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Difference between revisions of "SMILA/Documentation/Filesystem Crawler"

(Crawling configuration explanation)
(Crawling configuration explanation)
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*** <tt>Name</tt> (required) – attributes name.
 
*** <tt>Name</tt> (required) – attributes name.
 
*** <tt>HashAttribute</tt> – specify if the attribute is used for the hash used for delta indexing (true or false). Must be true for at least one attribute which must always have a value.
 
*** <tt>HashAttribute</tt> – specify if the attribute is used for the hash used for delta indexing (true or false). Must be true for at least one attribute which must always have a value.
*** <tt>KeyAttribute</tt> – specify if the attribute is used for creating the record ID (true or false). Must be true for at least one attribute. All key attributes must identify the file uniquely, so usually you will use the "Path" FileAttribute for this.
+
*** <tt>KeyAttribute</tt> – specify if the attribute is used for creating the record ID (true or false). Must be true for at least one attribute. All key attributes must identify the file uniquely, so usually you will set it true for the attribute containing "Path" FileAttribute.
 
*** <tt>Attachment</tt> – specify if the attribute return the data as attachment of record.
 
*** <tt>Attachment</tt> – specify if the attribute return the data as attachment of record.
 
**** <tt>FileAttributes</tt> - specify the file attribute to write into the target attribute. The content of the element must be one of  
 
**** <tt>FileAttributes</tt> - specify the file attribute to write into the target attribute. The content of the element must be one of  

Revision as of 05:01, 14 September 2011

Overview

The file system crawler recursively fetches all files from a given directory. Besides providing the content of files, it may also gather any file's metadata from the following list:

  • full path
  • file name only
  • file size
  • last modified date
  • file content
  • file extension

Crawling configuration

The example configuration file is located at configuration/org.eclipse.smila.connectivity.framework/file.xml.

Defining Schema: org.eclipse.smila.connectivits.framework.crawler.filesystem/schemas/FileSystemDataSourceConnectionConfigSchema.xsd.

Crawling configuration explanation

The root element of crawling configuration is DataSourceConnectionConfig and contains the following sub elements:

  • DataSourceID – the identification of a data source
  • SchemaID – specifies the schema for a crawler job
  • DataConnectionID – describes which agent crawler should be used
    • Crawler – implementation class of a Crawler
    • Agent – implementation class of an Agent
  • CompoundHandling – specify if packed data (like a ZIP containing files) should be unpack and files within should be crawled (YES or NO).
  • Attributes – list all attributes which describe a file.
    • Attribute
      • Type (required) – the data type (String, Integer or Date).
      • Name (required) – attributes name.
      • HashAttribute – specify if the attribute is used for the hash used for delta indexing (true or false). Must be true for at least one attribute which must always have a value.
      • KeyAttribute – specify if the attribute is used for creating the record ID (true or false). Must be true for at least one attribute. All key attributes must identify the file uniquely, so usually you will set it true for the attribute containing "Path" FileAttribute.
      • Attachment – specify if the attribute return the data as attachment of record.
        • FileAttributes - specify the file attribute to write into the target attribute. The content of the element must be one of
          • Name: name of file, without the directory path
          • Path: complete path including file name.
          • Size: size in bytes.
          • LastModifiedDate: Date of last modification
          • Content: Content of file. Unconverted binary if written to an attachment. Else the crawler tries to detect the encoding and converts the content to a string (with fallbacks to UTF-8 or default encoding of the operating system).
          • FileExtension: The part of the filename after the last "." character (without the dot). An empty string if the filename does not contain a dot.
  • Process – contains parameters for gathering data.
    • BaseDir – the directory the crawling process begin (if is null, cannot be found/access or is not a directory a CrawlerCriticalException will be thrown).
      • Filter – select file type and crawling mode.
        • Recursive – (true or false).
        • CaseSensitive – true or false
      • Include – file to crawl.
        • Name - String e.g. "*.txt" (crawl all text files). Everything that is not included is excluded automatically. You could use a star * as wildcard.
      • Exclude – files to leave out while crawling.
        • Name – String e.g. "*test*" (leave out all text files which have test in the filename).

Crawling configuration example

<DataSourceConnectionConfig
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:noNamespaceSchemaLocation="../org.eclipse.smila.connectivity.framework.crawler.filesystem/schemas/FileSystemDataSourceConnectionConfigSchema.xsd">
  <DataSourceID>file</DataSourceID>
  <SchemaID>org.eclipse.smila.connectivity.framework.crawler.filesystem</SchemaID>
  <DataConnectionID>
    <Crawler>FileSystemCrawlerDS</Crawler>
  </DataConnectionID>
  <CompoundHandling>Yes</CompoundHandling>
  <Attributes>
    <Attribute Type="Date" Name="LastModifiedDate" HashAttribute="true">
      <FileAttributes>LastModifiedDate</FileAttributes>
    </Attribute>
    <Attribute Type="String" Name="Filename">
      <FileAttributes>Name</FileAttributes>
    </Attribute>
    <Attribute Type="String" Name="Path" KeyAttribute="true">
      <FileAttributes>Path</FileAttributes>
    </Attribute>
    <Attribute Type="String" Name="Content" Attachment="true">
      <FileAttributes>Content</FileAttributes>
    </Attribute>
    <Attribute Type="String" Name="Extension"
      <FileAttributes>FileExtension</FileAttributes>
    </Attribute>
    <Attribute Type="String" Name="Size">
      <FileAttributes>Size</FileAttributes>
    </Attribute>    
  </Attributes>
  <Process>
    <BaseDir>c:\data</BaseDir>
    <Filter Recursive="true" CaseSensitive="false">
      <Include Name="*.txt"/>
      <Include Name="*.htm"/>
      <Include Name="*.html"/>
      <Include Name="*.xml"/>     
    </Filter>
  </Process>
</DataSourceConnectionConfig>

Output example for default configuration

For a text file named crawler.txt located in c:/data the crawler will create the following record:

<Record xmlns="http://www.eclipse.org/smila/record" version="2.0">
  <Val key="_recordid">file:&lt;Path=c:\data\crawler.txt&gt;</Val>
  <Val key="_source">file</Val>
  <Val key="LastModifiedDate" type="datetime">2009-02-25T17:44:46+0100</Val>
  <Val key="Path">c:\data\crawler.txt</Val>
  <Val key="Filename">crawler.txt</Val>
  <Val key="Extension">txt</Val>
  <Val key="Size" type="long">36</Val>
  <Val key="_HASH_TOKEN">66f373e6f13498a65c7f5f1cf185611e94ab45630c825cc2028dda38e8245c7</Val>
  <Attachment>Content</Attachment>
</Record>

See also