Results for apache : 2

mod_rewrite syntax order

mod_rewrite has some specific ordering rules that affect processing. Before anything gets done, the RewriteEngine On directive needs to be given as this turns on mod_rewrite processing. This should be before any other rewrite directives.

RewriteCond preceding RewriteRule makes that ONE rule subject to the conditional. Any following RewriteRules will be processed as if they were not subject to conditionals.

RewriteEngine On
RewriteCond %{HTTP_REFERER}          ^https?://serverfault\.com(/|$)
RewriteRule $/blog/(.*)\.html        $/blog/$1.sf.html

In this simple case, if the HTTP referrer is from serverfault.com, redirect blog requests to special serverfault pages (we're just that special). However, if the above block had an extra RewriteRule line:

RewriteEngine On
RewriteCond %{HTTP_REFERER}          ^https?://serverfault\.com(/|$)
RewriteRule $/blog/(.*)\.html        $/blog/$1.sf.html
RewriteRule $/blog/(.*)\.jpg         $/blog/$1.sf.jpg

All .jpg files would go to the special serverfault pages, not just the ones with a referrer indicating it came from here. This is clearly not the intent of the how these rules are written. It could be done with multiple RewriteCond rules:

RewriteEngine On
RewriteCond %{HTTP_REFERER}          ^https?://serverfault\.com(/|$)
RewriteRule ^/blog/(.*)\.html        /blog/$1.sf.html
RewriteCond %{HTTP_REFERER}          ^https?://serverfault\.com(/|$)
RewriteRule ^/blog/(.*)\.jpg         /blog/$1.sf.jpg

But probably should be done with some trickier replacement syntax.

RewriteEngine On
RewriteCond %{HTTP_REFERER}                ^https?://serverfault\.com(/|$)
RewriteRule ^/blog/(.*)\.(html|jpg)        /blog/$1.sf.$2

The more complex RewriteRule contains the conditionals for processing. The last parenthetical, (html|jpg) tells RewriteRule to match for either html or jpg, and to represent the matched string as $2 in the rewritten string. This is logically identical to the previous block, with two RewriteCond/RewriteRule pairs, it just does it on two lines instead of four.

Multiple RewriteCond lines are implicitly ANDed, and can be explicitly ORed. To handle referrers from both ServerFault and Super User (explicit OR):

RewriteEngine On
RewriteCond %{HTTP_REFERER}                ^https?://serverfault\.com(/|$)    [OR]
RewriteCond %{HTTP_REFERER}                ^https?://superuser\.com(/|$)
RewriteRule ^/blog/(.*)\.(html|jpg)        /blog/$1.sf.$2

To serve ServerFault referred pages with Chrome browsers (implicit AND):

RewriteEngine On
RewriteCond %{HTTP_REFERER}                ^https?://serverfault\.com(/|$)
RewriteCond %{HTTP_USER_AGENT}             ^Mozilla.*Chrome.*$
RewriteRule ^/blog/(.*)\.(html|jpg)        /blog/$1.sf.$2

RewriteBase is also order specific as it specifies how following RewriteRule directives handle their processing. It is very useful in .htaccess files. If used, it should be the first directive under "RewriteEngine on" in an .htaccess file. Take this example:

RewriteEngine On
RewriteBase /blog
RewriteCond %{HTTP_REFERER}           ^https?://serverfault\.com(/|$)
RewriteRule ^(.*)\.(html|jpg)         $1.sf.$2

This is telling mod_rewrite that this particular URL it is currently handling was arrived by way of http://example.com/blog/ instead of the physical directory path (/home/$Username/public_html/blog) and to treat it accordingly. Because of this, the RewriteRule considers it's string-start to be after the "/blog" in the URL. Here is the same thing written two different ways. One with RewriteBase, the other without:

RewriteEngine On

##Example 1: No RewriteBase##
RewriteCond %{HTTP_REFERER}                                   ^https?://serverfault\.com(/|$)
RewriteRule /home/assdr/public_html/blog/(.*)\.(html|jpg)     $1.sf.$2

##Example 2: With RewriteBase##
RewriteBase /blog
RewriteCond %{HTTP_REFERER}           ^https?://serverfault\.com(/|$)
RewriteRule ^(.*)\.(html|jpg)         $1.sf.$2

As you can see, RewriteBase allows rewrite rules to leverage the web-site path to content rather than the web-server, which can make them more intelligible to those who edit such files. Also, they can make the directives shorter, which has an aesthetic appeal.
RewriteRule matching syntax

RewriteRule itself has a complex syntax for matching strings. I'll cover the flags (things like [PT]) in another section. Because Sysadmins learn by example more often than by reading a man-page I'll give examples and explain what they do.

RewriteRule ^/blog/(.*)$    /newblog/$1

The .* construct matches any single character (.) zero or more times (*). Enclosing it in parenthesis tells it to provide the string that was matched as the $1 variable.

RewriteRule ^/blog/.*/(.*)$  /newblog/$1

In this case, the first .* was NOT enclosed in parens so isn't provided to the rewritten string. This rule removes a directory level on the new blog-site. (/blog/2009/sample.html becomes /newblog/sample.html).

RewriteRule ^/blog/(2008|2009)/(.*)$   /newblog/$2

In this case, the first parenthesis expression sets up a matching group. This becomes $1, which is not needed and therefore not used in the rewritten string.

RewriteRule ^/blog/(2008|2009)/(.*)$   /newblog/$1/$2

In this case, we use $1 in the rewritten string.

RewriteRule ^/blog/(20[0-9][0-9])/(.*)$   /newblog/$1/$2

This rule uses a special bracket syntax that specifies a character range. [0-9] matches the numerals 0 through 9. This specific rule will handle years from 2000 to 2099.

RewriteRule ^/blog/(20[0-9]{2})/(.*)$  /newblog/$1/$2

This does the same thing as the previous rule, but the {2} portion tells it to match the previous character (a bracket expression in this case) two times.

RewriteRule ^/blog/([0-9]{4})/([a-z]*)\.html   /newblog/$1/$2.shtml

This case will match any lower-case letter in the second matching expression, and do so for as many characters as it can. The \. construct tells it to treat the period as an actual period, not the special character it is in previous examples. It will break if the file-name has dashes in it, though.

RewriteRule ^/blog/([0-9]{4})/([-a-z]*)\.html  /newblog/$1/$2.shtml

This traps file-names with dashes in them. However, as - is a special character in bracket expressions, it has to be the first character in the expression.

RewriteRule ^/blog/([0-9]{4})/([-0-9a-zA-Z]*)\.html   /newblog/$1/$2.shtml

This version traps any file name with letters, numbers or the - character in the file-name. This is how you specify multiple character sets in a bracket expression.
RewriteRule flags

The flags on rewrite rules have a host of special meanings and usecases.

RewriteRule ^/blog/([0-9]{4})/([-a-z]*).\html  /newblog/$1/$2.shtml  [L]

The flag is the [L] at the end of the above expression. Multiple flags can be used, separated by a comma. The linked documentation describes each one, but here they are anyway:

L = Last. Stop processing RewriteRules once this one matches. Order counts!
C = Chain. Continue processing the next RewriteRule. If this rule doesn't match, then the next rule won't be executed. More on this later.
E = Set environmental variable. Apache has various environmental variables that can affect web-server behavior.
F = Forbidden. Returns a 403-Forbidden error if this rule matches.
G = Gone. Returns a 410-Gone error if this rule matches.
H = Handler. Forces the request to be handled as if it were the specified MIME-type.
N = Next. Forces the rule to start over again and re-match. BE CAREFUL! Loops can result.
NC = No case. Allows jpg to match both jpg and JPG.
NE = No escape. Prevents the rewriting of special characters (. ? # & etc) into their hex-code equivalents.
NS = No subrequests. If you're using server-side-includes, this will prevent matches to the included files.
P = Proxy. Forces the rule to be handled by mod_proxy. Transparently provide content from other servers, because your web-server fetches it and re-serves it. This is a dangerous flag, as a poorly written one will turn your web-server into an open-proxy and That is Bad.
PT = Pass Through. Take into account Alias statements in RewriteRule matching.
QSA = QSAppend. When the original string contains a query (http://example.com/thing?asp=foo) append the original query string to the rewritten string. Normally it would be discarded. Important for dynamic content.
R = Redirect. Provide an HTTP redirect to the specified URL. Can also provide exact redirect code [R=303]. Very similar to RedirectMatch, which is faster and should be used when possible.
S = Skip. Skip this rule.
T = Type. Specify the mime-type of the returned content. Very similar to the AddType directive.

You know how I said that RewriteCond applies to one and only one rule? Well, you can get around that by chaining.

RewriteEngine On
RewriteCond %{HTTP_REFERER}          ^https?://serverfault\.com(/|$)
RewriteRule ^/blog/(.*)\.html        /blog/$1.sf.html     [C]
RewriteRule ^/blog/(.*)\.jpg         /blog/$1.sf.jpg

Because the first RewriteRule has the Chain flag, the second rewrite-rule will execute when the first does, which is when the previous RewriteCond rule is matched. Handy if Apache regular-expressions make your brain hurt. However, the all-in-one-line method I point to in the first section is faster from an optimization point of view.

RewriteRule ^/blog/([0-9]{4})/([-0-9a-zA-Z]*)\.html   /newblog/$1/$2.shtml

This can be made simpler through flags:

RewriteRule ^/blog/([0-9]{4})/([-0-9a-z]*)\.html   /newblog/$1/$2.shtml   [NC]

Also, some flags also apply to RewriteCond. Notably, NoCase.

RewriteCond %{HTTP_REFERER}        ^https?://serverfault\.com(/|$)     [NC]

Will match "ServerFault.com"

			

# .htaccess Snippets [![Awesome](https://cdn.rawgit.com/sindresorhus/awesome/d7305f38d29fed78fa85652e3a63e154dd8e8829/media/badge.svg)](https://github.com/sindresorhus/awesome)
A collection of useful .htaccess snippets, all in one place.

**Disclaimer**: While dropping the snippet into an `.htaccess` file is most of the time sufficient, there are cases when certain modifications might be required. Use at your own risk.

**IMPORTANT**: Apache 2.4 introduces a few breaking changes, most notably in access control configuration. For more information, check the [upgrading document](https://httpd.apache.org/docs/2.4/upgrading.html) as well as [this issue](https://github.com/phanan/htaccess/issues/2).

## Credits
What we are doing here is mostly collecting useful snippets from all over the interwebs (for example, a good chunk is from [Apache Server Configs](https://github.com/h5bp/server-configs-apache)) into one place. While we’ve been trying to credit where due, things might be missing. If you believe anything here is your work and credits should be given, let us know, or just send a PR.

## Table of Contents
- [Rewrite and Redirection](#rewrite-and-redirection)
    - [Force www](#force-www)
    - [Force www in a Generic Way](#force-www-in-a-generic-way)
    - [Force non-www](#force-non-www)
    - [Force non-www in a Generic Way](#force-non-www-in-a-generic-way)
    - [Force HTTPS](#force-https)
    - [Force HTTPS Behind a Proxy](#force-https-behind-a-proxy)
    - [Force Trailing Slash](#force-trailing-slash)
    - [Remove Trailing Slash](#remove-trailing-slash)
    - [Redirect a Single Page](#redirect-a-single-page)
    - [Redirect Using RedirectMatch](#redirect-using-redirectmatch)
    - [Alias a Single Directory](#alias-a-single-directory)
    - [Alias Paths to Script](#alias-paths-to-script)
    - [Redirect an Entire Site](#redirect-an-entire-site)
    - [Alias "Clean" URLs](#alias-clean-urls)
- [Security](#security)
    - [Deny All Access](#deny-all-access)
    - [Deny All Access Except Yours](#deny-all-access-except-yours)
    - [Allow All Access Except Spammers'](#allow-all-access-except-spammers)
    - [Deny Access to Hidden Files and Directories](#deny-access-to-hidden-files-and-directories)
    - [Deny Access to Backup and Source Files](#deny-access-to-backup-and-source-files)
    - [Disable Directory Browsing](#disable-directory-browsing)
    - [Disable Image Hotlinking](#disable-image-hotlinking)
    - [Disable Image Hotlinking for Specific Domains](#disable-image-hotlinking-for-specific-domains)
    - [Password Protect a Directory](#password-protect-a-directory)
    - [Password Protect a File or Several Files](#password-protect-a-file-or-several-files)
    - [Block Visitors by Referrer](#block-visitors-by-referrer)
    - [Prevent Framing the Site](#prevent-framing-the-site)
- [Performance](#performance)
    - [Compress Text Files](#compress-text-files)
    - [Set Expires Headers](#set-expires-headers)
    - [Turn eTags Off](#turn-etags-off)
- [Miscellaneous](#miscellaneous)
    - [Set PHP Variables](#set-php-variables)
    - [Custom Error Pages](#custom-error-pages)
    - [Force Downloading](#force-downloading)
    - [Prevent Downloading](#prevent-downloading)
    - [Allow Cross-Domain Fonts](#allow-cross-domain-fonts)
    - [Auto UTF-8 Encode](#auto-utf-8-encode)
    - [Switch to Another PHP Version](#switch-to-another-php-version)
    - [Disable Internet Explorer Compatibility View](#disable-internet-explorer-compatibility-view)
    - [Serve WebP Images](#serve-webp-images)

## Rewrite and Redirection
Note: It is assumed that you have `mod_rewrite` installed and enabled.

### Force www
``` apacheconf
RewriteEngine on
RewriteCond %{HTTP_HOST} ^example\.com [NC]
RewriteRule ^(.*)$ http://www.example.com/$1 [L,R=301,NC]
```

### Force www in a Generic Way
``` apacheconf
RewriteCond %{HTTP_HOST} !^$
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteCond %{HTTPS}s ^on(s)|
RewriteRule ^ http%1://www.%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
```
This works for _any_ domain. [Source](https://stackoverflow.com/questions/4916222/htaccess-how-to-force-www-in-a-generic-way)

### Force non-www
It’s [still](http://www.sitepoint.com/domain-www-or-no-www/) [open](https://devcenter.heroku.com/articles/apex-domains) [for](http://yes-www.org/) [debate](http://no-www.org/) whether www or non-www is the way to go, so if you happen to be a fan of bare domains, here you go:
``` apacheconf
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.example\.com [NC]
RewriteRule ^(.*)$ http://example.com/$1 [L,R=301]
```

### Force non-www in a Generic Way
``` apacheconf
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.
RewriteCond %{HTTPS}s ^on(s)|off
RewriteCond http%1://%{HTTP_HOST} ^(https?://)(www\.)?(.+)$
RewriteRule ^ %1%3%{REQUEST_URI} [R=301,L]
```

### Force HTTPS
``` apacheconf
RewriteEngine on
RewriteCond %{HTTPS} !on
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}

# Note: It’s also recommended to enable HTTP Strict Transport Security (HSTS)
# on your HTTPS website to help prevent man-in-the-middle attacks.
# See https://developer.mozilla.org/en-US/docs/Web/Security/HTTP_strict_transport_security
<IfModule mod_headers.c>
    Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains"
</IfModule>
```

### Force HTTPS Behind a Proxy
Useful if you have a proxy in front of your server performing TLS termination.
``` apacheconf
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}
```

### Force Trailing Slash
``` apacheconf
RewriteCond %{REQUEST_URI} /+[^\.]+$
RewriteRule ^(.+[^/])$ %{REQUEST_URI}/ [R=301,L]
```

### Remove Trailing Slash
This snippet will redirect paths ending in slashes to their non-slash-terminated counterparts (except for actual directories), e.g. `http://www.example.com/blog/` to `http://www.example.com/blog`. This is important for SEO, since it’s [recommended](http://overit.com/blog/canonical-urls) to have a canonical URL for every page.
``` apacheconf
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} (.+)/$
RewriteRule ^ %1 [R=301,L]
```
[Source](https://stackoverflow.com/questions/21417263/htaccess-add-remove-trailing-slash-from-url#27264788)

### Redirect a Single Page
``` apacheconf
Redirect 301 /oldpage.html http://www.example.com/newpage.html
Redirect 301 /oldpage2.html http://www.example.com/folder/
```
[Source](http://css-tricks.com/snippets/htaccess/301-redirects/)

### Redirect Using RedirectMatch
``` apacheconf
RedirectMatch 301 /subdirectory(.*) http://www.newsite.com/newfolder/$1
RedirectMatch 301 ^/(.*).htm$ /$1.html
RedirectMatch 301 ^/200([0-9])/([^01])(.*)$ /$2$3
RedirectMatch 301 ^/category/(.*)$ /$1
RedirectMatch 301 ^/(.*)/htaccesselite-ultimate-htaccess-article.html(.*) /htaccess/htaccess.html
RedirectMatch 301 ^/(.*).html/1/(.*) /$1.html$2
RedirectMatch 301 ^/manual/(.*)$ http://www.php.net/manual/$1
RedirectMatch 301 ^/dreamweaver/(.*)$ /tools/$1
RedirectMatch 301 ^/z/(.*)$ http://static.askapache.com/$1
```
[Source](http://www.askapache.com/htaccess/301-redirect-with-mod_rewrite-or-redirectmatch.html#301_Redirects_RedirectMatch)

### Alias a Single Directory
``` apacheconf
RewriteEngine On
RewriteRule ^source-directory/(.*) /target-directory/$1 [R=301,L]
```

### Alias Paths To Script
``` apacheconf
FallbackResource /index.fcgi
```
This example has an `index.fcgi` file in some directory, and any requests within that directory that fail to resolve a filename/directory will be sent to the `index.fcgi` script. It’s good if you want `baz.foo/some/cool/path` to be handled by `baz.foo/index.fcgi` (which also supports requests to `baz.foo`) while maintaining `baz.foo/css/style.css` and the like. Get access to the original path from the PATH_INFO environment variable, as exposed to your scripting environment.

``` apacheconf
RewriteEngine On
RewriteRule ^$ index.fcgi/ [QSA,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.fcgi/$1 [QSA,L]
```
This is a less efficient version of the FallbackResource directive (because using `mod_rewrite` is more complex than just handling the `FallbackResource` directive), but it’s also more flexible.

### Redirect an Entire Site
``` apacheconf
Redirect 301 / http://newsite.com/
```
This way does it with links intact. That is `www.oldsite.com/some/crazy/link.html` will become `www.newsite.com/some/crazy/link.html`. This is extremely helpful when you are just “moving” a site to a new domain. [Source](http://css-tricks.com/snippets/htaccess/301-redirects/)

### Alias “Clean” URLs
This snippet lets you use “clean” URLs -- those without a PHP extension, e.g. `example.com/users` instead of `example.com/users.php`.
``` apacheconf
RewriteEngine On
RewriteCond %{SCRIPT_FILENAME} !-d
RewriteRule ^([^.]+)$ $1.php [NC,L]
```
[Source](http://www.abeautifulsite.net/access-pages-without-the-php-extension-using-htaccess/)

## Security
### Deny All Access
``` apacheconf
## Apache 2.2
Deny from all

## Apache 2.4
# Require all denied
```

But wait, this will lock you out from your content as well! Thus introducing...

### Deny All Access Except Yours
``` apacheconf
## Apache 2.2
Order deny,allow
Deny from all
Allow from xxx.xxx.xxx.xxx

## Apache 2.4
# Require all denied
# Require ip xxx.xxx.xxx.xxx
```
`xxx.xxx.xxx.xxx` is your IP. If you replace the last three digits with `0/12` for example, this will specify a range of IPs within the same network, thus saving you the trouble to list all allowed IPs separately. [Source](http://speckyboy.com/2013/01/08/useful-htaccess-snippets-and-hacks/)

Now of course there's a reversed version:

### Allow All Access Except Spammers'
``` apacheconf
## Apache 2.2
Order deny,allow
Deny from xxx.xxx.xxx.xxx
Deny from xxx.xxx.xxx.xxy

## Apache 2.4
# Require all granted
# Require not ip xxx.xxx.xxx.xxx
# Require not ip xxx.xxx.xxx.xxy
```

### Deny Access to Hidden Files and Directories
Hidden files and directories (those whose names start with a dot `.`) should most, if not all, of the time be secured. For example: `.htaccess`, `.htpasswd`, `.git`, `.hg`...
``` apacheconf
RewriteCond %{SCRIPT_FILENAME} -d [OR]
RewriteCond %{SCRIPT_FILENAME} -f
RewriteRule "(^|/)\." - [F]
```

Alternatively, you can just raise a “Not Found” error, giving the attacker no clue:
``` apacheconf
RedirectMatch 404 /\..*$
```

### Deny Access to Backup and Source Files
These files may be left by some text/HTML editors (like Vi/Vim) and pose a great security danger if exposed to public.
``` apacheconf
<FilesMatch "(\.(bak|config|dist|fla|inc|ini|log|psd|sh|sql|swp)|~)$">
    ## Apache 2.2
    Order allow,deny
    Deny from all
    Satisfy All

    ## Apache 2.4
    # Require all denied
</FilesMatch>
```
[Source](https://github.com/h5bp/server-configs-apache)

### Disable Directory Browsing
``` apacheconf
Options All -Indexes
```

### Disable Image Hotlinking
``` apacheconf
RewriteEngine on
# Remove the following line if you want to block blank referrer too
RewriteCond %{HTTP_REFERER} !^$

RewriteCond %{HTTP_REFERER} !^https?://(.+\.)?example.com [NC]
RewriteRule \.(jpe?g|png|gif|bmp)$ - [NC,F,L]

# If you want to display a “blocked” banner in place of the hotlinked image,
# replace the above rule with:
# RewriteRule \.(jpe?g|png|gif|bmp) http://example.com/blocked.png [R,L]
```

### Disable Image Hotlinking for Specific Domains
Sometimes you want to disable image hotlinking from some bad guys only.
``` apacheconf
RewriteEngine on
RewriteCond %{HTTP_REFERER} ^https?://(.+\.)?badsite\.com [NC,OR]
RewriteCond %{HTTP_REFERER} ^https?://(.+\.)?badsite2\.com [NC,OR]
RewriteRule \.(jpe?g|png|gif|bmp)$ - [NC,F,L]

# If you want to display a “blocked” banner in place of the hotlinked image,
# replace the above rule with:
# RewriteRule \.(jpe?g|png|gif|bmp) http://example.com/blocked.png [R,L]
```

### Password Protect a Directory
First you need to create a `.htpasswd` file somewhere in the system:
``` bash
htpasswd -c /home/fellowship/.htpasswd boromir
```

Then you can use it for authentication:
``` apacheconf
AuthType Basic
AuthName "One does not simply"
AuthUserFile /home/fellowship/.htpasswd
Require valid-user
```

### Password Protect a File or Several Files
``` apacheconf
AuthName "One still does not simply"
AuthType Basic
AuthUserFile /home/fellowship/.htpasswd

<Files "one-ring.o">
Require valid-user
</Files>

<FilesMatch ^((one|two|three)-rings?\.o)$>
Require valid-user
</FilesMatch>
```

### Block Visitors by Referrer
This denies access for all users who are coming from (referred by) a specific domain.
[Source](http://www.htaccess-guide.com/deny-visitors-by-referrer/)
``` apacheconf
RewriteEngine on
# Options +FollowSymlinks
RewriteCond %{HTTP_REFERER} somedomain\.com [NC,OR]
RewriteCond %{HTTP_REFERER} anotherdomain\.com
RewriteRule .* - [F]
```

### Prevent Framing the Site
This prevents the website to be framed (i.e. put into an `iframe` tag), when still allows framing for a specific URI.
``` apacheconf
SetEnvIf Request_URI "/starry-night" allow_framing=true
Header set X-Frame-Options SAMEORIGIN env=!allow_framing
```

## Performance
### Compress Text Files
``` apacheconf
<IfModule mod_deflate.c>

    # Force compression for mangled headers.
    # https://developer.yahoo.com/blogs/ydn/pushing-beyond-gzipping-25601.html
    <IfModule mod_setenvif.c>
        <IfModule mod_headers.c>
            SetEnvIfNoCase ^(Accept-EncodXng|X-cept-Encoding|X{15}|~{15}|-{15})$ ^((gzip|deflate)\s*,?\s*)+|[X~-]{4,13}$ HAVE_Accept-Encoding
            RequestHeader append Accept-Encoding "gzip,deflate" env=HAVE_Accept-Encoding
        </IfModule>
    </IfModule>

    # Compress all output labeled with one of the following MIME-types
    # (for Apache versions below 2.3.7, you don't need to enable `mod_filter`
    #  and can remove the `<IfModule mod_filter.c>` and `</IfModule>` lines
    #  as `AddOutputFilterByType` is still in the core directives).
    <IfModule mod_filter.c>
        AddOutputFilterByType DEFLATE application/atom+xml \
                                      application/javascript \
                                      application/json \
                                      application/rss+xml \
                                      application/vnd.ms-fontobject \
                                      application/x-font-ttf \
                                      application/x-web-app-manifest+json \
                                      application/xhtml+xml \
                                      application/xml \
                                      font/opentype \
                                      image/svg+xml \
                                      image/x-icon \
                                      text/css \
                                      text/html \
                                      text/plain \
                                      text/x-component \
                                      text/xml
    </IfModule>

</IfModule>
```
[Source](https://github.com/h5bp/server-configs-apache)


### Set Expires Headers
_Expires headers_ tell the browser whether they should request a specific file from the server or just grab it from the cache. It is advisable to set static content's expires headers to something far in the future.

If you don’t control versioning with filename-based cache busting, consider lowering the cache time for resources like CSS and JS to something like 1 week. [Source](https://github.com/h5bp/server-configs-apache)
``` apacheconf
<IfModule mod_expires.c>
    ExpiresActive on
    ExpiresDefault                                      "access plus 1 month"

  # CSS
    ExpiresByType text/css                              "access plus 1 year"

  # Data interchange
    ExpiresByType application/json                      "access plus 0 seconds"
    ExpiresByType application/xml                       "access plus 0 seconds"
    ExpiresByType text/xml                              "access plus 0 seconds"

  # Favicon (cannot be renamed!)
    ExpiresByType image/x-icon                          "access plus 1 week"

  # HTML components (HTCs)
    ExpiresByType text/x-component                      "access plus 1 month"

  # HTML
    ExpiresByType text/html                             "access plus 0 seconds"

  # JavaScript
    ExpiresByType application/javascript                "access plus 1 year"

  # Manifest files
    ExpiresByType application/x-web-app-manifest+json   "access plus 0 seconds"
    ExpiresByType text/cache-manifest                   "access plus 0 seconds"

  # Media
    ExpiresByType audio/ogg                             "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 video/mp4                             "access plus 1 month"
    ExpiresByType video/ogg                             "access plus 1 month"
    ExpiresByType video/webm                            "access plus 1 month"

  # Web feeds
    ExpiresByType application/atom+xml                  "access plus 1 hour"
    ExpiresByType application/rss+xml                   "access plus 1 hour"

  # Web fonts
    ExpiresByType application/font-woff2                "access plus 1 month"
    ExpiresByType application/font-woff                 "access plus 1 month"
    ExpiresByType application/vnd.ms-fontobject         "access plus 1 month"
    ExpiresByType application/x-font-ttf                "access plus 1 month"
    ExpiresByType font/opentype                         "access plus 1 month"
    ExpiresByType image/svg+xml                         "access plus 1 month"
</IfModule>
```

### Turn eTags Off
By removing the `ETag` header, you disable caches and browsers from being able to validate files, so they are forced to rely on your `Cache-Control` and `Expires` header. [Source](http://www.askapache.com/htaccess/apache-speed-etags.html)
``` apacheconf
<IfModule mod_headers.c>
    Header unset ETag
</IfModule>
FileETag None
```

## Miscellaneous

### Set PHP Variables
``` apacheconf
php_value <key> <val>

# For example:
php_value upload_max_filesize 50M
php_value max_execution_time 240
```

### Custom Error Pages
``` apacheconf
ErrorDocument 500 "Houston, we have a problem."
ErrorDocument 401 http://error.example.com/mordor.html
ErrorDocument 404 /errors/halflife3.html
```

### Force Downloading
Sometimes you want to force the browser to download some content instead of displaying it.
``` apacheconf
<Files *.md>
    ForceType application/octet-stream
    Header set Content-Disposition attachment
</Files>
```

Now there is a yang to this yin:

### Prevent Downloading
Sometimes you want to force the browser to display some content instead of downloading it.
``` apacheconf
<FilesMatch "\.(tex|log|aux)$">
    Header set Content-Type text/plain
</FilesMatch>
```

### Allow Cross-Domain Fonts
CDN-served webfonts might not work in Firefox or IE due to [CORS](https://en.wikipedia.org/wiki/Cross-origin_resource_sharing). This snippet solves the problem.
``` apacheconf
<IfModule mod_headers.c>
    <FilesMatch "\.(eot|otf|ttc|ttf|woff|woff2)$">
        Header set Access-Control-Allow-Origin "*"
    </FilesMatch>
</IfModule>
```
[Source](https://github.com/h5bp/server-configs-apache/issues/32)

### Auto UTF-8 Encode
Your text content should always be UTF-8 encoded, no?
``` apacheconf
# Use UTF-8 encoding for anything served text/plain or text/html
AddDefaultCharset utf-8

# Force UTF-8 for a number of file formats
AddCharset utf-8 .atom .css .js .json .rss .vtt .xml
```
[Source](https://github.com/h5bp/server-configs-apache)

### Switch to Another PHP Version
If you’re on a shared host, chances are there are more than one version of PHP installed, and sometimes you want a specific version for your website. The following snippet should switch the PHP version for you.

``` apacheconf
AddHandler application/x-httpd-php56 .php

# Alternatively, you can use AddType
AddType application/x-httpd-php56 .php
```

### Disable Internet Explorer Compatibility View
Compatibility View in IE may affect how some websites are displayed. The following snippet should force IE to use the Edge Rendering Engine and disable the Compatibility View.

``` apacheconf
<IfModule mod_headers.c>
    BrowserMatch MSIE is-msie
    Header set X-UA-Compatible IE=edge env=is-msie
</IfModule>
```

### Serve WebP Images
If [WebP images](https://developers.google.com/speed/webp/?csw=1) are supported and an image with a .webp extension and the same name is found at the same place as the jpg/png image that is going to be served, then the WebP image is served instead.

``` apacheconf
RewriteEngine On
RewriteCond %{HTTP_ACCEPT} image/webp
RewriteCond %{DOCUMENT_ROOT}/$1.webp -f
RewriteRule (.+)\.(jpe?g|png)$ $1.webp [T=image/webp,E=accept:1]
```
[Source](https://github.com/vincentorback/WebP-images-with-htaccess)