Reverse proxy configurations

Reverse Proxy Configurations

1. Simple without subdirectory
2. Simple with COPS accessible in "subdirectory"
3. Complex with multiple entrypoints
4. Debugging proxy configurations

Simple without subdirectory

flowchart LR
  client((Internet))
  proxy[Reverse Proxy\nhttps://cops.site.com/]
  cops[COPS\nhttp://127.0.0.1:8080/]
  client --> proxy --> cops

No change needed in config_local.php

If you want to enforce going via reverse proxy, specify cops_full_url in config_local.php:

// specify with full host url
$config['cops_full_url'] = 'https://cops.site.com/';

Simple with COPS accessible in "subdirectory"

flowchart LR
  client((Internet))
  proxy[Reverse Proxy\nhttps://www.site.com/cops/]
  cops[COPS\nhttp://127.0.0.1:8080/]
  client --> proxy --> cops

Specify cops_full_url in config_local.php:

// specify proxy prefix
$config['cops_full_url'] = '/cops/';
// or with full host url
//$config['cops_full_url'] = 'https://www.site.com/cops/';

Complex with multiple entrypoints

flowchart LR
  client((Internet))
  proxy[Reverse Proxy\nhttps://www.site.com/books/]
  cops[COPS\nhttp://172.18.0.2/]
  docker[Docker\nhttp://172.17.0.1/cops/]
  internal((Internal))
  direct((Direct))
  client --> proxy --> docker --> cops
  internal --> docker
  direct --> cops

a. Specify cops_trusted_proxies and cops_trusted_headers in config_local.php:

// specify trusted proxies (add as needed)
$config['cops_trusted_proxies'] = '172.18.0.1';
// specify trusted headers (adapt based on proxy configuration)
$config['cops_trusted_headers'] = ['x-forwarded-host', 'x-forwarded-proto', 'x-forwarded-prefix'];

See https://symfony.com/doc/current/deployment/proxies.html for more information

b. Or add some logic in config_local.php to adapt cops_full_url based on server request:

if ($_SERVER['REMOTE_ADDR'] === '172.18.0.1') {
    $via = $_SERVER['HTTP_X_FORWARDED_HOST'] ?? '';
    if ($via === 'www.site.com') {
        $config['cops_full_url'] = 'https://www.site.com/books/';
    } elseif ($via === '172.17.0.1') {
        $config['cops_full_url'] = 'http://172.17.0.1/cops/';
    }
}

Debugging proxy configurations

If you're not quite sure the reverse proxy configurations you made are doing what they're supposed to, have a look at the /checkconfig.php page, especially the section "Check if the base URL looks OK".

It will show you the base URL as seen by COPS locally, any cops_full_url you defined in config_local.php or the cops_trusted_proxies and cops_trusted_headers and their respective values that COPS received for that request