Troubleshooting Dispatcher Problems

NOTE

Dispatcher versions are independent of AEM, however the Dispatcher documentation is embedded in the AEM documentation. Always use the Dispatcher documentation that is embedded in the documentation for the latest version of AEM.

You may have been redirected to this page if you followed a link to the Dispatcher documentation that is embedded in the documentation for a previous version of AEM.

NOTE

Check the Dispatcher Knowledge Base, Troubleshooting Dispatcher Flushing Issues and the Dispatcher Top Issues FAQ for further information.

Check the Basic Configuration

As always the first steps are to check the basics:

Confirm Basic Operation
Check all log files for your web server and Dispatcher. If necessary, increase the loglevel used for the Dispatcher logging.
Check your configuration:
- Do you have multiple Dispatchers?
  - Have you determined which Dispatcher is handling the website / page you are investigating?
- Have you implemented filters?
  - Are these filters impacting the matter that you are investigating?

IIS Diagnostic Tools

IIS provides various trace tools, dependent on the actual version:

IIS 6 - IIS diagnostic tools can be downloaded and configured
IIS 7 - tracing is fully integrated

These tools can help you monitor activity.

IIS and 404 Not Found

When using IIS, you might experience 404 Not Found being returned in various scenarios. If so, see the following Knowledge Base articles.

Also check that the Dispatcher cache root and the IIS document root are set to the same directory.

Problems Deleting Workflow Models

Symptoms

Problems trying to delete workflow models when accessing an AEM author instance through the Dispatcher.

Steps to reproduce:

Log in to your author instance (confirm that requests are being routed through the Dispatcher).
Create a workflow; for example, with the Title set to workflowToDelete.
Confirm that the workflow was successfully created.
Select and right-click the workflow, then click Delete.
Click Yes to confirm.
An error message box appears that shows the following:
" ERROR 'Could not delete workflow model!!".

Resolution

Add the following headers to the /clientheaders section of your dispatcher.any file:

x-http-method-override
x-requested-with

{
{
/clientheaders
{
...
"x-http-method-override"
"x-requested-with"
}

Interference with mod_dir (Apache)

This process describes how the Dispatcher interacts with mod_dir inside the Apache webserver, as it can lead to various, potentially unexpected effects:

Apache 1.3

In Apache 1.3, mod_dir handles every request where the URL maps to a directory in the file system.

It will either:

redirect the request to an existing index.html file
generate a directory listing

When the Dispatcher is enabled, it processes such requests by registering itself as a handler for the content type httpd/unix-directory.

Apache 2.x

In Apache 2.x, things are different. A module can handle different stages of the request, such as URL fixup. The mod_dir handles this stage by redirecting a request (when the URL maps to a directory) to the URL with a / appended.

Dispatcher does not intercept the mod_dir fixup, but completely handles the request to the redirected URL (that is, with / appended). This process might pose a problem if the remote server (for example, AEM) handles requests to /a_path differently to requests to /a_path/ (when /a_path maps to an existing directory).

If this situation happens, you must either:

disable mod_dir for the Directory or Location subtree handled by the Dispatcher
use DirectorySlash Off to configure mod_dir not to append /