External metadata

Switch offers substantial support for importing, exporting, transforming and using metadata through a combination of:

• Standard tools for picking up and exporting metadata associated with a job.

• Complete access to metadata from the Switch scripting environment.

For example, using simple script expressions you can route a job and set its processing parameters based on metadata provided with the job.

Also see metadata overview.

Picking up metadata

Switch allows permanently associating metadata with a job moving through the flow (by storing a reference to it in the job's internal job ticket). Each distinct set of metadata fields (for example, a JDF job ticket or an XMP packet) are stored in a separate metadata dataset. Switch supports several types of datasets, each with a specific data model that determines the semantics for querying values from the dataset. See below for information on supported data models.

Metadata can originate from a number of different sources including a job ticket provided with a job, an XMP packet embedded in a file, statistics derived from a file's contents and manual data entry through SwitchClient. Certain flow elements, including several built-in metadata pickup tools, can associate a new metadata dataset with a job being processed through the tool. Each dataset is given a unique name. Therefore, multiple datasets of the same type can be associated with a job (for example: two JDF job tickets, each in its own dataset with a distinct name).

To pickup metadata from a particular source, a flow designer must explicitly place the appropriate pickup tool or configurator in the flow, at a location before the metadata is actually queried. See below for a list of typical metadata sources and the corresponding Switch tools.

Using metadata

The Switch scripting API provides access to the contents of all metadata datasets already associated with a job and offers the appropriate functions for querying metadata values in each dataset, depending on its data model. Furthermore, the scripting API allows adding a new dataset or replacing an existing one.

Using script expressions, a flow can route a job and set its processing parameters based on the contents of metadata fields associated with the job. Script elements offer complete freedom for importing, exporting, transforming and using metadata at will.

Variables in the Metadata group provide access to any external metadata field associated with a job. Switch allows the use of variables in the values of many text properties and for defining file filters.

Updating metadata

The datasets picked up in the manner described above are called external datasets, as opposed to the embedded dataset which references information stored inside the file - see embedded metadata.

Switch does not support updating the value of individual metadata fields within an external dataset. This limitation does not apply to an embedded dataset (see Read-write access through scripting) or to hierarchy info and email info (which is stored directly in the internal job ticket and not in a metadata dataset).

Note that, despite this limitation, it is possible to replace an external dataset as a whole by a new version.

Exporting and transforming metadata

Any metadata dataset associated with a job can be exported as a separate file (in the same format) using the export metadata tool. The result can be further transformed to an appropriate XML, HTML or text file using the XSLT transform tool.

Metadata data models

Switch supports the following metadata data models and corresponding querying mechanisms:

Metadata resources

The following table lists various metadata sources and the corresponding metadata data models. The default dataset name can be overridden in most cases to allow associating more than one dataset of the same type with a job.