How to escape spaces in Apache SetEnvIf value

Question

I am trying to use SetEnvIf (Apache2, via a .htaccess file) to store an environment variable where the value to be assigned to the variable needs to contain spaces. For example, trying to set environment variable "AUTH_KEY" to have value "a b":

SetEnvIf Request_URI "^/example" AUTH_KEY="a\ b"

No matter what I do, I have not been able to escape the space in the value - the space acts as a delimiter between env vars to be created (in the above AUTH_KEY is created with value '"a\' and a second env var is created called 'b"'). I have tried single-quotes too with no luck.

How do I escape the space character?

This is a terrible shot in the dark and I don't even expect it to work. What happens if you URLencode the space? (i.e. use %25 in place of one) Yes, I know this isn't a URL and I don't expect it to be treated like one. — Andrew B, Apr 04 '13 at 22:05
Thanks Andrew, in the end I figured out how to add spaces without having to use escaping (it works for me at least). I found that placing the quotes around the key=value, rather than just the value was the way to go. — Alex B, Apr 05 '13 at 13:52

score 7 · Accepted Answer · answered Apr 05 '13 at 13:44

In the end I figured it out for myself…

SetEnvIf Request_URI "^/example" "AUTH_KEY=a b"

… which looks odd, but works. It correctly sets AUTH_KEY to value a b

Hopefully this might save someone else's time in the future.

The details:- I am not a C programmer, but bumbling around on Google I found mod_setenvif.c listed at http://www.bvbcode.com/code/s6148jvr-385031

A function is called on line 405 (ap_getword_conf, for which I found detail at http://docstore.mik.ua/orelly/apache_mod/155.htm) which seems to parse strings, delimited by whitespace (but optionally encapsulated in quotes and accepting the use of escape characters).

I noticed that this happened before the sub-string returned by the function above being split by the '=' character (line 411, by function ap_getword). Thus quotes around the key=value pair, rather than just the value.

score 0 · Answer 2 · answered Apr 04 '13 at 18:33

0

Try using instead SetEnvIf Request_URI "^/example" AUTH_KEY="a\sb". \s here represents the space.

answered Apr 04 '13 at 18:33

Meriadoc Brandybuck

1,330
9
11

1

Thanks, I tried that after you posted but still no luck (the variable value gets set as _"a\sb"_ (i.e. \s does not get replaced). – Alex B Apr 04 '13 at 19:06
1

Also worth noting is that the quote marks are included in the value - they seem to be part of the value itself. Thanks – Alex B Apr 04 '13 at 19:08
Try using a[\s]b. Looking forward to your results. – Meriadoc Brandybuck Apr 04 '13 at 19:21
Still no luck, `a[\s]b` is set as the value as-is. Thanks for the thought though. – Alex B Apr 04 '13 at 19:38

How to escape spaces in Apache SetEnvIf value

2 Answers2