Concatenate two strings in apache config

Question

In an apache config file how can i concatenate two strings?

For example:

"hello" + "world"
// "helloworld"

Why?

One might want to do this to handle large Headers such as a Content-Security-Policy below is an example of my CSP. You can see it is nicely formatted for maintainability but when being sent in the Headers it has unwanted whitespace.

Header set Content-Security-Policy "\
;default-src\
    'self'\
;child-src\
    'self'\
;connect-src\
    'self'\
;font-src\
    'self'\
    https://*.gstatic.com\
;form-action\
    'self';\
;frame-ancestors\
    'self'\
;frame-src\
    'self'\
;img-src\
    'self'\
    https://www.google.com/s2/favicons\
    https://www.google-analytics.com\
    https://*.gstatic.com\
    https://*.googleapis.com\
;object-src\
    'none'\
;script-src\
    'self'\
    'unsafe-eval'\
    https://www.google-analytics.com\
    https://*.googleapis.com\
;style-src\
    'self'\
    'unsafe-inline'\
    https://*.googleapis.com\
;\
"

@madebydavid its more of a syntax question, but im my case im setting a very large header (CSP) — Blowsie, Jul 31 '18 at 10:53
thanks for the syntax ;-) prefixing with `;` and the extra line-breaks +1 — Julien, Feb 01 '21 at 16:20

score 3 · Answer 1 · answered Jul 31 '18 at 10:31

3

I think you can declare variable like this : https://stackoverflow.com/a/15731921/6663198
Then, you can easily concatenate your variables

answered Jul 31 '18 at 10:31

Flyzzx

458
5
13

Thanks for your answer, however it doesn't really directly concatenate strings. I've updated my question to give some context. – Blowsie Aug 08 '18 at 07:36

score 0 · Answer 2 · edited Aug 01 '18 at 12:36

0

OIDCScope "profile email openid offline_access"
OIDCRemoteUserClaim  sub

<Location "/app2">
    AuthType openid-connect
    Require valid-user
    ProxyPass   "http://192.168.10.237/myapp"
    ProxyPassReverse  "http://192.168.10.237/myapp"

    RewriteEngine On
    RewriteRule .* - [E=PROXY_USER:%{LA-U:REMOTE_USER}] 
    RequestHeader set REMOTE_USER  %{PROXY_USER}e
</Location>

</VirtualHost>

edited Aug 01 '18 at 12:36

Nic3500

8,144
10
29
40

answered Jul 31 '18 at 10:31

Nitish

21
2

2

Thanks and welcome to SO, could you care to elaborate on how this answers the question? – Blowsie Jul 31 '18 at 10:58

score 0 · Answer 3 · answered Aug 06 '18 at 19:25

My best guess is to use either setenv or define directives to declare and define values and then simply refer it using ${VAR} syntax as noted here.

In principle, the below should work.

$httpd -DTestCaseOne

...

<IfDefine TestCaseOne>
  Define dir_name_one media
  Define dir_name_two images
</IfDefine>

...

Include "/etc/httpd/sites/${dir_name_one}-${dir_name_two}/env.conf"

The server version for above references is - Apache 2.4

score 0 · Answer 4 · answered Aug 07 '18 at 09:54

0

You can try like this:

set $text = 'text';  
set $additional "${text}additional";

answered Aug 07 '18 at 09:54

bitsobits

104
11

Thanks for your answer, however it doesn't really directly concatenate strings. I've updated my question to give some context. – Blowsie Aug 08 '18 at 07:36

score 0 · Answer 5 · answered Feb 01 '21 at 16:18

So far the best I managed is to post-edit* the Header

Note the extra space before the \ new-line char

Header set Content-Security-Policy "\
;default-src \
    'self' \
;child-src \
    'self' \
;connect-src \
    'self' \
"

# Remove unwanted whitespaces
Header edit* Content-Security-Policy "\s\s\s\s" ""

not 100% great, a bit expensive and could back-fire a bit, but well this is a way to do it

Concatenate two strings in apache config

5 Answers5