Fixing SSL Redirect Loops and Mixed Content in PrestaShop 9 Behind a Reverse Proxy

PrestaShop 9 SSL Behind a Reverse Proxy: Solving Redirect Loops and Mixed Content

This insight summarizes a PrestaShop forum thread addressing a common issue: SSL redirect loops and mixed content errors when running PrestaShop 9 behind a reverse proxy like Traefik, Nginx, or Apache. The original poster, MigrationPro, provides a detailed solution to ensure PrestaShop correctly detects HTTPS connections when SSL is terminated at the proxy level.

The Problem: PrestaShop's Misinterpretation of Connection Protocol

When a reverse proxy handles SSL termination, PrestaShop's backend only sees HTTP traffic. This leads to PrestaShop not recognizing that the client connection is HTTPS, resulting in:

• Infinite redirect loops
• Mixed content warnings
• SSL showing as "disabled" in the Back Office

Root Cause: Missing HTTPS Detection

PrestaShop relies on the $_SERVER['HTTPS'] variable to determine if SSL is active. When behind a proxy, this variable is not set because the connection between the proxy and the PrestaShop server is unencrypted.

The Solution: A Four-Step Approach

The provided solution involves four key steps:

Step 1: Configure Your Reverse Proxy to Forward Headers

Ensure your reverse proxy forwards the X-Forwarded-Proto, X-Forwarded-For, and Host headers. Traefik typically does this automatically. For Nginx, add the following to your server configuration:

proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $host;

Step 2: Tell PrestaShop to Trust the Proxy Header

Add the following code snippet near the top of your config/defines.inc.php file:

if (isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https') {
    $_SERVER['HTTPS'] = 'on';
}

This code checks for the X-Forwarded-Proto header and sets the $_SERVER['HTTPS'] variable accordingly.

Step 3: Enable SSL in PrestaShop

Enable SSL within PrestaShop using one of the following methods:

• Option A (Console - Recommended for PS9):
  

  php bin/console prestashop:config set PS_SSL_ENABLED --value 1
  php bin/console prestashop:config set PS_SSL_ENABLED_EVERYWHERE --value 1

• Option B (Back Office): Navigate to Shop Parameters > General > Enable SSL = Yes, Enable SSL on all pages = Yes.
• Option C (SQL - if locked out):
  

  UPDATE ps_configuration SET value = '1' WHERE name = 'PS_SSL_ENABLED';
  UPDATE ps_configuration SET value = '1' WHERE name = 'PS_SSL_ENABLED_EVERYWHERE';

  Remember to replace ps_ with your actual table prefix if different.

Step 4: Verify Shop URL Settings

In Shop Parameters > Traffic & SEO > Shop URL, ensure both "Shop domain" and "SSL domain" are set to your public domain (without the https:// prefix).

Important Considerations

• defines.inc.php is generally more upgrade-safe than settings.inc.php, but it's still wise to check it after PrestaShop updates.
• Payment modules (like PayPal and Stripe) often check the PS_SSL_ENABLED setting in the database independently. Therefore, Step 3 is crucial even if HTTPS appears to be working after Step 2.
• Avoid modifying classes/Link.php directly, as changes will be overwritten during updates.
• Traefik automatically forwards the X-Forwarded-Proto header, while Nginx, Apache, and Caddy require explicit configuration.