How to inject HTML code into every delivered HTML page?

Question

I've got an Apache web server that delivers static HTML pages. For some reason I can't change the files themselves, but I still want to inject some HTML into every page that is being served.

Is this possible with mod_proxy? If not, could anyone recommend a software that provides such a feature?

EDIT: I have to insert some kind of banner ad (e.g. a javascript) and a tracking pixel.

Solution 1

You could do this: Work with mod_rewrite to change requests from

/some/static/page.html

to

/htmlinjector.php?url=/some/static/page.html

then use PHP (or whatever you find appropriate) to do the file-manipulation. Add an output cache to improve performance.

As an alternative, Apache Handlers sound helpful:

Modifying static content using a CGI script

The following directives will cause requests for files with the html extension to trigger the launch of the footer.pl CGI script.

Action add-footer /cgi-bin/footer.pl
AddHandler add-footer .html

Then the CGI script is responsible for sending the originally requested document (pointed to by the PATH_TRANSLATED environment variable) and making whatever modifications or additions are desired.

This is more or less what the mod_rewrite approach would do, only with less hackery.

Solution 2

I am not sure why this hasn't been mentioned in the list of answer. Sorry if it took me 2 years to see this question...

The easiest, most powerful way to do what you want to do what you want is using an Apache filter.

Just have:

ExtFilterDefine css_changer mode=output intype=text/html cmd="/some/php/script.php"
SetOutputFilter css_changer

A possible script:

#!/usr/bin/php
<?

#phpinfo(); // Uncomment to see ALL env variables
$host = $_ENV["HTTP_HOST"]; // www.site.com
$script_name = $_ENV["SCRIPT_NAME"]; // /theme/green/style.css
$pi = pathinfo($script_name);
$type = $pi['extension'];
#print "$host $script  $type";

$stdin = STDIN;

while($line = fgets($stdin)){
  $line = preg_replace('/a/', 'A', $line);

  fwrite(STDOUT, $line);
}
fclose(STDOUT);
?>

This will change all "a"s into "A"s .

Be sure to enable filter in your httpd.conf, like this:

LoadModule ext_filter_module libexec/apache2/mod_ext_filter.so

This question ranks really up in Google and there isn't much out there in terms of forums

Solution 3

Here is a tutorial on how to use mod_proxy_html to edit the links on a webpage ( the content). You might be able to apply this modify the html you want.

UPDATE: Are you sure you want to go this route? I think Apache is meant to serve content, not create it. This would probably go in the view part of a MVC framework. The reason I wouldn't recommend this is you are breaking the rule of modularity. Your web application will be intertwined with the application that server it, complicating future upgrades, moves, etc.

Solution 4

mod_sed is a good fit here. You can create an output filter that matches the closing head or body tag, for example, and insert your html before it.

Solution 5

I would prefer to do this with mod_rewrite and SSI.

First put the path into an environment variable

RewriteCond %{IS_SUBREQ} false
RewriteRule ^(/.*\.html) /page.shtml [E=filename:$1]

then process that in the shtml file

<!--#include virtual="$filename"-->

Parts of this solution are based on a stackoverflow question: https://stackoverflow.com/questions/40133/getting-apache-to-modify-static-webpages-on-the-fly/1196832 )

View more solutions

Comments

[Node]

Hm, if I get it right mod_proxy_html is not capable to add complete new code snipets?

[Kyle Brandt]

Not sure, now that you have added more, Commander Tomalak's answer sounds better. You are in the land of hackery I would say, creating web pages isn't really what Apache is for, it is for serving up content.

[Node]

I tought that there is maybe some kind of standalone proxy which could rewrite html pages. Something like MySQL Proxy for MySQL. Maybe Privoxy could do this.

[Tomalak]

@Kyle Brandt: LOL - I think the mention of the military rank officially makes you a trekkie. This made my day. :)

[Node]

Thx, I'll have a look, at the moment we tend to httpd.apache.org/docs/2.0/handler.html with a custom footer.pl

[Alex Lehmann]

My main reason to want to use shtml for this would be that calling an external CGI for each request might cause load problems.

[maestro416]

That's by far the best solution, i was able to find for a similar problem. Thanks very much for sharing!

[Asaf]

Can someone give an example of the mod_rewrite solution? (specifically the content of htmlinjector.php)

[Sridhar Sarnobat]

For those of you struggling with this - don't forget ScriptAlias and <Directory /some/static/>...</Directory>, <Directory /path/to/cgi-bin/> Options +ExecCGI</Directory>etc. I don't want to tamper with the user's answer but if you request, I will give more info.

[Gabriel Nwoffiah II]

@asdf Example: <?php ob_start(); include("/some/static/page.html"); $contents = ob_get_contents(); ob_end_clean(); echo str_replace('</head>', '<script async>Some script content goes here like adsense code</script></head>', $contents) ?> use $content to load the rest of the page content. you can save this file as htmlinjector.php or whatever and call it in your htaccess file like this: Options +FollowSymLinks RewriteEngine On RewriteCond %{REQUEST_FILENAME} /some/static/page.html RewriteRule ^(.*)$ /htmlinjector.php?url=/some/static/page.html

[Khom Nazid]

On a shared hosting server this may not be available. Anyway how would one find the closing body tag and insert a Google Analytics code just before it?