Apache as Proxy replace the html code/tags/text

Question

I configured my Apache server as a proxy server. I added some filters to my proxy.conf file to change the text (HTML source code) of the websites.

Example code:

ExtFilterDefine foodo mode=output intype=text/html
cmd="/bin/sed -r 's/foo/newfoo/g'" 
SetOutputFilter foodo

I have enabled also every possible mods for that. (mod_proxy, mod_proxy_html, ...)

After I used also mod_sed to change some text but still I have no positive solution.

<Directory "/var/www/docs/sed"> 
    AddOutputFilter Sed html 
    OutputSed "s/monday/MON/g" 
    OutputSed "s/sunday/SUN/g" 
</Directory>

Here is my proxy.conf:

ProxyRequests On
ProxyVia On
<Proxy *>
    Order deny,allow
    Deny from all
    Allow from all
</Proxy>

Do anyone have any idea for this problem?

Solution 1

You should be able to use mod_substitute. In your proxy config, add:

AddOutputFilterByType SUBSTITUTE text/html
Substitute "s/foo/bar/ni"

---

I got it working with the following config:

<VirtualHost *:80>
        ServerName su-test.int.mtak.nl

        ProxyRequests Off
        ProxyPreserveHost Off
        ProxyPass       / http://mtak.nl/
        ProxyPassReverse / http://mtak.nl/
        RequestHeader unset Accept-Encoding

        FilterDeclare CUSTOMFILTER
        FilterProvider CUSTOMFILTER SUBSTITUTE resp=Content-Type $*
        FilterProvider CUSTOMFILTER SUBSTITUTE resp=Content-Type $/html

        <Location />
                FilterChain CUSTOMFILTER
                Substitute "s|foo|bar|ni"
        </Location>

</VirtualHost>

The line RequestHeader unset Accept-Encoding is to make sure the webserver doesn't send a gzipped response, which Apache would be unable to substitute the contents of.

Solution 2

For Apache >= 2.4 the FilterProvider syntax was changed. I was able to get the following to work:

FilterProvider CUSTOMFILTER SUBSTITUTE "%{CONTENT_TYPE} =~ m|^text/html|"

Comments

[xmux]

Yep i tried that also today! sudo a2enmod substitute and then <Location /> AddOutputFilterByType SUBSTITUTE text/html Substitute s/foo/bar/ni </Location> and then i restarted my apache server! Then when i visited the website from the client side and look up the source code "foo" is still there.

[xmux]

And also my proxy.conf file looks like that: ProxyRequests On ProxyVia On <Proxy *> Order deny,allow Deny from all Allow from all </Proxy>

[mtak]

@xmux I've updated my post with a config that is tested and works for me.

[xmux]

Thanks! but then this one is the 000-default.conf file and i want still a proxy server actually. And i am using apache 2.4, does it make any difference?

[xmux]

You were totaly right about this "RequestHeader unset Accept-Encoding" after that i just updated my proxy.conf with <Location /> AddOutputFilterByType SUBSTITUTE text/html Substitute s/foo/bar/ni </Location> and it just worked! Thanks a lot! if you want, you can change the answer to a normal substitute example.

[Yash Agarwal]

Thank you so much for this answer. I had a feeling that gzip was causing the issue so I tried AddOutputFilterByType INFLATE to fix this. But although now response wasn't gzipped still substitute was not working. I tried you technique and it worked.

[cmcginty]

Getting an error on the first FilterProvider line: "FilterProvider takes three arguments, filter-name provider-name match-expression"