Norconex is proud to release version 2.4.0 of its Norconex Importer open-source product.  In addition to the usual bug fixes and stability enhancements, this release provides more possibilities for parsing and enriching your documents.  Most significantly, Importer 2.4.0 allows for scripting and DOM navigation.  Keep reading for more details and usage samples.

Scripting

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Whereas it has always been possible to extend the importer to implement your own document processing logic, now you can inject the importer via configuration using a scripting language. The following new handlers enable the use of scripting languages to manipulate documents: ScriptFilter, ScriptTagger, and ScriptTransformer.

The “JavaScript” script engine, which is already present as part of your Java installation, is the script engine used by these classes.  The JavaScript engine used by the Oracle implementation of Java is based on Mozilla Rhino. You can find extensive JavaScript documentation on the Mozilla Rhino site.

Java developers can extend the importer to increase support for additional scripting languages. These new classes rely on JSR 223 API, which allows you to “plug” into any script engines to support your favorite scripting language.

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<!-- Reject documents that are not about "apple". -->
<filter class="com.norconex.importer.handler.filter.impl.ScriptFilter">
  <script><![CDATA[
      isAppleDoc = metadata.getString('fruit') == 'apple'
              || content.indexOf('Apple') > -1;
      /*return*/ isAppleDoc;
  ]]></script>
</filter>

<!-- Add a "fruit" metadata field with the value "apple". --> 
<tagger class="com.norconex.importer.handler.tagger.impl.ScriptTagger">
  <script><![CDATA[
      metadata.addString('fruit', 'apple');
  ]]></script>
</tagger>

<!-- Modify all occurences of "Alice" with "Roger". -->
<transformer 
    class="com.norconex.importer.handler.transformer.impl.ScriptTransformer">
  <script><![CDATA[
      modifiedContent = content.replace(/Alice/g, 'Roger');
      /*return*/ modifiedContent;
  ]]></script>
</transformer>

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DOM navigation

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It is now possible to reference elements of an HTML or XML document using friendly CSS or JQuery-like syntax to navigate its domain object model (DOM). The jsoup parser is used to load document content into a DOM tree.

The new DOMContentFilter can be used to reject documents containing a specific HTML/XML path or element. The DOMSplitter can be used to break HTML/XML with “list” elements into different documents. Finally, the DOMTagger allows you to extract specific HTML/XML tag values or attributes and store them in your own fields (e.g., extract <h1> tags into a “title” field).

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<!-- Exclude documents containing GIF images. -->
<filter class="com.norconex.importer.handler.filter.impl.DOMContentFilter"
      selector="img[src$=.gif]" onMatch="exclude" />

<!-- Store H1 tags in a title field. -->
<tagger class="com.norconex.importer.handler.tagger.impl.DOMTagger">
  <dom selector="h1" toField="title" overwrite="false" />
</tagger>

<!-- Create a new contact document for each occurence of the "contact" tag. -->
<splitter class="com.norconex.importer.handler.splitter.impl.DOMSplitter"
    selector="contact" />

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Other features

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This release features several other helpful and interesting changes and additions.  For instance, CharacterCaseTagger can now be used to adjust the character case of field names (in addition to values). A few additional file formats are also supported.  For a complete list of changes, see the release notes.

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<!-- Make every instance of "title" field name lowercase. -->
<tagger class="com.norconex.importer.handler.tagger.impl.CharacterCaseTagger">
  <characterCase fieldName="title" type="lower" applyTo="field" />
</tagger>

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Useful links

• Download Norconex Importer 2.4.0.
• Find out how to get started.
• Report your issues and questions on Github.
• Use the Importer as part of one of Norconex Collectors (open-source crawlers).

This release of Norconex Importer brings many fixes, increased stability, and nice new features. The following highlights some of the additions with XML configuration or Java code samples.

Retrieve a document Length

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Thanks to the new DocumentLengthTagger, you can now store a document byte length in a metadata field of your choice. The length can be obtained at any document processing stage.  For instance, it can be obtained before any transformation took place, or after it was parsed.

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<tagger class="com.norconex.importer.handler.tagger.impl.DocumentLengthTagger"
  field="doc-length" overwrite="true" >
</tagger>

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Add the current date to a document

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The new CurrentDateTagger allows to add the current date to a metadata field and date format of your choice. This can be useful to indicate when a document was actually processed by the Importer.

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<tagger class="com.norconex.importer.handler.tagger.impl.CurrentDateTagger"
  field="date-imported" format="yyyy-MM-dd" />

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Filter documents on numeric or date range

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NumericMetadataFilter and DateMetadataFilter now allow you to filter documents based on metadata field numeric or date values, respectively. You can define both closed ranges and open-ended ranges.

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<!-- Numeric range filter -->
<filter class="com.norconex.importer.handler.filter.impl.NumericMetadataFilter"
      onMatch="include" field="age" >
  <condition operator="ge" number="20" />
  <condition operator="lt" number="30" />
</filter>

<!-- Date range filter -->
<filter class="com.norconex.importer.handler.filter.impl.DateMetadataFilter"
      onMatch="include" field="publish_date" >
  <condition operator="ge" date="TODAY-7" />
  <condition operator="lt" date="TODAY" />
</filter>

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Use external parsers

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Wrapping a Tika class of the same name, the new ExternalParser allows Java programmers to point to external command-line applications to parse documents. One example can be for using “pdftotext” to parse PDFs instead of the default PDF parser based on PDFBox, which is much slower (but does a better job overall).

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import java.util.Map;

import com.norconex.commons.lang.file.ContentType;
import com.norconex.importer.parser.GenericDocumentParserFactory;
import com.norconex.importer.parser.IDocumentParser;
import com.norconex.importer.parser.impl.ExternalParser;

public class CustomDocumentParserFactory extends GenericDocumentParserFactory {

    @Override
    protected Map<ContentType, IDocumentParser> createNamedParsers() {
        Map<ContentType, IDocumentParser> parsers = super.createNamedParsers();

        ExternalParser pdfParser = new ExternalParser();
        pdfParser.setCommand(
                // Replace this with your own executable path
                "C:\\Apps\\pdftotext.exe", 
                "-enc", "UTF-8", "-raw", "-q", "-eol", "unix",                 
                ExternalParser.INPUT_FILE_TOKEN, 
                ExternalParser.OUTPUT_FILE_TOKEN);
        parsers.put(ContentType.PDF, pdfParser);
        return parsers;
    }
}

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Other improvements

There are more changes under the hood, like upgrading to Apache Tika 1.8, as well as the fixing of OutOfMemory errors and document parsing sometimes never returning. You can find the complete list of changes in the release notes.

Several of these improvements were made possible thanks to the great feedback of the open-source community. Keep doing so: you make a difference.

Useful links

• Download Norconex Importer 2.2.0.
• Find out how to get started.
• Report your issues and questions on Github.
• Use the Importer as part of one of Norconex Collectors (open-source crawlers).