This guide explains the principle of URL rewriting (URL Rewriting), an essential technique for SEO and user experience.

Preamble

• Aesthetics and Clarity: transforms a complex URL (index.php?id=123) into a readable URL (/post-title/).
• Referencing (SEO): search engines prioritize URLs containing keywords over technical parameters.
• Security: hides the internal structure of your site and the technologies used (such as .php extensions).

URL rewriting example

Consider the URL: article.php?id=25&cat=4. The goal is for it to appear as: /article/25/4/. Here is how to configure your .htaccess file:

# Désactive l'affichage des répertoires et suit les liens symboliques
Options -Indexes +SymLinksIfOwnerMatch
# Active le moteur de réécriture
RewriteEngine on
# Définit la base de réécriture si votre site est dans un sous-dossier (ex: /admin/)
# RewriteBase /admin/
# Règle de réécriture
RewriteRule ^article/([0-9]+)/([0-9]+)/?$ article.php?id=$1&cat=$2 [L,QSA]

• [L] (Last): indicates that this is the last rule to apply if the condition is met.
• [QSA] (Query String Append): allows other potential parameters to be preserved at the end of the URL.

Important: implementing these rules does not automatically update your links; you must manually update the internal links in your HTML code or database to use the new format.

Redirect to a main domain (SEO)

To avoid duplicate content, it is imperative to redirect your secondary domains to your main domain in HTTPS.

RewriteEngine On
RewriteCond %{HTTP_HOST} ^domaine-secondaire.xyz [NC,OR]
RewriteCond %{HTTP_HOST} ^www.domaine-secondaire.xyz [NC]
RewriteRule ^(.*)$ https://www.mon-domaine-principal.com/$1 [R=301,L]

The R=301 header tells search engines that the redirect is permanent, thus transferring the SEO "power" to the correct domain.