IBM® Rational® Publishing Engine web services provides a remote engine, instead of the
local engine that is used by a default IBM Rational Publishing Engine installation. The Launcher and Document Studio connect
to a remote engine and transfer the publishing process to a more powerful
machine. IBM Rational Publishing Engine web services are optional and you can install them based
on your requirement.
IBM Rational Publishing Engine web services provides a server-side facility to relocate
publishing operations, which can be resource intensive and time consuming,
to a high-performance system. You can manually install Rational Publishing
Engine web services. These web services generate documents on the
server, thereby offsetting the workload on the client. To deploy Rational
Publishing Engine web services, one of the following application servers
is required:
- Apache Tomcat 6.0.18
- WAS 6.1 and WAS 7
The licenses can either be floating user-based licenses
or authorized user-based licenses. Rational Publishing Engine web services can consume only floating licenses. If only authorized user-based licenses are purchased, Rational Publishing Engine web services cannot use them, and document generation
fails.
Rational Publishing Engine does the following:
- Provides request queueing to alleviate the resource strain on
the server. Based on 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 prepares an archive
containing the required artifacts such as one document specification,
one or more templates, and one or more stylesheet files. These files
are unpacked on the server and used as required.
- Packs all the output files in a single archive. Unlike when using
a local engine, a remote publishing process always returns a single
output archive, avoiding the need to download multiple files.
- Does not upload data. The data used for configuring the document
specification must be available in the server context.
- Downloads results.
- Provides load balancing to reduce the workload directed to a single
web server instance by providing a larger set of web service instances
to publish documents. The load balancer redirects the request to one
or more web service instances. If there are a large number of requests
to a particular web service that cannot cope with these requests,
you adopt the load balancing feature. Earlier, the only way to publish
documents using IBM Rational Publishing Engine web services was to provide the URL of the Rational Publishing Engine web services WSDL file in the Preferences window. To make use of load-balanced web services, you need to configure
the Rational Publishing Engine client with the gateway entry (which is a new URL). You
can then publish documents using the load balancer or using the existing
web service instance. The server that provides the load balancing
returns a URL with the address of the web service in either the first
or second instance of the Rational Publishing Engine web services. When the Rational Publishing Engine client sends the request to this URL, the requests goes
through the load balancer and the client receives the address of the
web service node that the load balancer has assigned. All further
communication for that document generation session occurs directly
with the assigned web services.
This new URL, http://localhost/rpe/wsgate, provides a gate to the Rational Publishing Engine web services and can be used outside the load balancer
environment. It redirects Rational Publishing Engine to the web services URL from the same server. The standard
web services can run in Websphere® Application Sever as well as Apache
Tomcat.
The configuration in the load balancer must use URLs
that are visible and can be resolved from all the client systems that
use Rational Publishing Engine. The local node must be visible and accessible from the
client.
- Provides mobility through 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 losing
connectivity to that process and download the results. On restoring
the connection you can still retrieve the generated documents. Earlier,
if the connection was lost, the document generation process was stopped,
and there was no way to obtain the document even when it was successfully
generated on the server.
- With the web services approach, various clients can be constructed,
for example, a Java™ client, and implemented in Rational Publishing Engine Launcher.
Restriction: The Rational Publishing Engine web services does not support thin clients. The client
must be AXIS2 compatible.