Important concepts before configuring your project's Dispatcher

In the context of Adobe Experience Manager and Dispatcher, the conf.d and conf.dispatcher.d directories play different roles in configuring and customizing Dispatcher.

In the following repository, I generated an AEM archetype and defined some dispatcher configs: https://github.com/JenniferSantoss/aem-sample-project/tree/feature/dispatcher

conf.d:

• In the conf.d directory, configuration files are typically placed that define global and general settings for the Dispatcher.
• Check here: https://github.com/JenniferSantoss/aem-sample-project/tree/feature/dispatcher/sampleproject-dispatcher/src/conf.d

conf.d/available_vhosts/default.vhost:

• The available_vhosts directory is where *.vhost files are stored, and the enabled_vhosts directory is where you enable Virtual Hosts by symlinking a file in available_vhosts to the enabled_vhosts directory.
• A vhost file is a configuration file used by web servers, such as Apache HTTP Server, to configure virtual host settings.
• A virtual host is a configuration that allows a single web server to host multiple different websites or domains on a single physical server.
• The vhost file contains configuration directives that specify how the web server should respond to requests for a given hostname or IP address. These directives include information such as the website's root directory, log file name, security settings, reverse proxy settings, and more.
• Each virtual host can have its own vhost file, which allows different websites hosted on the same server to have specific configurations that are isolated from each other.
• A ServerAlias is a configuration directive used in web servers, such as the Apache HTTP Server, to specify additional host names that should be associated with a specific virtual host. This directive is used to allow a single virtual host to respond to requests made by multiple host names.
• Besides just having the default.vhost file with some default configuration, we can create a project specification vhost file with specific configurations. Check here: https://github.com/JenniferSantoss/aem-sample-project/blob/feature/dispatcher/sampleproject-dispatcher/src/conf.d/available_vhosts/sampleproject.vhost

conf.d/rewrites/rewrite.rules

• The rewrite.rules file is included in the conf.d folder and contains a set of rewrite rules for mod_rewrite.
• URL rewriting is a powerful technique used to manipulate HTTP request URLs before they are processed by the web server. It allows you to dynamically modify incoming or outgoing URLs, redirect directives to other locations, add or remove query parameters, etc.
• Besides just having the rewrite.rules file with some default configuration, we can create a project specification rules file with specific configurations. Check here: https://github.com/JenniferSantoss/aem-sample-project/blob/feature/dispatcher/sampleproject-dispatcher/src/conf.d/rewrites/sampleproject_rewrite.rules

conf.d/variables/custom.vars

• The custom.vars file is included in the conf.d files and you can place your Apache variables there.
• Variables can be used in a variety of contexts within the Apache server configuration. They can represent values that are used in multiple parts of the configuration and can be defined once and reused in multiple places.
• Here are some custom vars that I created for my sample project (not real - just an example): https://github.com/JenniferSantoss/aem-sample-project/blob/feature/dispatcher/sampleproject-dispatcher/src/conf.d/variables/custom.vars

conf.dispatcher.d:

• The conf.dispatcher.d directory is used to store site or application specific configuration fragments.
• It allows you to break your configuration into smaller, more manageable chunks, which can be useful in environments where multiple teams or sites share the same Dispatcher server.
• Each configuration file placed in this directory is included in the overall Dispatcher configuration at runtime.
• This allows you to customize the configuration for specific sites or for specific functionality without having to modify the global Dispatcher configuration.
• The conf.dispatcher.d directory contains site or application specific configuration files, such as dispatcher.any, farm.any, cache.any, filter.any, and others.
• Check here: https://github.com/JenniferSantoss/aem-sample-project/tree/feature/dispatcher/sampleproject-dispatcher/src/conf.dispatcher.d

conf.dispatcher.d/available_farms/default.farm:

• The *.farm files are included in the conf.dispatcher.d/dispatcher.any file. These farm.any files exist to control the behavior of the module for each rendering or site type. The files are created in the available_farms directory and enabled with a symbolic link in the enabled_farms directory.
• The available_farms folder within the conf.dispatcher.d directory in the context of AEM Dispatcher is used to store configuration files that define the so called "farms" available to Dispatcher. A farm in Dispatcher is a configuration that defines a set of rules for directing HTTP requests to specific backend servers.
• These configuration files contain information about the backend servers, such as their IP addresses, ports, load balancing settings, security settings, etc. Each configuration file in the available_farms folder usually defines a specific farm.
• These files are called available because Dispatcher does not necessarily use all of the farms defined in these files. Instead, the Dispatcher chooses which farm to use based on rules defined in its main configuration file, usually called dispatcher.any.
• In this file, I included some custom configs that I created for my specific sample project example, such as clientheaders and virtualhosts: https://github.com/JenniferSantoss/aem-sample-project/blob/feature/dispatcher/sampleproject-dispatcher/src/conf.dispatcher.d/available_farms/sampleproject.farm

conf.dispatcher.d/filters/filters.any

• The filters.any file within the conf.dispatcher.d/filters directory in the context of AEM Dispatcher is used to define the filtering settings that the Dispatcher will apply to the HTTP requests it receives. These filter settings help you control which requests are allowed or blocked, as well as make modifications to the requests or responses as needed.
• The best practice is to deny everything on filters and then allow only what is necessary for your project.

conf.dispatcher.d/virtualhosts/virtualhosts.any

• The virtualhosts.any file is included in the conf.dispatcher.d/virtualhosts files and contains a list of hostnames or URI paths to be matched by blob matching to determine which backend to use to serve that request.
• The virtualhosts.any file allows for flexible and granular configuration of virtual hosts in the Dispatcher, which is crucial for effectively routing web traffic to the AEM environment and ensuring proper website functionality and security.
• In this file I used the variables I created for my Sample Project Publish Local, Dev, Stage, Prod environments:? https://github.com/JenniferSantoss/aem-sample-project/blob/feature/dispatcher/sampleproject-dispatcher/src/conf.dispatcher.d/virtualhosts/sampleproject_virtualhosts.any
• This variables were defined on the file: https://github.com/JenniferSantoss/aem-sample-project/blob/feature/dispatcher/sampleproject-dispatcher/src/conf.d/variables/custom.vars

conf.dispatcher.d/cache/rules.any

• The rules.any file inside the conf.dispatcher.d/cache directory is used to configure caching rules in Dispatcher, controlling which HTTP requests are cached, for how long, and how the cache should be managed and invalidated. This plays a key role in optimizing website performance and efficiently delivering content to end users.

conf.dispatcher.d/clientheaders/clientheaders.any

• The clientheaders.any file is used to define settings related to the HTTP headers sent by clients to the Dispatcher, allowing you to control, filter, and manipulate these headers as needed to ensure proper application security, performance, and functionality.

conf.dispatcher.d/dispatcher.any

• The dispatcher.any file inside the conf.dispatcher.d directory in AEM Dispatcher is the main configuration file for Dispatcher. It plays a crucial role in the configuration and functioning of Dispatcher, allowing you to control how HTTP requests are routed, managed, and delivered to the origin server.?
• It's basically a file provided by the runtime environment and only included for illustration purposes and we should not edit this file.