Original: https:\/\/www.liquidweb.com\/kb\/how-to-configure-apache-2-to-control-browser-caching\/<\/p>\n\n\n\n
by\u00a0Jason Potter\u00a0|\u00a0Updated:\u00a0June 4, 2020
Reading Time:\u00a09\u00a0minutes<\/p>\n\n\n\n
Today we are configuring browser caching control on common Apache 2\u00a0Dedicated servers\u00a0or\u00a0VPS servers. Caching is a great tool to reduce server resource consumption, bandwidth utilization and provide a faster end-user experience to visitors. To get familiar with caching concepts, simply review our \u2018What is Caching<\/em>?\u2019 tutorial.<\/p>\n\n\n\n Preflight Check<\/strong><\/p>\n\n\n\n This article covers all Apache 2 servers running the mod_expires and mod_headers Apache modules. This includes, but is not limited to, both traditional Dedicated Servers and Cloud VPS servers running a number of different Linux distributions:<\/p>\n\n\n\n Note:<\/p>\n\n\n\n Self-managed servers running a similar Linux distribution can take advantage of this article. However, instructions are not specifically provided for Self-managed configurations.<\/p>\n\n\n\n The article assumes familiarity with the following basic system administration concepts:<\/p>\n\n\n\n Verify Modules<\/strong><\/p>\n\n\n\n Our servers generally include both the mod_expires and mod_headers modules needed for browser cache control. However, before we configure the directives, we must first ensure the modules are installed and Apache 2 is ready to accept the directives. Verification is simple. We will be using the apachectl -M<\/em> command to list the installed Apache modules while piping the output through the grep module_name<\/em> command to filter the results down to showing only modules with the provided module_name, likes so:<\/p>\n\n\n\n Verifying mod_headers<\/strong> (also known as Headers_module) by copying & pasting the following command.<\/p>\n\n\n\n apachectl -M | grep header<\/p>\n\n\n\n \u2026 will return:<\/p>\n\n\n\n headers_module (shared)<\/p>\n\n\n\n Verifying mod_expires<\/strong> (also known as expires module) by copying and pasting the following command.<\/p>\n\n\n\n apachectl -M | grep expires<\/p>\n\n\n\n \u2026 will return:<\/p>\n\n\n\n expires_module (shared)<\/p>\n\n\n\n These modules must be present in the output when running the command. If they do not show up in the output, it will simply be blank, which indicates the modules are not installed. If the modules are missing then we will need to install them before we can continue.<\/p>\n\n\n\n Configuration Directives<\/strong><\/p>\n\n\n\n We can use the following example of a generic configuration that serves to reduce the strain on server resources by prolonging the cache duration of common static files. These types of files typically do not change between visits. So, they do not need to be downloaded on every visit. Modern browsers are equipped to accept instructions from web servers that provide suggestions for how long content should be cached. This example works well for most sites. However, you may need to add\/remove file types or adjust lifespan as needed for your particular content.<\/p>\n\n\n\n <IfModule mod_expires.c> Explanation of Each Directive<\/p>\n\n\n\n These are opening tags and will only process directives between these if the module, mod_expires, is installed on the server.<\/p>\n\n\n\n <IfModule mod_expires.c> … <\/IfModule><\/p>\n\n\n\n Download all files only if the cache has not been accessed in more than 2 days.<\/p>\n\n\n\n ExpiresDefault “access plus 2 days” ExpiresDefault “access plus 2 days” Download files only if the cached copy hasn\u2019t been accessed in 10 minutes.<\/p>\n\n\n\n ExpiresByType text\/html “access plus 600 seconds”<\/p>\n\n\n\n You can find a more robust explanation of these directives and all that expires_module offers in the Apache mod_expires Online Docs<\/a>.<\/p>\n\n\n\n Implementation<\/strong><\/p>\n\n\n\n Now that we have an understanding of how these directives can be configured, we need to decide on our method of implementation. There are generally two methods of implementation for these directives. We classify these as either Portable or Include Methods.<\/p>\n\n\n\n Portable Method<\/p>\n\n\n\n The Portable Method uses .htaccess files to manage which directories are affected by the mod_expires configuration we are settings. These are handled like any other .htaccess file changes.<\/p>\n\n\n\n There is a small bottleneck warning associated with .htaccess files. This caution is not specific to mod_expires and is an overall Apache alert including .htaccess files in general. In order for .htaccess files to work, Apache must scan every directory leading up to a targeted file looking for and applying any .htaccess files it finds along the way. This can create an I\/O bottleneck on some server configurations. We recommend using the Include Method on all Cloud VPS Servers to avoid this type of problem.<\/p>\n\n\n\n Include Method<\/p>\n\n\n\n In contrast to the Portable Method, the Include Method takes advantage of the Apache includes a system. Apache only reads include files at startup so this prevents the I\/O Bottleneck discussed above in the Portable Method section.<\/p>\n\n\n\n There are generally two ways to use the Include Method:\u00a0Globally\u00a0<\/strong>or\u00a0Per Website<\/strong>. Either method requires locating and modifying the correct include files on the server. The correct files to modify is dependent on both distribution and server management software. We will discuss the correct locations for both methods on the various Liquid Web CentOS servers we support and listed in the\u00a0Preflight Check<\/strong>\u00a0section above.<\/p>\n\n\n\n Global Includes<\/p>\n\n\n\n Applying the mod_expires directives globally is straight forward. It will have the effect of enabling the desired directives over the entire server, affecting every site running through Apache.<\/p>\n\n\n\n Core-managed CentOS 6 & 7 Servers<\/strong><\/p>\n\n\n\n vim \/etc\/httpd\/conf.d\/expire.conf<\/p>\n\n\n\n <IfModule mod_expires.c> Service httpd reload<\/p>\n\n\n\n Fully managed CentOS 6 & 7 cPanel Servers<\/strong><\/p>\n\n\n\n vim \/usr\/local\/apache\/conf\/includes\/pre_virtualhost_global.conf<\/p>\n\n\n\n <IfModule mod_expires.c> \/scripts\/restartsrv_apache<\/p>\n\n\n\n If Running EasyApache 4: Restart Apache PHP-FPM Service<\/p>\n\n\n\n \/scripts\/restartsrv_apache_php_fpm<\/p>\n\n\n\n Fully managed CentOS 7 Plesk Onyx 17 Linux Servers<\/strong><\/p>\n\n\n\n vim \/etc\/httpd\/conf.d\/expire.conf<\/p>\n\n\n\n <IfModule mod_expires.c> Service httpd restart<\/p>\n\n\n\n Per Website Includes<\/p>\n\n\n\n We can also use Apache includes on a per virtual host level to enable browser caching on an individual website basis. We\u2019ll go over how to configure these on our CentOS systems below.<\/p>\n\n\n\n Note:<\/p>\n\n\n\n Each website has two<\/em> virtual hosts, one for HTTP (port 80) connections and another for HTTPS (port 443) connections. Each virtual host is independent of one another. Adding a change to the HTTP virtual host will not automatically apply to the HTTPS virtual host and vice versa.<\/p>\n\n\n\n Core-managed CentOS 6 & 7 Servers<\/strong><\/p>\n\n\n\n The exact method of site management on Core-managed servers is left up to the server owner. This can vary dramatically depending on the person. We will use the default SSL site configuration file as an example on how to configure the Per Website includes for browser caching. Once you locate the necessary site\u2019s configuration file, follow these steps:<\/p>\n\n\n\n vim \/etc\/httpd\/conf.d\/ssl.conf <VirtualHost _default_:443> <VirtualHost _default_:443> service httpd restart<\/p>\n\n\n\n Fully managed CentOS 6 & 7 cPanel Servers<\/strong><\/p>\n\n\n\n cPanel provides a rich template system that can be used to modify Apache behavior as needed. There is a specific directory structure needed to ensure our modifications persist through updates, upgrades, and restarts. This system works the same way on both EasyApache 3 and EasyApache 4 systems.<\/p>\n\n\n\n Each site can handle its set of custom includes files. These need to be located in the following locations:<\/p>\n\n\n\n There are three variables in the path above that need to be reconciled:<\/p>\n\n\n\n HTTP Virtual Host:<\/p>\n\n\n\n mkdir -p \/etc\/apache2\/conf.d\/userdata\/std\/2_4\/myuser\/example.com\/<\/p>\n\n\n\n HTTPS Virtual Host:<\/p>\n\n\n\n mkdir -p \/etc\/apache2\/conf.d\/userdata\/ssl\/2_4\/myuser\/example.com\/<\/p>\n\n\n\n vim \/etc\/apache2\/conf.d\/userdata\/std\/2_4\/myuser\/example.com\/expires.conf<\/p>\n\n\n\n HTTPS Virtual Host: <IfModule mod_expires.c> \/usr\/local\/cpanel\/scripts\/rebuildhttpdconf<\/p>\n\n\n\n There are additional methods for handling virtual hosts in cPanel. Applying includes to all hosts or all HTTPS hosts or even all hosts by one user. For a much more in-depth explanation of the cPanel Virtual Host Include system,\u00a0visit\u00a0the Official cPanel Online Docs.<\/p>\n\n\n\n Fully managed CentOS 7 Plesk Onyx 17 Linux Servers<\/strong><\/p>\n\n\n\n Plesk provides a robust include and template system for modification of virtual host entries on an individual virtual host basis. These are done in the following files:<\/p>\n\n\n\n Note:<\/p>\n\n\n\n We will need to replace example.com with your domain name (minus www. prefix). The directory structure here should already exist. However, these vhost.conf and vhost_ssl.conf files do not exist by default and will need to be created.<\/p>\n\n\n\n touch \/var\/www\/vhosts\/system\/example.com\/conf\/vhost.conf<\/p>\n\n\n\n HTTPS Virtual Host: <IfModule mod_expires.c> The Plesk templates and includes systems are very robust and permits the integration of many other common Apache directives. Visit the Plesk Onyx Online Documentation<\/a> to learn more about leveraging its capabilities.<\/p>\n","protected":false},"excerpt":{"rendered":" Original: https:\/\/www.liquidweb.com\/kb\/how-to-configure-apache-2-to-control-browser-caching\/ by\u00a0Jason Potter\u00a0|\u00a0Updated:\u00a0June 4, 2020Reading Time:\u00a09\u00a0minutes Today we are configuring browser caching control on common Apache 2\u00a0Dedicated servers\u00a0or\u00a0VPS servers. Caching is a great tool to reduce server resource consumption, bandwidth utilization and provide a faster end-user experience to visitors. To get familiar with caching concepts, simply review our \u2018What is Caching?\u2019 tutorial. Preflight Check Read More<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[104,5],"tags":[],"class_list":["post-1172","post","type-post","status-publish","format-standard","hentry","category-apache","category-linux"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/SUMMALAI.COM\/index.php?rest_route=\/wp\/v2\/posts\/1172","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/SUMMALAI.COM\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/SUMMALAI.COM\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/SUMMALAI.COM\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/SUMMALAI.COM\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1172"}],"version-history":[{"count":0,"href":"https:\/\/SUMMALAI.COM\/index.php?rest_route=\/wp\/v2\/posts\/1172\/revisions"}],"wp:attachment":[{"href":"https:\/\/SUMMALAI.COM\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1172"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/SUMMALAI.COM\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1172"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/SUMMALAI.COM\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1172"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
# Turn on the module.
ExpiresActive on
# Set the default expiry times.
ExpiresDefault “access plus 2 days”
ExpiresByType image\/jpg “access plus 1 month”
ExpiresByType image\/gif “access plus 1 month”
ExpiresByType image\/jpeg “access plus 1 month”
ExpiresByType image\/png “access plus 1 month”
ExpiresByType text\/css “access plus 1 month”
ExpiresByType text\/javascript “access plus 1 month”
ExpiresByType application\/javascript “access plus 1 month”
ExpiresByType application\/x-shockwave-flash “access plus 1 month”
ExpiresByType text\/css “now plus 1 month”
ExpiresByType image\/ico “access plus 1 month”
ExpiresByType image\/x-icon “access plus 1 month”
ExpiresByType text\/html “access plus 600 seconds”
<\/IfModule><\/p>\n\n\n\n
Download files only if the cached file has not been accessed in more than 1 month. This covers jpg, jpeg, gif, png, css, javascript, flash, ico, and x-icon file types.<\/p>\n\n\n\n
ExpiresByType image\/jpg “access plus 1 month”
ExpiresByType image\/gif “access plus 1 month”
ExpiresByType image\/jpeg “access plus 1 month”
ExpiresByType image\/png “access plus 1 month”
ExpiresByType text\/css “access plus 1 month”
ExpiresByType text\/javascript “access plus 1 month”
ExpiresByType application\/javascript “access plus 1 month”
ExpiresByType application\/x-shockwave-flash “access plus 1 month”
ExpiresByType text\/css “now plus 1 month”
ExpiresByType image\/ico “access plus 1 month”
ExpiresByType image\/x-icon “access plus 1 month”<\/p>\n\n\n\n
The file should look like the following:<\/li><\/ol>\n\n\n\n
# Turn on the module.
ExpiresActive on
# Set the default expiry times.
ExpiresDefault “access plus 2 days”
ExpiresByType image\/jpg “access plus 1 month”
ExpiresByType image\/gif “access plus 1 month”
ExpiresByType image\/jpeg “access plus 1 month”
ExpiresByType image\/png “access plus 1 month”
ExpiresByType text\/javascript “access plus 1 month”
ExpiresByType application\/javascript “access plus 1 month”
ExpiresByType application\/x-shockwave-flash “access plus 1 month”
ExpiresByType text\/css “now plus 1 month”
ExpiresByType image\/ico “access plus 1 month”
ExpiresByType image\/x-icon “access plus 1 month”
ExpiresByType text\/html “access plus 600 seconds”
<\/IfModule><\/p>\n\n\n\n
Your file may contain additional directives in this file, but the bottom should look like this:
<\/li><\/ol>\n\n\n\n
# Turn on the module.
ExpiresActive on
# Set the default expiry times.
ExpiresDefault “access plus 2 days”
ExpiresByType image\/jpg “access plus 1 month”
ExpiresByType image\/gif “access plus 1 month”
ExpiresByType image\/jpeg “access plus 1 month”
ExpiresByType image\/png “access plus 1 month”
ExpiresByType text\/javascript “access plus 1 month”
ExpiresByType application\/javascript “access plus 1 month”
ExpiresByType application\/x-shockwave-flash “access plus 1 month”
ExpiresByType text\/css “now plus 1 month”
ExpiresByType image\/ico “access plus 1 month”
ExpiresByType image\/x-icon “access plus 1 month”
ExpiresByType text\/html “access plus 600 seconds”
<\/IfModule><\/p>\n\n\n\n
The file should look like the following:<\/li><\/ol>\n\n\n\n
# Turn on the module.
ExpiresActive on
# Set the default expiry times.
ExpiresDefault “access plus 2 days”
ExpiresByType image\/jpg “access plus 1 month”
ExpiresByType image\/gif “access plus 1 month”
ExpiresByType image\/jpeg “access plus 1 month”
ExpiresByType image\/png “access plus 1 month”
ExpiresByType text\/javascript “access plus 1 month”
ExpiresByType application\/javascript “access plus 1 month”
ExpiresByType application\/x-shockwave-flash “access plus 1 month”
ExpiresByType text\/css “now plus 1 month”
ExpiresByType image\/ico “access plus 1 month”
ExpiresByType image\/x-icon “access plus 1 month”
ExpiresByType text\/html “access plus 600 seconds”
<\/IfModule><\/p>\n\n\n\n
2. Locate the Virtual Host line for the site within its config file. A Virtual Host Stanza looks like the following example:<\/p>\n\n\n\n
\u2026
<\/VirtualHost
3. Apply the needed mod_expires directives between the virtual host lines.
The results should look similar to the following example:<\/p>\n\n\n\n
\u2026
<IfModule mod_expires.c>
# Turn on the module.
ExpiresActive on
# Set the default expiry times.
ExpiresDefault “access plus 2 days”
ExpiresByType image\/jpg “access plus 1 month”
ExpiresByType image\/gif “access plus 1 month”
ExpiresByType image\/jpeg “access plus 1 month”
ExpiresByType image\/png “access plus 1 month”
ExpiresByType text\/javascript “access plus 1 month”
ExpiresByType application\/javascript “access plus 1 month”
ExpiresByType application\/x-shockwave-flash “access plus 1 month”
ExpiresByType text\/css “now plus 1 month”
ExpiresByType image\/ico “access plus 1 month”
ExpiresByType image\/x-icon “access plus 1 month”
ExpiresByType text\/html “access plus 600 seconds”
<\/IfModule>
\u2026
<\/VirtualHost>
4. Restart The Apache Service<\/p>\n\n\n\n
HTTP Virtual Hosts:
\/etc\/apache2\/conf.d\/userdata\/std\/2_4\/<USER>\/<DOMAIN>\/<INCLUDENAME>.conf<\/p>\n\n\n\n
HTTPS Virtual Hosts:
\/etc\/apache2\/conf.d\/userdata\/ssl\/2_4\/<USER>\/<DOMAIN>\/<INCLUDENAME>.conf<\/p>\n\n\n\n
HTTP Virtual Host:<\/li><\/ol>\n\n\n\n
vim \/etc\/apache2\/conf.d\/userdata\/ssl\/2_4\/myuser\/example.com\/expires.conf<\/p>\n\n\n\n
# Turn on the module.
ExpiresActive on
# Set the default expiry times.
ExpiresDefault “access plus 2 days”
ExpiresByType image\/jpg “access plus 1 month”
ExpiresByType image\/gif “access plus 1 month”
ExpiresByType image\/jpeg “access plus 1 month”
ExpiresByType image\/png “access plus 1 month”
ExpiresByType text\/javascript “access plus 1 month”
ExpiresByType application\/javascript “access plus 1 month”
ExpiresByType application\/x-shockwave-flash “access plus 1 month”
ExpiresByType text\/css “now plus 1 month”
ExpiresByType image\/ico “access plus 1 month”
ExpiresByType image\/x-icon “access plus 1 month”
ExpiresByType text\/html “access plus 600 seconds”
<\/IfModule><\/p>\n\n\n\n
\/usr\/local\/cpanel\/scripts\/restartsrv_apache<\/li>
\/usr\/local\/cpanel\/scripts\/restartsrv_apache_php_fpm<\/li><\/ol>\n\n\n\n
\/var\/www\/vhosts\/system\/example.com\/conf\/vhost_ssl.conf<\/p>\n\n\n\n
HTTP Virtual Host:<\/li><\/ol>\n\n\n\n
touch \/var\/www\/vhosts\/system\/example.com\/conf\/vhost_ssl.conf<\/p>\n\n\n\n
# Turn on the module.
ExpiresActive on
# Set the default expiry times.
ExpiresDefault “access plus 2 days”
ExpiresByType image\/jpg “access plus 1 month”
ExpiresByType image\/gif “access plus 1 month”
ExpiresByType image\/jpeg “access plus 1 month”
ExpiresByType image\/png “access plus 1 month”
ExpiresByType text\/javascript “access plus 1 month”
ExpiresByType application\/javascript “access plus 1 month”
ExpiresByType application\/x-shockwave-flash “access plus 1 month”
ExpiresByType text\/css “now plus 1 month”
ExpiresByType image\/ico “access plus 1 month”
ExpiresByType image\/x-icon “access plus 1 month”
ExpiresByType text\/html “access plus 600 seconds”
<\/IfModule><\/p>\n\n\n\n
\/usr\/local\/psa\/admin\/sbin\/httpdmng –reconfigure-domain example.com<\/li>
service httpd restart<\/li><\/ol>\n\n\n\n