IBM® Rational® Publishing Engine web service provides a remote engine, instead of the local
engine used by a default Rational Publishing Engine installation. The Launcher and Document Studio connects
to a remote engine and transfers the publishing process to a more
powerful machine. Rational Publishing Engine Web Service are optional and you may install them based
on your requirement.
Rational Publishing Engine web service provides server-side facility to relocate
potentially resource and time consuming publishing operation to a
high-performance machine. Rational Publishing Engine web service is available as part of the installation.
You can manually install Rational Publishing Engine web service. Rational Publishing Engine web service performs generates documents
on the server machine thereby offsetting workload on the client machine.
As a requirement to deploy Rational Publishing Engine web service, the following application servers
are required:
- Apache Tomcat 6.0.18
- WAS 6.1
- Any Axis compatible application server
Rational Publishing Engine however it does the following:
- Provides request queueing to alleviate the resource strain on
the server. Based on the server settings, the server can process a
certain number of publishing requests simultaneously. Further requests
are moved to a queue until a slot is made free by a process that has
ended.
- Uploads the required artifacts. The launcher will prepare an archive
containing required artifacts: one document specification, one or
more templates, one or more stylesheet files. These files are unpacked
on the server and consumed as required.
- All the output files are packed in a single archive. Unlike when
using a local engine, a remote publishing process will always return
a single output archive. This avoids the need to download multiple
files.
- Does not upload data. This means the data used for configuring
the document specification must be available in the server context.
- Downloads results.
- Provides the load balancing feature that reduces work load directed
to a single web server instance by providing a larger set of web
service instances to publish documents. The load balancer will redirect
the request to one or more web service instances. If there are a
large number of requests to a particular web service and if that web
service cannot cope with these requests, you adopt the load balancing
feature.
Earlier, the only way to publish documents using Rational Publishing Engine web service was through the Preferences option. Now, you can use a load balancing gateway entry (which is
a URL) to publish documents using the load balancer or using the existing
web service instance. The server which provides the load balancing
will return a URL that has the address of the web service either in
the first or second instance of the Rational Publishing Engine web service. When Rational Publishing Engine client sends the request to this URL, the requests goes
through the load balancer. The load balancer dispatches the request
to one of the available server. You can configure the Rational Publishing Engine launcher to use the load balancer directly.
This
new URL, http://localhost/rpe/wsgate which
provides a gate to the Rational Publishing Engine web service can also be used outside the load balancer
environment. It will redirect the Rational Publishing Engine to the web service URL from the same server. The standard
web service can run in Websphere as well as Apache
Note: The configuration
in the load balancer must use URLs that are visible and can be resolved
from all the client machines that use the Rational Publishing Engine. The local node, be visible and accessible from the Rational Publishing Engine client.
- Provides mobility via connection recovery. For a long remote publishing
process, you can disconnect your laptop from the Rational Publishing Engine web service processes and reconnect later without loosing
the connectivity to that process and download the results. On restoring
the connection you can still retrieve the generated documents. Earlier,
if the connection disconnected, the document generation process aborts
and there was no way to obtain the document although the document
was successfully generated on the server.
- With the WS approach, various clients can be constructed, eg. Java client, implemented in Rational Publishing Engine Launcher.
Note: The Rational Publishing Engine Web Service does not support thin clients. The client
must be AXIS2 compatible.