############################################################################
#### настройки php ####
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php_value max_execution_time 500
php_value max_input_time 500
php_value upload_max_filesize 30M
php_value post_max_size 30M
Options -Indexes
AddCharset utf-8 .js
ErrorDocument 403 /error/404
ErrorDocument 404 /error/404
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#### Компрессия статического контента для гугл спид тест ####
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<IfModule mod_deflate.c>
AddType image/svg+xml .svg
AddOutputFilterByType DEFLATE image/svg+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/vnd.ms-fontobject
AddOutputFilterByType DEFLATE application/x-font
AddOutputFilterByType DEFLATE application/x-font-opentype
AddOutputFilterByType DEFLATE application/x-font-otf
AddOutputFilterByType DEFLATE application/x-font-truetype
AddOutputFilterByType DEFLATE application/x-font-ttf
AddOutputFilterByType DEFLATE application/x-javascript
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE font/opentype
AddOutputFilterByType DEFLATE font/otf
AddOutputFilterByType DEFLATE font/ttf
AddOutputFilterByType DEFLATE image/svg+xml
AddOutputFilterByType DEFLATE image/x-icon
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/javascript
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE image/svg+xml
</IfModule>
<IfModule mod_expires.c>
ExpiresActive on
ExpiresByType image/jpeg "access plus 1 year"
ExpiresByType image/svg "access plus 1 year"
ExpiresByType image/gif "access plus 1 year"
ExpiresByType image/png "access plus 1 year"
ExpiresByType text/javascript "access plus 1 year"
ExpiresByType text/css "access plus 1 year"
ExpiresByType application/javascript "access plus 1 year"
ExpiresByType application/vnd.ms-fontobject "access plus 1 year"
ExpiresByType application/x-font-ttf "access plus 1 year"
ExpiresByType application/x-font-opentype "access plus 1 year"
ExpiresByType application/x-font-woff "access plus 1 year"
ExpiresByType image/svg+xml "access plus 1 year"
</IfModule>
<IfModule mod_headers.c>
<filesmatch "\.(ico|flv|jpg|jpeg|webp|png|gif|css|swf|woff|pdf)$">
Header set Cache-Control "max-age=31536000, public"
</filesmatch>
<filesmatch "\.(html|htm)$">
Header set Cache-Control "max-age=7200, private, must-revalidate"
</filesmatch>
<filesmatch "\.(pdf)$">
Header set Cache-Control "max-age=86400, public"
</filesmatch>
<filesmatch "\.(js|otf|ttf|woff|woff2)$">
Header set Cache-Control "max-age=31536000, private"
</filesmatch>
</IfModule>
############################################################################
#### Редиректы и прочее ####
############################################################################
<IfModule mod_headers.c>
RequestHeader set X-Prerender-Token "КОД ТОКЕНА"
RequestHeader set X-Prerender-Version "prerender-apache@2.0.0"
</IfModule>
RewriteEngine On
RewriteCond %{HTTPS} off
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
RewriteCond %{HTTP_HOST} ^www.site.ru$ [NC]
RewriteRule ^(.*)$ httpы://site.ru/$1 [R=301,L]
<IfModule mod_proxy_http.c>
RewriteCond %{HTTP_USER_AGENT} googlebot|bingbot|yandex|baiduspider|facebookexternalhit|twitterbot|rogerbot|linkedinbot|embedly|quora\ link\ preview|showyoubot|outbrain|pinterest\/0\.|pinterestbot|slackbot|vkShare|W3C_Validator|whatsapp [NC,OR]
RewriteCond %{QUERY_STRING} _escaped_fragment_
RewriteCond %{REQUEST_URI} ^(?!.*?(\.js|\.css|\.xml|\.less|\.png|\.jpg|\.jpeg|\.gif|\.pdf|\.doc|\.txt|\.ico|\.rss|\.zip|\.mp3|\.rar|\.exe|\.wmv|\.doc|\.avi|\.ppt|\.mpg|\.mpeg|\.tif|\.wav|\.mov|\.psd|\.ai|\.xls|\.mp4|\.m4a|\.swf|\.dat|\.dmg|\.iso|\.flv|\.m4v|\.torrent|\.ttf|\.woff|\.svg))
RewriteRule ^(index\.html|index\.php)?(.*) https://service.prerender.io/https://site.ru/$2 [P,END]
</IfModule>
############################################################################
#### ЧПУ сайта ####
############################################################################
RewriteCond %{SCRIPT_FILENAME} !-f
RewriteCond %{SCRIPT_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !router.php$
RewriteRule ^(.*)$ router.php/$1
Однако я вижу у вас мод прокси, он очень редко используется, я бы не рекомендовал его использовать.
Вместо этого в 404.php впишите php proxy
это будет куда более ожидаемое действие а так же там можно делать str_replace и тд.
