Chapter 55 Robot Application Functions

The following functions are used in the Generate stage of filtering. Generation functions can generate information that goes into a resource description. In general, they either extract information from the body of the resource itself or copy information from the resource’s metadata.

extract-full-text

The extract-full-text function extracts the complete text of the resource and adds it to the resource description.



Note	The extract-full-text function should be used with caution, because it can significantly increase the size of the resource description, thus causing database bloat and overall negative impact on network bandwidth.

Parameters

The following table lists the parameters used with the extract-full-text function. The table contains two columns. The first column lists the parameter, and the second column provides a description.


truncate	The maximum number of characters to extract from the resource.
dst	Name of the schema item that will receive the full text.

Example

extract-html-meta

The extract-html-meta function extracts any <META> or <TITLE> information from an HTML file and adds it to the resource description. A content-type may be specified to restrict the kind of URLs that are generated.

Parameters

The following table lists the parameters used with the extract-html-meta function. The table contains two columns. The first column lists the parameter, and the second column provides a description.


truncate	The maximum number of bytes to extract.
type	Optional parameter. If omitted, it will generate all URLs.

Example

extract-html-text

The extract-html-text function extracts the first few characters of text from an HTML file, excluding the HTML tags, and adds the text to the resource description. This permits the first part of a document’s text to be included in the RD. A content-type may be specified to restrict the kind of URLs that are generated.

Parameters

The following table lists the parameters usedwith the extract-html-text function. The table contains two columns. The first column lists the parameter, and the second column provides a description.


truncate	The maximum number of bytes to extract.
skip-headings	Set to true to ignore any HTML headers that occur in the document.
type	Optional parameter. If omitted, it will generate all URLs.

Example

extract-html-toc

The extract-html-toc function extracts the table-of-contents from the HTML headers and add it to the resource description.

Parameters

The following table lists the parameters used with the extract-html-toc function. The table contains two columns. The first column lists the parameter, and the second column provides a description.


truncate	The maximum number of bytes to extract.
level	Maximum HTML header level to extract. This parameter controls the depth of the table of contents.

Example

extract-source

The extract-source function extracts the specified values from the given sources and adds them to the resource description.

Parameters

The following table lists the parameter used with the extract-source function. The table contains two columns. The first column lists the parameter, and the second column provides a description.


src	List of source names; you can use the -> operator to define a new name for the RD attribute, for example, type->content-type would take the value of the source named type and save it in the RD under the attribute named content-type.

Example

harvest-summarizer

The harvest-summarizer function runs a Harvest summarizer on the resource and adds the result to the resource description.

To run Harvest summarizers, you must have $HARVEST_HOME/lib/gatherer in your path before you run the robot.

Parameters

The following table lists the parameter used with the harvest-summarizer function. The table contains two columns. The first column lists the parameter, and the second column provides a description.


summarizer	Name of the summarizer program.