How can I use SetEnvIf based on matches in the query string?

Question

The URL I'm using is, let's say, example.com/subdir/index.php?foo=bar

index.php contains this: <?php echo getenv("testenvvar"); ?>

I'm setting an enviroment variable in .htaccess like so:

SetEnvIf Request_URI (index) TestEnv=Worked

This prints "Worked".

If I change it to SetEnvIf Request_URI (bar) TestEnv=Worked, it does not.

How can I do this?

You are trying to access a string from the query arguments, that won't work. The query part simply is _not_ part of the `RequestURI`! This is clearly stated in the documentation: http://httpd.apache.org/docs/current/mod/mod_setenvif.html#setenvif That documenation actually points out specifically, where you can find an answer to your question :-) — arkascha, Jul 10 '15 at 14:06
I'd read that documentation, but it conflicted with my testing. In any case, it didn't yield me the answer. Apparently I should use RewriteCond, but I don't see how. — Duncan Marshall, Jul 10 '15 at 14:14
See here: http://stackoverflow.com/questions/19362746/rewritecond-with-setenv which refers to there: https://turboflash.wordpress.com/2010/05/27/apache-environment-variables-visibility-with-setenv-setenvif-and-rewriterule-directives/ — arkascha, Jul 10 '15 at 14:23

score 8 · Answer 1 · answered Jul 14 '20 at 21:23

8

Another option would be SetEnvIfExpr:

SetEnvIfExpr "%{QUERY_STRING} =~ /bar/" TestEnv=Worked

answered Jul 14 '20 at 21:23

Kevinoid

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score 4 · Accepted Answer · answered Jul 10 '15 at 18:05

4

To match query string you will need mod_rewrite rules instead of mod_setenv.

Place this code in root .htaccess:

RewriteEngine On

RewriteCond %{QUERY_STRING} bar [NC]
RewriteRule ^ - [E=TestEnv:Worked]

answered Jul 10 '15 at 18:05

anubhava

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it would be nice if you explained what is going on. [NC] means case insensitive, ^ - means don't change the url, just set and environment variable, – santiago arizti Jul 07 '17 at 23:23
`NC` is for ignore case match. It will match bar, Bar, BAR , baR etc in above example. – anubhava Jul 08 '17 at 06:16

score 2 · Answer 3 · answered Feb 19 '20 at 16:27

Let me explain more detailed how I applied it.

Assume we want to add a X-Robots-Tag header when the following URL is being requested: https://example.com/?whatever=true

This can be achieved by adding the following rules to the .htaccess file:

RewriteEngine On
RewriteCond %{QUERY_STRING} /?whatever=true$ [NC]
RewriteRule ^ - [E=NOINDEXFOLLOW:true]
Header set X-Robots-Tag "noindex, follow" env=NOINDEXFOLLOW

score 0 · Answer 4 · answered Aug 02 '21 at 04:08

0

Using SetEnvIfExpr and REDIRECT_NOINDEXFOLLOW works for me.

RewriteEngine On
SetEnvIfExpr "%{QUERY_STRING} =~ /bar/" NOINDEXFOLLOW
Header set X-Robots-Tag "noindex, follow" env=REDIRECT_NOINDEXFOLLOW

answered Aug 02 '21 at 04:08

Mau

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How can I use SetEnvIf based on matches in the query string?

4 Answers4