The code below used to be Ok. But now I found that browsers do not cache .php files. Why? MY site is on share host. The host never reply. All the other extention files such as html, js, css, png, are fine cached, besides .php.
Header unset Pragma
FileETag None
Header unset ETag
# 1 YEAR
<filesMatch ".(ico|pdf|flv|jpg|jpeg|png|gif|swf|mp3|mp4)$">
Header set Cache-Control "public"
Header set Expires "Thu, 15 Apr 2015 20:00:00 GMT"
Header unset Last-Modified
</filesMatch>
# 2 HOURS
<filesMatch ".(html|htm|xml|txt|xsl|php)$">
Header set Cache-Control "max-age=7200, public"
</filesMatch>
<filesMatch ".(js|css)$">
Header set Cache-Control "public"
Header set Expires "Thu, 15 Apr 2014 20:00:00 GMT"
Header unset Last-Modified
</filesMatch>
Because PHP files can generate different output each time they run, servers don't send cache commands for the output: it might be different next time.
You can force caching by including Cache-control headers in the output generated by PHP, or by specifying the ContentType header from your PHP script.
Which of these is a better approach depends on what your script is doing. Either way, you can implement fine control over caching if your aplication requires it.
Related
############################
# FILES - CACHING: CONTROL #
############################
Header set Cache-Control "max-age=2592000, public"
<FilesMatch "\.(?:bmp|css|cur|gif|ico|jp(?:eg?|g)|js|png|svgz?|tiff?|webp)$">
Header set Cache-Control "max-age=31536000, public"
</FilesMatch>
<FilesMatch "\.(?:html?|json|php|xml)$">
Header set Cache-Control "max-age=0, must-revalidate, no-cache, no-store, post-check=0, pre-check=0, private"
</FilesMatch>
<FilesMatch "\.(?:atom|rdf|rss)$">
Header set Cache-Control "max-age=3600, public"
</FilesMatch>
Header merge Cache-Control "no-transform"
This is a snippet of my htacces in which I handle the Cache-Control header. By default, for all the files, it is set to max-age=2592000, public.
On the bottom I'm always trying to append a no-transform directive but it simply doesn't work. It... well it just does nothing. The no-transform directive is never been set. I tried replacing merge with append, nothing changes.
Now, this is what I noticed. If I replace the third FilesMatch directive with:
<FilesMatch "\.(?:atom|rdf|rss)$">
Header set Cache-Control "max-age=3600, public"
Header merge Cache-Control "no-transform"
</FilesMatch>
It works. Every feed file of my site will have the no-transform directive. If I change the last line of my first snippet to:
<FilesMatch "^.+$">
Header merge Cache-Control "no-transform"
</FilesMatch>
Well... it works for all the files. Just... WHY?!
I also noticed another very strange behavior concerning headers. Let's say I want to force a keep-alive on connections. I insert this somewhere inside my htaccess file:
Header merge Connection "Keep-Alive"
And this is what I get in my response header:
Connection: Keep-Alive, Keep-Alive
Again... WHY?!
I suspect (though can't find any documentation to back this up as it's not 100% clear from this page: https://httpd.apache.org/docs/2.4/sections.html), that FilesMatch directives are processed after directives which are not in FileMatch.
Therefore even though you write this:
Header set Cache-Control "max-age=2592000, public"
<FilesMatch "\.(?:atom|rdf|rss)$">
Header set Cache-Control "max-age=3600, public"
</FilesMatch>
Header merge Cache-Control "no-transform"
Apache processes it like this:
Header set Cache-Control "max-age=2592000, public"
Header merge Cache-Control "no-transform"
<FilesMatch "\.(?:atom|rdf|rss)$">
Header set Cache-Control "max-age=3600, public"
</FilesMatch>
Which means the "later" set overrides the earlier merge. If you change the "set" in your FilesMatch pieces to "merge" you should see it work as it will no longer override it.
Though to be honest I think this way of writing you config is very difficult to follow. Since you are setting you cache control header four times why not just set the no-transform at the same time in each of the four set directives? Yes it's a tiny bit of repetition but a lot clearer and means you won't run into these order problems!
Your second issue is easier to explain from the documentation: http://httpd.apache.org/docs/current/mod/mod_headers.html#header:
merge ... Values in double quotes are considered different from otherwise identical unquoted values
So if value is Keep-Alive and you add "Keep-Alive" then you end up with "Keep-Alive Keep-Alive".
Btw as an aside you should not try to enable Keep-Alives just by setting the header. While that will work for the client, Apache needs to also keep the connection alive for the client to connect to, which it won't just by setting this header. So the client will think the connection is being kept alive but in fact it won't be as the server will close the connection anyway. You need to set it with the config like the following (which will also set the necessary headers for you):
KeepAlive On
MaxKeepAliveRequests 100
KeepAliveTimeout 5
I have a page on a site which uses random() twig, in Firefox and Chrome it is prevented from working because it gets cached as soon as the page loads.
Is there a way to turn off caching of a particular file via the Apache configs, lets call it default.html or even better just turn off caching for the script part of that file but keep caching image files?
I have tried .htaccess but this does not work.
The only way currently that allows the script to work is to turn off caching globally via PHP headers:
<?php
header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
header('Cache-Control: no-store, no-cache, must-revalidate');
header('Cache-Control: post-check=0, pre-check=0', FALSE);
header('Pragma: no-cache');
?>
But as I only need to turn off caching for an individual page, turning it off for everything seems crazy.
Figured it out, to target a specific file (in this case index.php), add this code to the bottom of .htaccess
<Files index.php>
FileETag None
Header unset ETag
Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate"
Header set Pragma "no-cache"
Header set Expires "Wed, 11 Jan 1984 05:00:00 GMT"
</Files>
Alternatively to target a specific selection of files, ie. I'd like to cache images but nothing else (files that match html, htm, js, css, php will not be cached):
<filesMatch "\.(html|htm|js|css|php)$">
FileETag None
Header unset ETag
Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate"
Header set Pragma "no-cache"
Header set Expires "Wed, 11 Jan 1984 05:00:00 GMT"
</filesMatch>
To check the .htaccess was being read I entered a few lines of rubbish at the bottom, found out it wasn't being read, renamed it from htaccess to .htaccess and it worked.
I have a .htaccess file that handles the browser caching. I set the rules with file extensions. How can I modify the following snippet to exclude a specific directory from the browser caching?
<FilesMatch "\.(gif|png|jpg|js|css|ico|woff|eot|svg|ttf)$">
Header set Cache-Control "max-age=2592000, public, must-revalidate"
Header unset Last-Modified
</FilesMatch>
I there any way to totally forbid the caching in this directory?
You can try to overwrite parent cache function. Just replace another htaccess file under desired folder and set to cache for 1 sec. Worked for me.
ExpiresActive On
ExpiresDefault A1
Header append Cache-Control must-revalidate
I want to set cache-headers using the mod_expires module from apache. My configuration looks somewhat like this:
<LocationMatch ^/static >
ExpiresDefault "access plus 1 years"
</LocationMatch>
The problem is, that the files are generated by a third system I don't control. These system provides files with the following headers:
Date Mon, 24 Oct 2011 08:39:02 GMT
Cache-Control no-cache,no-store,must-revalidate
Pragma no-cache
Expires Thu, 01 Dec 1994 16:00:00 GMT
These headers makes it impossible to set the cache-headers with mod_expires. http://httpd.apache.org/docs/2.2/mod/mod_expires.html tells us why:
When the Expires header is already part of the response generated by the server, for example when generated by a CGI script or proxied from an origin server, this module does not change or add an Expires or Cache-Control header.
Is there any possible way to circumvent this rule and overwrite the headers with mod_expires?
Update:
One possible solution, to avoid this limitation is to use only mod_headers to set the cache-headers. Unfortunately, this isn't an alternative because the values have to be calculated.
Thanks it advance.
Unfortunately, it's a known limitation and we had to fall back to use only mod_headers.
Regilero's suggestion won't work because header directives will be processed very late in the response processing - after mod_expire directive. So you'd unset the headers after mod_expires did (or didn't) what it was supposed to do.
If it's apache 2.2 you could try putting early at the end of each header directive. That will tell it to do this in an early stage of response processing as opposed to at the end.
so try:
<LocationMatch ^/static >
Header unset Cache-Control early
Header unset Pragma early
Header unset Expires early
ExpiresDefault "access plus 1 years"
</LocationMatch>
Haven't tested tho, but give it a try...
Have you tried mixing it with mod_headers?
<LocationMatch ^/static >
Header unset Cache-Control
Header unset Pragma
Header unset Expires
ExpiresDefault "access plus 1 years"
</LocationMatch>
Not tested, but in case of...
Despite various measure ments to setup correct caching code in htaccess file, I still get this error:
Specify a cache validator:
All static resources should have either a Last-Modified or ETag header. This will allow browsers to take advantage of the full benefits of caching.
Is there anything wrong with my htaccess caching settings? If you have improvements for these settings i will be very happy to hear. Thank you very much for your suggestions.
<IfModule mod_headers.c>
Header unset Pragma
FileETag None
Header unset ETag
ExpiresActive On
##### DYNAMIC PAGES
<FilesMatch "\\.(ast|php|css)$">
Header set Cache-Control "public, max-age=3600, must-revalidate"
</FilesMatch>
##### STATIC FILES
<FilesMatch "\\.(png|svg|swf|js|xml)$">
Header set Cache-Control "public, max-age=604800, must-revalidate"
Header unset Last-Modified
</FilesMatch>
##### ETERNAL FILES
<FilesMatch "\\.(ico|jpg|gif|ttf|eot|pdf|flv)$">
Header set Cache-Control "public, max-age=7257600, must-revalidate"
Header unset Last-Modified
</FilesMatch>
</IfModule>
You are specifically unsetting the Last-Modified header. That's the cache validator section. Remove those lines that include:
Header unset Last-Modified
Also, is your css really dynamic? CSS can be huge for a lot of websites. Try to cache that just like any other static content.
All static resources should have either a Last-Modified or ETag header. This will allow browsers to take advantage of the full benefits of caching.