URL Rewrite in Web Development

URL rewriting is a technique used in web development to modify the URL structure that the server receives. Unlike redirection, which sends a new URL back to the browser for another request, URL rewriting reconstructs the URL for the script on the server side.

Redirection can be categorized into two common types: 301 redirection, which is permanent, and 302 redirection, which is temporary. The type of redirection used can impact how search engines update their databases.

Benefits of URL Rewriting

• URL rewriting enables the separation of the URL from the actual resource, making it easier to locate resources on a website.
• For instance, a user-friendly URL like www.abc.com/aboutus can be internally rewritten to www.abc.com/page.php=1, improving user experience and SEO.

URL Rewriting Modules

Various web servers utilize specific modules for URL rewriting:

• Apache: Apache web server employs the mod_rewrite module for URL rewriting.
• Windows IIS: Windows IIS server uses the ISAPI Rewrite module, often requiring a paid license for advanced features.

Sample URL Rewrite Configuration

RewriteEngine On
RewriteBase /base
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{QUERY_STRING} !^id=0$
RewriteRule ^products/(.+)$ ^products.php?id=$1$ [L]
    

Understanding Rewrite Rules

• RewriteBase: It assists in stripping the base and applying regex to the remaining URL, ensuring the .htaccess file remains at the root directory.
• RewriteCond: This directive matches the test string against a pattern, enabling conditional rewriting based on factors like query strings, file existence, and HTTP headers.
• RewriteRule: Defines the actual rewriting logic by rewriting the URL based on defined patterns and conditions. It includes modifiers for permanent or temporary redirections, case insensitivity, and rule termination.