Preference settings

Transcoding Technology uses preference profiles to represent the characteristics of devices, and a default user profile to represent organizational policies. Each profile tells Transcoding Technology how to treat documents that will be delivered to that device or user.

A preference profile can represent a particular type of device, such as a PDA. Using the preference profiles, Transcoding Technology can determine the specific set of preference parameters that govern the processing of each request. For example, on a device with limited processing capability, you might want to convert tables to lists to reduce the processing required to present the page.

A profile does not have to include a value for each preference. If a value is not specified for a preference, Transcoding Technology's preference aggregator will determine an appropriate value based on all the profiles involved in the transaction. If no value is supplied, the transcoding plugin requesting the preference value will specify a default. The transformations that will be applied to the document are selected based on the combined preferences.

When the WebSphere Portal uses Transcoding Technology to process a request, it selects the first client with a User-Agent value that matches the content of the User-Agent header of the request. The WebSphere Portal passes the selected client information to Transcoding Technology in the request, so Transcoding Technology can use the appropriate preference profile for the selected client.

Transcoding Technology provides preference profiles for each WebSphere Portal client. The profiles for clients are named based on the client property values of: [Manufacturer-valuep[,Model-value[,Version-value.prop]]]. If the WebSphere Portal cannot match the User-Agent to a client, it identifies the client as default, with no Manufacturer, Model or Version. Transcoding Technology uses the default profile, named default.prop, for that client.

You can add additional preference profiles to Transcoding Technology for clients not included in the WebSphere Portal, or update or delete Transcoding Technology preference profiles. To add a preference profile to Transcoding Technology:

  1. Add the new client to the WebSphere Portal using the XML configuration interface client, or the WebSphere Portal Administration Portlet. See the WebSphere Portal documentation for more information. The WebSphere Portal notifies Transcoding Technology that a new client exists. Transcoding Technology then creates a new preference profile for that client.

  2. Once Transcoding Technology has created the preference profile for the new client, you can use Transcoding Technology's XML Configuration to modify the profile with properties related to transcoding capabilities and preferences.

 

Preference Names

Each preference has a literal name, such as screenCapability, which is used in preference profiles, and a defined variable constant name, such as SCREEN_CAPABILITY, whose value is set to the literal name. Use the literal name to access the preference value in a stylesheet or annotator and to make modifications to preference profiles.

A preference profile can also represent a specific user. Transcoding Technology will use the preferences of a specific user instead of the default user in every case, except when you have specified either:

Transcoding Technology does not provide a method for modifying user preferences. To use user preferences, provide the name of a user profile to Transcoding Technology. For more information about how to obtain a user's identity for user preferences, see Resources.

 

Set page size

Limiting page size enhances device perfomance and prevents problems that arise from handling excessively large pages. The page size for devices such as HTML browsers, PDAs and cell phones is defined in [WP_HOME]/IBMTrans/etc/preferences/device/*.prop, where [WP_HOME] is the root WebSphere Portal directory, and * is the device profile name, created from the manufacturer name, model name and version number. For example, Pixo MicroBrowser version 2.1 would be combined to form the name Pixo!MicroBrowser!2.1.prop.

The following properties control page size:

To change the page size, open the prop file. Add or modify the value WMLMaximumDeckSize=[size in bytes] or HTMLMaximumPageSize=[size in bytes], depending on the device. For example, the following property sets the maximum page size for an iMode compact HTML document at 2048 bytes:

HTMLMaximumPageSize=2048

 

See also