# 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 either the API or the `kvxconfig.ini` file.

## Use an Initialization File

To modify the settings for the standard XML document types, or add configuration settings for your own XML document types, follow these steps:

1. Modify the `kvxconfig.ini` file.
2. Use the initialization file when processing the XML file. See Modify Element Extraction Settings in the kvxconfig.ini File.

## 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 name 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 File Format Detection for more information on format ID values. If you are adding configuration settings for a custom XML document type, this 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 `DocumentProperties` element as metadata. This element includes child elements such as `Title`, `Subject`, `Author`, `Description`, and so on. However, the child element `PreviewPicture` is defined in `szExMetaElement` because it is binary data and should not be extracted. 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. 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: `namespace:elementname@attributename` For example: `microfocus:division@name` 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 `kvxconfig.ini` file or by the `SetConfigOption` method, then the default extraction settings for a generic XML document are used.

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