Conditionally set an Apache environment variable

Question

I would like to conditionally set the value of an Apache2 environment variable and assign a default value if one of the conditions is not met. This example if a simplification of what I'm trying to do but, in effect, if the subdomain portion of the host name is hr, finance or marketing I want to set an environment var named REQUEST_TYPE to 2, 3 or 4 respectively. Otherwise it should be 1. I tried the following configuration in httpd.conf:

<VirtualHost *:80> ServerName foo.com ServerAlias *.foo.com DocumentRoot /var/www/html SetEnv REQUEST_TYPE 1 SetEnvIfNoCase Host ^hr\. REQUEST_TYPE=2 SetEnvIfNoCase Host ^finance\. REQUEST_TYPE=3 SetEnvIfNoCase Host ^marketing\. REQUEST_TYPE=4 </VirtualHost> 

However, the variable is always assigned a value of 1. The only way I have so far been able get it to work is to replace: SetEnv REQUEST_TYPE 1 with a regular expression containing a negative lookahead: SetEnvIfNoCase Host ^(?!hr.|finance.|marketing.) REQUEST_TYPE=1

Is there a better way to assign the default value of 1? As I add more subdomain conditions, or if I allow another request attribute to affect the REQUEST_TYPE (e.g. if Remote_Addr = 192.168.1.[100-150] then REQUEST_TYPE = 5), the regular expression with the negative lookahead could get ugly and hard to manage.

Answer 1

So it appears it isn't possible to reassign an environment variable. But you can test if the variable is set, if not, set it to the default value.

SetEnvIfNoCase Host ^hr\. REQUEST_TYPE=2 SetEnvIfNoCase Host ^finance\. REQUEST_TYPE=3 SetEnvIfNoCase Host ^marketing\. REQUEST_TYPE=4 SetEnvIf REQUEST_TYPE ^$ REQUEST_TYPE=1