How to Configure Apache mod_rewrite

Apache mod_rewrite provides powerful URL transformation capabilities. Using proper flags ensures correct redirect behavior. This guide walks through the specific troubleshooting steps to diagnose and resolve mod_rewrite issues.

Before You Begin

Before you begin, be sure to have the following in place:

• A Linux server with the relevant software installed
• Access to the command line interface
• Appropriate permissions (root or sudo)

Quick Fix

Wrong

RewriteEngine On\nRewriteRule ^old$ /new [R]

Wrong: Rewrite without status code or last flag

Right

RewriteEngine On\nRewriteRule ^old$ /new [R=301,L]

Right: Rewrite with 301 permanent and L (last) flag

Output

Rewrite rule enabled:\n  Pattern: ^old$ → /new\n  Flags: R=301, L\n  Redirect: permanent

Prevention

To avoid future issues, follow these best practices:

• Enable RewriteEngine On before any rewrite rules
• Use [L] (last) flag to stop processing when a rule matches
• Set explicit redirect status: [R=301] for permanent, [R=302] for temporary
• Use [NC] for case-insensitive matching
• Test rules with RewriteLog or curl -I before deploying

DodaTech Tools

For further assistance with any of the above issues, consider using DodaTech consulting services or DodaTech tutorials for more in-depth guidance.

Common Mistakes with rewrite

1. Misunderstanding that String is [Char] with poor performance for large text operations
2. Using foldl instead of foldl' causing stack overflow on large lists
3. Forgetting deriving (Show, Eq) on custom data types needed for debugging

These mistakes appear frequently in real-world APACHE code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ