${tomcat_home} is the root directory of tomcat. Your Tomcat installation should have the following subdirectories:

• ${tomcat_home}\conf - Where you can place various configuration files
• ${tomcat_home}\webapps - Containing example applications
• ${tomcat_home}\bin - Where you place web server plugins

In all the examples in this document ${tomcat_home} will be c:\tomcat. A worker is defined to be a tomcat process that accepts work from the Sun ONE Web Server.

The NSAPI-Tomcat redirector was developed and tested on:

• WINNT 2000/XP/2003 (should be able to work with other service packs) and some Unixes
• Sun ONE Web Server 6.1
• Tomcat 4.1.x , Tomcat 5.0.x and Tomcat 5.5.x

The redirector uses ajp12 and ajp13 to send requests to the Tomcat containers. There is also an option to use Tomcat in process, more about the in-process mode can be found in the in process howto.

The ajp12 protocol is only available in Tomcat 3.2.x and 3.3.x.

The ajp12 has been deprecated with Tomcat 3.3.x and you should use instead ajp13 which is the only ajp protocol known by Tomcat 4.0.x, 4.1.x, 5.0.x, 5.5.x and 6.

Of course Tomcat 3.2.x and 3.3.x also support ajp13 protocol.

Others servlet engines such as jetty have support for ajp13 protocol

1. The NSAPI-Tomcat redirector is an Netscape service step plugin, Netscape load the redirector plugin and calls its service handler function for request that are assigned to the "servlet" configuration object.
2. For each in-coming request Netscape will execute the set of NameTrans directives that we added to obj.conf, the assign-name function will check if it's from parameter matches the request URL.
3. If a match is found, assign-name will assign the servlet object name to the request. This will cause Netscape to send the request to the servlet configuration object.
4. Netscape will execute our jk_service extension. The extension collects the request parameters and forwards them to the appropriate worker using the ajp13 protocol (the worker="defworker" parameter in jk_service inform it that the worker for this request is named defworker). the workers properties files, workers.properties, will indicate that defworker use ajp13 protocol.
5. The extension collects the response from the worker and returns it to the browser.

The examples context is useful for verifying your installation, but you will also need to add your own contexts. Adding a new context requires two operations:

• Adding the context to Tomcat (I am not going to talk about this).
• Assigning the NSAPI redirector to handle this context.

Assigning the NSAPI redirector to handle this context is simple, all you need to do is to edit obj.conf and add a NameTrans line that looks like:

After saving obj.conf restart Netscape and it will serve the new context.

Sometimes it is better to have Netscape serve the static pages (html, gif, jpeg etc.) even if these files are part of a context served by Tomcat. For example, consider the html and gif files in the examples context, there is no need to serve them from the Tomcat process, Netscape will suffice.

Making Netscape serve static files that are part of the Tomcat contexts requires the following:

• Configuring Netscape to know about the Tomcat contexts
• Make sure that the WEB-INF directory is protected from access.
• Configuring Netscape to assign the NSAPI redirector only specific requests that requires JSP/Servlet handling.

Adding a Tomcat context to Netscape requires the addition of a new Netscape virtual directory that covers the Tomcat context.

For example, adding a /example Netscape virtual directory that covers the c:\tomcat\webapps\examples directory.

To add a new virtual directory add the following line to your obj.conf:

WEB-INF protection requires some explanation; Each servlet application (context) has a special directory named WEB-INF, this directory contains sensitive configurations data and Java classes and must be kept hidden from web users. WEB-INF can be protected by adding the following line to the PathCheck section in the default configuration object:

Configuring Netscape to assign the NSAPI redirector only specific requests is somewhat harder, you will need to specify the exact URL-Path pattern(s) that you want Tomcat to handle (usually only JSP files and servlets).

This requires a change to NameTrans portion of obj.conf.

As you can see the second configuration is more explicit, it actually instructs Netscape to assign the redirector with only requests to resources under /examples/servlet/ and resources under /examples/ whose name ends with .jsp.

You can be even more explicit and provide lines such as:

Sometimes you want to serve different contexts with different Tomcat processes (for example to spread the load among different machines). To achieve such goal you will need to define several workers and assign each context with its own worker.

Defining workers is done in workers.properties, this file includes two types of entries:

The above examples defined two workers, now we can use these workers to serve two different contexts each with it's own worker. Submitting requests to different workers is accomplished by using multiple Service directives in the servlet configuration Object, each with a different path pattern parameter.

For example, if we want to submit the /examples context to the worker named worker1 and the /webpages context to the worker named worker2 we should use the following configuration:

More informations on using and configuring workers in the Workers HowTo and in the worker.properties configuration reference.