php-proxies-redirects

Maybe the simplest proxy and/or redirect engine (written in PHP)

Initial statement: I'm not a programmer. I'm a Systems Engineer.

Some point in time, I have been asked for help with some proxy and/or redirect engine without the ability to install any apps.

By the time I only had access to PHP and Apache to do so and additionally access to cron and to an existing lsyncd (and rsync) installation.

I made the decision to share this, maybe it is useful to someone else too and / or easily adapted to some other use cases.

So that's it: maybe an awful code but a working one.

Big help and initial inspiration from this proxy.php file from Ioannis Varouchakis at https://gist.github.com/iovar/9091078.

Tested with PHP 7.4 and 8.2.

Find the /path/to/backend and /path/to/frontend and change it to match your systems paths.

To Do:

• listen on Path rather than Domains only;
• logging;
• debugging.

Schematic

Backend

Back-office stuff.

There are some cron config and some writable directory permissions mandatory (for control files under _synchronize folder and for backup generation).

Maybe you want to restrict writable permissions for security reasons, so all files in _synchronize directory (!! EXCEPT action.sh and .htaccess !!), rules.ini and *.txt (backup) files under root.

"Important" files:

• index.php is a simple bootstrap back-office to manage the rules creation and edition;

• rules.ini is a PHP configuration file where all rules, proxy or redirect, are written. It will synchronized to one frontend by the action.sh;

• action.sh is a bash script to be called through cron to upload the rules.ini to one of the frontends. It requires the execute permission to the user where cron was configured;

• cron runs every minute in the attached file, you may customize it to your needs.

To Do:

• Delete rules

Frontend

The lsyncd is mandatory! The config is on the lsyncd.conf file.

"Important" files:

• .htaccess config all requests to go to index.php using the mod_rewrite Apache module;

• index.php is the one who will get all requests and make proxy or redirect stuff based on the requests received;

• lsyncd.conf is the lsyncd config file. It must be installed and configured in all frontends (3 frontends are considered: srv1.local, srv2.local and srv3.local. The attached config example is for srv1.local that synchronize to srv2 and srv3. Config for srv2.local would synchronize to srv1 and srv3 and, at last, config for srv3.local would synchronize to srv1 ans srv2 for full redundancy and synchronization).