Overview

The Client Download Service enables you to build version-compatibility checks and automatic updates into client applications that use the Content Platform Engine APIs. A client can compare and report on the compatibility between its APIs and the API versions on the Content Platform Engine. If incompatibilities exist, the client can download the latest API components from the server.

Note: The Client Download Service ensures compatibility between client API versions and API versions on the Content Platform Engine. It does not ensure that a client will work with the latest version of the APIs, especially if the client was originally developed with API versions that are several releases behind the latest API versions. Also, the Client Download Service does not check for compatibility between Content Platform Engine API components and third-party components that a client application might require.

Download Service Components

The Client Download Service consists of the following server- and client-side components:

  • The Client Download Servlet runs within the Content Platform Engine and performs version-reporting and download operations.
  • The Client Download Java™ API is a library that enables a client application to connect to and request services from the Client Download Servlet.

Download Service Conceptual Model

The Client Download Service uses a hierarchical containment model to extract information and download components. At the top level is the Package class, which contains the features that a client application can leverage. For example, the IBM® Content Cortex package consists of content-based features, and the IBM FileNet® Process Engine package consists of process-based features. The Feature class documentation lists all of the resources available for download to a client.

A Feature contains components, the individual files that give a feature its functionality. From a Feature object, you can get configuration information about the components, as well as download the components. A component is represented by the Component class.

When you download components for a particular feature, the Client Download Java API writes an XML-based file manifest that identifies the components that were downloaded. The manifest serves as a record of the download operation, and can later be used to compare downloads from future versions of the Content Platform Engine.

Developer Requirements

To use the Client Download Service with a client application, you need:

  • The Client Download Servlet is included in the Content Platform Engine deployment.

    To test the connection to the Client Download Servlet, enter this URL in a web browser: http://<hostname>:<portnumber>/clientDownload?command=getVersion. (The default ports are 9080 for WebSphere® and 7001 for WebLogic.)

    If the connection is good, the Client Download Servlet returns version information about the Content Platform Engine.

  • Client Download Java API: Reference the client-download.jar file in your development environment.

    You can get the Client Download Java API from the Content Engine installation directory:

    • Windows: C:\Program Files (x86)\IBM\FileNet\ContentEngine\cdapi
    • non-Windows: /opt/IBM/FileNet/ContentEngine/cdapi

For requirements to develop a client that uses a Content Engine API, see Getting Started in the Java and .NET Developer's Guide.

For requirements to develop a client that uses a Process Engine API, see Introduction to Process Applications in the Process Java Developer's Guide.

Best Practices

  • Because the download operation overwrites any files that already exist in the specified download location, the client application should back up existing files before it downloads new files from the server.
  • If you want the client application to keep a history of downloaded files across Content Platform Engine versions, use a separate download directory for each new version of files downloaded from the server. First, download to a version-specific directory, and then copy the current files to the applicable runtime directories.