled: transitional
amp_reader_theme: legacy
amp_templates_enabled: post, page, is_singular, is_front_page, is_home, is_archive, is_author, is_date, is_search, is_404, is_category, is_tag
amp_serve_all_templates: true
amp_css_transient_caching_disabled: n/a
amp_css_transient_caching_threshold: 5000 transients per day
amp_css_transient_caching_sampling_range: 14 days
amp_css_transient_caching_transient_count: 783
amp_css_transient_caching_time_series:
20210928: 764
20210929: 780
20210930: 580
20211001: 723
20211002: 762
20211003: 772
20211004: 773
20211005: 777
20211006: 779
20211007: 697
20211008: 749
20211009: 772
20211010: 778
20211011: 783
amp_libxml_version: 2.9.12

`

Gutenberg Version

No response

OS(s) Affected

VPS Linux

Browser(s) Affected

All

Device(s) Affected

All

Acceptance Criteria

No response

Implementation Brief

No response

QA Testing Instructions

No response

Demo

No response

Changelog Entry

No response

[westonruter]

See conversation at wp-media/wp-rocket#4638 (comment).

We may want to add Last-Modified and ETag as signals for whether page caching is enabled. It's true that this is not 100% indicative of page caching being active, but it's also true that Expires/Cache-Control are not 100% indicative either.

Also, along with Age we may need to add some host-specific headers to sniff for page caching, including X-Cache, CF-Cache-Status, X-Kinsta-Cache, X-Cache-Enabled/X-Cache-Disabled, etc. We should re-check the various plugins in the directory to find any such custom headers, and then also look at popular hosts to see what they are sending back. Lastly, a full list of response headers could be obtained from HTTP Archive.

[westonruter]

Also consider checking if advanced-cache.php is present as an adequate signal.

[westonruter]

See wp-media/wp-rocket#4638 (comment):

The only sensible timing-based check seems to me to re-fetch the homepage 3 times, and if any of them response in less than 200ms then we can presume a page cache is responsible for such a “fast” response, or else the site is fast enough that page caching is not necessary. PageSpeed Insights recommends a TTFB under 200ms.

So I'd say we change the test so that instead of checking for page caching we instead check for the need for page caching. As part of that we:

1. Check for a <200ms response
2. Check for one of the recognized response headers for page caching.

The test results would then be as follows:

<200ms response	Page caching detected	Test Result
Yes	Yes	Good
Yes	No	Recommended
No	No	Critical

In the second case, this catches the case where your site responds just fine when it is getting little traffic. But if the site lacks page caching, it can quickly crash if no page caching is in place.

[westonruter]

Successful detection of page caching includes the following, where if any condition is true the rest are skipped:

1. The advanced-cache.php drop-in is present, enable_loading_advanced_cache_dropin filter returns true, and WP_CACHE is true. (New)
2. The Cache-Control response header is present and has a non-zero max-age. (Existing)
3. The Expires response header is present and has a future value. (Existing)
4. The Last-Modified or ETag response headers are present (New)
5. The Age response header header is present. (Existing)
6. One or more custom response headers are present: X-Cache, X-Proxy-Cache, X-Kinsta-Cache, CF-Cache-Status, CF-Apo-Via, etc. (New)

I suggest the existing \AmpProject\AmpWP\Admin\SiteHealth::check_for_page_caching() method be changed so that instead of returning a bool it returns an array that contains three:

1. advanced_cache_present (bool) — WP_CACHE && apply_filters( 'enable_loading_advanced_cache_dropin', true ) && file_exists( WP_CONTENT_DIR . '/advanced-cache.php' )
2. page_caching_response_headers (array) — a list of the headers that were detected to indicate page caching is enabled
3. response_timing (array) — list of the response times in milliseconds

These three data points can then be used to determine whether the test is in the Good, Recommended, or Critical state. It can also be used to show the user the results of the test (displaying the values returned by that method).

[westonruter]

For response_timing, the test is considered a pass if one of the values are less than 200ms.

[westonruter]

PageSpeed Insights recommends a TTFB under 200ms.

This seems out of date. The current audit mentions a target of 100ms: https://github.com/GoogleChrome/lighthouse/blob/82772f93645989c9c250c78a0ad10d55f3372beb/lighthouse-core/audits/server-response-time.js#L27-L30

The web.dev article mentions the audit failing if it takes more than 600ms to load the main document: https://web.dev/time-to-first-byte/

It's probably unreasonable for page caching plugins on shared hosts to get <200ms responses. So 600ms would probably be better, and since it aligns with PageSpeed Insights.

[westonruter]

In regards to the 3-iteration loop in check_for_page_caching, instead of short-circuiting when it finds the first page caching response header present, it should instead continue iterating (up to 3 times) until it gets a sub-600ms response. (Alternatively, it could always do 3 iterations and then the median response time could be used for the test results as opposed to the minimum.)

[westonruter]

@KinG-InFeT Would you be willing to test the improvement in the latest 2.2.x production build?

[KinG-InFeT]

@KinG-InFeT Would you be willing to test the improvement in the latest 2.2.x production build?

yes, now Site Health not return the error for cache 👍