Testing Apache RewriteRule Locally Using Docker

Introduction Link to heading

Adobe Experience Manager (AEM) developers often face challenges when testing RewriteRule directives within the AEM Dispatcher setup. Setting up a local Dispatcher environment can be cumbersome and time-consuming. Fortunately, Docker provides an efficient solution to test these rewrite rules without needing a full Dispatcher setup. This guide will demonstrate how to leverage Docker to quickly and easily test Apache RewriteRule configurations. Whether you are an AEM developer or anyone looking to test RewriteRule locally, this blog will provide you with a straightforward, step-by-step approach.

Why Docker is a Game-Changer for AEM Developers Link to heading

Dispatcher-Free: No need to grapple with Dispatcher configuration for simple RewriteRule testing.
Rapid Iteration: Quickly experiment with different rule combinations without impacting your AEM instance.
Isolation: Your tests won’t interfere with your actual AEM development setup.

Step-by-Step Guide Link to heading

Create a Project Directory:
```
mkdir apache-redirect-test
cd apache-redirect-test
```
This dedicated directory will house our test configuration.
Extract Default Apache Configuration:
```
docker run --rm httpd:2.4 cat /usr/local/apache2/conf/httpd.conf > my-httpd.conf
```
We’re pulling the standard Apache configuration from the official Docker image to use as a starting point.
Activate mod_rewrite:
```
# Open my-httpd.conf and find this line:
# LoadModule rewrite_module modules/mod_rewrite.so
# Remove the leading # to uncomment it.
```
The mod_rewrite module is the engine behind Apache’s RewriteRule functionality. Search for the line containing LoadModule rewrite_module modules/mod_rewrite.so in my-httpd.conf and uncomment it by removing the #. This will enable the rewrite module in Apache.
Add Your AEM-Specific Rewrite Rules:
```
# Append your rules to the end of my-httpd.conf
RewriteEngine On
RewriteRule ^/content/mysite/(.*)$ /content/mysite/en/$1 [R=302,L]
```
This example rule redirects requests under /content/mysite to their English language equivalent. Tailor this to your AEM project’s structure.
Start the Dockerized Apache Server:
```
docker run --rm -p 8080:80 -v ./my-httpd.conf:/usr/local/apache2/conf/httpd.conf httpd:2.4
```
- --rm: Cleans up the container when you stop it.
- -p 8080:80: Maps local port 8080 to the container’s port 80, so you can access the server via http://localhost:8080.
- -v ...: Mounts your modified configuration file into the container.

Equivalent docker-compose.yml (Optional)

You might want to use a equivalent docker-compose.yml if that required:

---
services:
  web:
    image: httpd:latest
    ports:
      - "8080:80"
    volumes:
      - ./my-httpd.conf:/usr/local/apache2/conf/httpd.conf

Now, you can run docker compose up to run the container.

Test Your RewriteRules Link to heading

Open your browser and navigate to http://localhost:8080/content/mysite/somepage. If your rule is correct, you’ll be redirected to http://localhost:8080/content/mysite/en/somepage.

Tips for AEM Developers Link to heading

Mimic Dispatcher Rules: Replicate the logic of your production Dispatcher rules to ensure accurate testing.
Debugging: If your rules aren’t working, use the LogLevel directive in my-httpd.conf to get more verbose logs from Apache.
Advanced Scenarios: Consider using Docker Compose to create more complex environments that simulate AEM author and publish instances alongside your Apache server.

Conclusion Link to heading

By utilizing Docker, AEM developers can dramatically simplify the process of testing Apache RewriteRules. This method is efficient, focused, and avoids the overhead of setting up a full Dispatcher environment just for rule testing. Happy coding!