IBM® Rational® Publishing Engine web
services provide a remote engine that can be used instead of a local Rational Publishing Engine engine.
The Launcher and Document Studio connect to the remote engine and
transfer the publishing process to another system. Rational Publishing Engine web
services are optional and you can install them based on your requirements.
Rational Publishing Engine web
services provides a server-side facility to relocate publishing operations,
which can sometimes be resource intensive and time consuming, to a
high-performance system. These web services generate documents on
the server, which offsets the workload on the client.
License requirements for web services
Rational Publishing Engine 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.
Web services capabilities
The web services
application can complete the following tasks:
- 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 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 style sheet 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 many 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 Rational Publishing Engine web
services was to provide the URL of the Rational Publishing Engine web
services WSDL file in the Preferences window.
To use load-balanced web services, you must configure the Rational Publishing Engine client
with the gateway entry, which is a 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 assigned. All further communication for that
document generation session occurs directly with the assigned web
services.
This 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 Server 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 computer 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.