Configure Element Extraction for XML Documents
When filtering XML files, you can specify which elements and attributes are extracted according to the file's format ID or root element. This is useful when you want to extract only relevant text elements, such as abstracts from reports, or a list of authors from an anthology.
A root element is an element in which all other elements are contained. In the XML sample below, book
is the root element:
<book> <title>XML Introduction</title> <product id="33-657" status="draft">XML Tutorial</product> <chapter>Introduction to XML <para>What is HTML</para> <para>What is XML</para> </chapter> <chapter>XML Syntax <para>Elements must have a closing tag</para> <para>Elements must be properly nested</para> </chapter> </book>
For example, you could specify that when filtering files with the root element book
, the element title
is extracted as metadata, and only product
elements with a status
attribute value of draft
are extracted. When you extract an element, the child elements within the element are also extracted. For example, if you extract the element chapter
from the sample above, the child element para
is also extracted.
Filter SDK defines default element extraction settings for the following XML formats:
- generic XML
- Microsoft Office 2003 XML (Word, Excel, and Visio)
- StarOffice/OpenOffice XML (text document, presentation, and spreadsheet)
These settings are defined internally and are used when filtering these file formats; however, you can modify their values.
In addition to the default extraction settings, you can also add custom settings for your own XML document types. If you do not define custom settings for your own XML document types, the settings for the generic XML are used.
Modify Element Extraction Settings
You can modify configuration settings for XML documents through a configuration file. An example configuration file, kvxconfig.ini
, is provided with the Filter SDK. To use this, set the XMLConfigInfo
property of the Filter
class to the path of your configuration file. For example:
filter.XMLConfigInfo = "kvxconfig.ini";
Modify Element Extraction Settings in the kvxconfig.ini File
The kvxconfig.ini
file contains default element extraction settings for supported XML formats. The file is in the directory install\OS\bin
, where install
is the path of the Filter installation directory and OS
is the name of the operating system. For example, the following entry defines extraction settings for the Microsoft Visio 2003 XML format:
[config3] eKVFormat=MS_Visio_XML_Fmt szRoot= szInMetaElement=DocumentProperties szExMetaElement=PreviewPicture szInContentElement=Text szExContentElement= szInAttribute=
The following options are available:
Configuration Option | Description |
---|---|
eKVFormat
|
The format ID as detected by the KeyView detection module. This determines the file type to which these extraction settings apply. See Obtain Format Information for more information on format ID values. If you are adding configuration settings for a custom XML document type, this option is not defined. |
szRoot
|
The file's root element. When the format ID is not defined, the root element is used to determine the file type to which these settings apply. To further qualify the element, specify its namespace. See Specify an Element's Namespace and Attribute. |
szInMetaElement
|
The elements extracted from the file as metadata. All other elements are extracted as text. Separate multiple entries with commas. To further qualify the element, specify its namespace, its attributes, or both. See Specify an Element's Namespace and Attribute. |
szExMetaElement
|
The child elements in the included metadata elements that are not extracted from the file as metadata. For example, the default extraction settings for the Visio XML format extract the You cannot exclude any metadata elements from the output for StarOffice files. All metadata is extracted regardless of this setting. Separate multiple entries with commas. To further qualify the element, specify its namespace, its attributes, or both. See Specify an Element's Namespace and Attribute. |
szInContentElement
|
The elements extracted from the file as content text. Enter an asterisk (*) to extract all elements including child elements. Separate multiple entries with commas. To further qualify the element, specify its namespace, its attributes, or both. See Specify an Element's Namespace and Attribute. |
szExContentElement
|
The child elements in the included content elements that are not extracted from the file as content text. Separate multiple entries with commas. To further qualify the element, specify its namespace, its attributes, or both. See Specify an Element's Namespace and Attribute. |
szInAttribute
|
The attribute values extracted from the file. Enter an asterisk (*) for the attribute name to extract all attribute values. If attributes are not defined here, attribute values are not extracted. Enter the namespace (if used), element name, and attribute name in the following format:
For example:
Separate multiple entries with commas. |
Specify an Element's Namespace and Attribute
To further qualify an element, you can specify that the element exist in a certain namespace and/or contain a specific attribute. To define the namespace and attribute of an element, enter the following:
ns_prefix:elemname@attribname=attribvalue
NOTE: Attribute values that contain spaces must be enclosed in quotation marks.
For example, the entry bg:language@id=xml
extracts a language
element in the namespace bg
that contains the attribute name id
with the value of "xml"
. This entry extracts the following element from an XML file:
<bg:language id="xml">XML is a simple, flexible text format derived from SGML</bg:language>
but does not extract:
<bg:language id="sgml">SGML is a system for defining markup languages.</bg:language>
or
<adv:language id="xml">The namespace should be a Uniform Resource Identifier (URI).</adv:language>
Add Configuration Settings for Custom XML Document Types
You can define element extraction settings for custom XML document types by adding the settings to the kvxconfig.ini
file. For example, for files that contain the root element microfocusxml
, we could add the following section to the end of the initialization file:
[config101] eKVFormat= szRoot=microfocusxml szInMetaElement=dc:title,dc:meta@title,dc:meta@name=title szExMetaElement= szInContentElement=microfocus:division@name=keyview,microfocus:division@name=idol,p@style="Heading 1" szExContentElement= szInAttribute=microfocus:division@name
The custom extraction settings must be preceded by a section heading named [configN]
, where N
is an integer starting at 100 and increasing by 1 for each additional file type, as in [config100]
, [config101]
, [config102]
, and so on. The default extraction settings for the supported XML formats are numbered config0
to config99
. Currently only 0
to 6
are used.
Since a custom XML document type is not recognized by the KeyView detection module, the format ID is not defined. The file type is identified by the file's root element only.
If a custom XML document type is not defined in the configuration file, the default extraction settings for a generic XML document are used.