How should I use the <If> directive in .htaccess?

I'm trying to add a conditional statement using Apache's If directive in my .htaccess file.

I have referenced this page http://httpd.apache.org/docs/trunk/mod/core.html#if but it doesn't elaborate much / give many examples. Two incomplete examples it gives are:

<If %{REQUEST_METHOD} IN GET,HEAD,OPTIONS> 

and

<If "$req{Host} = ''"> 

So I've tried to add this to my .htaccess file:

<If %{SERVER_PORT} IN GET,HEAD,OPTIONS>
   #nothing here yet
</If>

But I keep getting Error 500 when I try and load the page. This is on my local install, and it was working fine previously (or if I remove that code). I believe I have AllowOverride All set up globally, and the context for the If directive should let it be present in .htaccess ("Context: server config, virtual host, directory, .htaccess").

Can someone give me some examples of how to properly use the <If> directive, or some guidance as to why it is not working for me?

Thanks!

Solution 1:

The <If> directive is only available in Apache 2.4+ and not 2.2 or earlier.

http://httpd.apache.org/docs/2.4/mod/core.html#if

Documentation not present in 2.2:

http://httpd.apache.org/docs/2.2/mod/core.html#if

Solution 2:

<If> is only available in Apache 2.4+, so firstly make sure that you have that version.

Examples

# Compare the host name to example.com and redirect to www.example.com if it matches
<If "%{HTTP_HOST} == 'example.com'">
  Redirect permanent "/" "http://www.example.com/"
</If>

<If "%{HTTP_HOST} =~ /regex/">
  SecFilterEngine Off
  SecFilterScanPOST Off
</If>

<If "%{REQUEST_URI} =~ m#/regex/including/slashes/#">
  SecFilterEngine Off
  SecFilterScanPOST Off
</If>

Alternatives to <If>

There are a few other solutions for doing conditional statements in Apache 2.2 if you're still stuck with that.

• You can set environment variables via:

  • Apache configuration
  • SetEnvIf
  • mod_rewrite's RewriteMatch

• Then you can perform conditional statements using

  <IfDefine MyEnvironmentVar>
     ...
  </IfDefine>
  

Example:

# Set environment variable if we're on staging site
SetEnvIf Host staging ROBOTS_NOINDEX

# Set environment variable if we're within a specific folder
SetEnvIf Request_URI ^/app/webroot/files/ ROBOTS_NOINDEX

# Send custom header if environment variable is set
Header set X-Robots-Tag "noindex" ENV=ROBOTS_NOINDEX