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Introduction

...

<Parameter name="org.apache.oodt.cas.curator.metExtractorConf.uploadPath"
                value="/usr/local/extractors" />    

We are going to make a metadata extractor that will extractor ID3 tag metadata, such as author, title, resource type, etc from mp3s. As a first step, we will create a directory for the new extractor. The name of this directory is important, because CAS-Curator will use the directory name to register the extractor. We will name this directory mp3extractor

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java -jar tika-app-1.4.jar -m \
    /usr/local/staging/products/mp3/Bach-SuiteNo2.mp3
Author: Johann Sebastian Bach
Content-Type: audio/mpeg
resourceName: Bach-SuiteNo2.mp3
title: Bach Cello Suite No 2  

With a little AWK magic, we can convert this output to the Cas-Metadata xml format:

java -jar tika-app-1.4.jar -m \
  /usr/local/staging/products/mp3/Bach-SuiteNo2.mp3 | awk -F:\
  'BEGIN \
  {print "<cas:metadata xmlns:cas=\"http://oodt.jpl.nasa.gov/1.0/cas\">"}\
  {print "<keyval><key>"$1"</key><val>"substr($2,1)"</val></keyval>"}\
  END {print "</cas:metadata>"}'
<cas:metadata xmlns:cas="http://oodt.jpl.nasa.gov/1.0/cas">
<keyval><key>Author</key><val>Johann Sebastian Bach</val></keyval>
<keyval><key>Content-Type</key><val>audio/mpeg</val></keyval>
<keyval><key>resourceName</key><val>Bach-SuiteNo2.mp3</val></keyval>
<keyval><key>title</key><val>Bach Cello Suite No 2</val></keyval>
</cas:metadata>            

Cool as a one line format translator is, we are actually going to have to do a little more work to create an extractor capable of producing metadata for CAS-Curator. A requirement for metadata extractors that are to be integrated with CAS-Curator is that they product three pieces of metadata:
ProductType
FileLocation
Filename
We should note that this is NOT a general requirement of all metadata extractors, but a ramification of the current implementation of CAS-Curator. In order to product this extra metadata, we will develop a small Python script:

#!/usr/bin/python

import os
import sys

fullPath = sys.argv[1]
pathElements = fullPath.split("/");
fileName = pathElements[len(pathElements)-1]
fileLocation = fullPath[:(len(fullPath)-len(fileName))]
productType = "MP3"

cmd = "java -jar /Users/woollard/Desktop/extractors/mp3extractor/"
cmd += "tika-app-1.4.jar -m "+fullPath+" | awk -F:"
cmd += " 'BEGIN {print \"<cas:metadata xmlns:cas="
cmd += "\\\"http://oodt.jpl.nasa.gov/1.0/cas\\\">\"}" 
cmd += " {print \"<keyval><key>\"$1\"</key><val>\"substr($2,1)\""
cmd += "</val></keyval>\"}' > "+fileName+".met"

os.system(cmd)

f = open(fileName+".met", 'a')
f.write('<keyval><key>ProductType</key><val>'+productType)
f.write('</val></keyval>\n<keyval><key>Filename</key><val>')
f.write(fileName+'</val></keyval>\n<keyval><key>FileLocation')
f.write('</key><val>'+fileLocation+'</val></keyval>\n')
f.write('</cas:metadata>')
f.close()

...

Now that we have a metadata extractor that meets our requirements (it's callable from the command-line, it produces CAS-Metadata compatible XML, and it extracts ProductType, Filename, and FileLocation), the next step is to create an ExternMetExtractor configuration file. This file will configure CAS-Metadata's ExternMetExtractor to call the mp3PythonExtractor.py script correctly.
There is more information about ExternMetExtractor configuration available in CAS-Metadata's Extractor Basics User's Guide. For the purposes of this guide, we will assume that the reader is familiar with configuration of this extractor, so we will just present the configuration below (we assume that you name this file mp3PythonExtractor.config):

    
<?xml version="1.0" encoding="UTF-8"?>
<cas:externextractor xmlns:cas="http://oodt.jpl.nasa.gov/1.0/cas">
   <exec workingDir="">
      <extractorBinPath>
/usr/local/extractors/mp3extractor/mp3PythonExtractor.py
      </extractorBinPath>
      <args>
         <arg isDataFile="true"/>
      </args>
   </exec>
</cas:externextractor>

...

cd /usr/local/extractors/mp3extractor
ls -l
total 51448
-rw-r--r--  1 -  -       167 Nov 27 13:50 config.properties
-rw-r--r--  1 -  -       328 Nov 27 13:49 mp3PythonExtractor.config
-rwxr-xr-x  1 -  -       702 Nov 27 13:49 mp3PythonExtractor.py
-rw-r--r--  1 -  -  26325155 Nov 27 13:46 tika-app-01.5-SNAPSHOT4.jar

Once you restart Tomcat, the change you have made to the context file will be used. The extractor area will now be set to /usr/local/extractors.

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The final step in our basic configuration of CAS-Curator is to configure a CAS-Filemgr instance into which we will ingest our mp3s. There is a lot of information on configuring the CAS-Filemgr in its User's Guide. We will assume familiarity with the CAS-Filemgr for the remainder of this guide.
In this guide, we will focus on the basic configuration necessary to tailor a vanilla build of the CAS-Filemgr for use with our CAS-Curator. We will assume that you have built the latest release of the CAS-Filemgr (v1.8.0 at the time of this writing) and installed it at:
/usr/local/srcoodt/cas-filemgr-1.8.0//

The first step in configuring the CAS-Filemgr is to edit the filemgr.properties file in the etc directory. This file controls the basic configuration of the CAS-Filemgr, including its various extension points. For this example, we are going to run the CAS-Filemgr in a very basic configuration, with both its repository and validation layer controlled by XML configuration, a local data transfer factory, and a Lucene-based metadata catalog.
In order to create this configuration, we will change the following parameters in the filemgr.properties file:
Set org.apache.oodt.cas.filemgr.catalog.lucene.idxPath to /usr/local/srcoodt/cas-filemgr-1.8.0/catalog. This parameter tells CAS-Filemgr where to create the Lucene index. The first time you start the CAS-Filemgr, make sure that this file does NOT exist. The CAS-Filemgr will take care of creating it and populating it with the appropriate files.
Set org.apache.oodt.cas.filemgr.repositorymgr.dirs to file:///usr/local/srcoodt/cas-filemgr-1.8.0/policy/mp3Image Removed. The value needs to be a URL and we are pointing to a policy folder we will create.
Set org.apache.oodt.cas.filemgr.validation.dirs to file:///usr/local/srcoodt/cas-filemgr-1.8.0/policy/mp3Image Removed. Like the last parameter we configured, this parameter should be a URL and point to the same policy folder.
With these changes, you are ready to run the basic configuration of the CAS-Filemgr. In order to make this install of CAS-Filemgr work with our CAS-Curator, however, we will also need to augment the basic policy for both the repository manager and validation layer.
First, we will create a policy directory for our mp3 curator. We can do this by moving the current policy files from the base policy directory to a mp3 directory:

cd /usr/local/srcoodt/cas-filemgr-1.8.0/policy
mkdir mp3
mv *.xml mp3/    

Next, we will add a product type to our instance of the CAS-Filemgr. In order to do this, we will edit the product-types.xml file in the policy/mp3 directory. We will add the following as a child of the <cas:producttypes> node (we purposefully elide any commentary on the details of this configuration and leave it to the reader):

 
<type id="urn:example:MP3" name="MP3">
  <repository path="file:///usr/local/archive"/>
  <versioner class="org.apache.oodt.cas.filemgr.versioning.BasicVersioner"/>
  <description>A product type for mp3 audio files.</description>
  <metExtractors>
    <extractor
   class="org.apache.oodt.cas.filemgr.metadata.extractors.CoreMetExtractor">
      <configuration>
        <property name="nsAware" value="true" />
        <property name="elementNs" value="CAS" />
        <property name="elements"
              value="ProductReceivedTime,ProductName,ProductId" />
      </configuration>
    </extractor>
  </metExtractors>
</type>

Next, we will create a number of elements in the elements.xml file. There will be an element node for each of the metadata elements we want to associate with MP3 products. We can do this be adding the following as children nodes of <cas:elements> tag:

      
<element id="urn:example:FileLocation" name="FileLocation">
  <dcElement/>
  <description/>
</element>
<element id="urn:example:ProductType" name="ProductType">
  <dcElement/>
  <description/>
</element>
<element id="urn:example:Author" name="Author">
  <dcElement/>
  <description/>
</element>
<element id="urn:example:Filename" name="Filename">
  <dcElement/>
  <description/>
</element>
<element id="urn:example:resourceName" name="resourceName">
  <dcElement/>
  <description/>
</element>
<element id="urn:example:title" name="title">
  <dcElement/>
  <description/>
</element>
<element id="urn:example:Content-Type" name="tContent-Type">
  <dcElement/>
  <description/>
</element> 

After we have configured the new metadata elements, we will need to map these elements to our MP3 product. We do this by editing the product-type-element-map.xml file in the policy/mp3 directory to add the following as a child node to <cas:producttypemap>:

        
<type id="urn:example:MP3">
  <element id="urn:example:FileLocation"/>
  <element id="urn:example:ProductType"/>
  <element id="urn:example:Author"/>
  <element id="urn:example:Filename"/>
  <element id="urn:example:resourceName"/>
  <element id="urn:example:title"/>
  <element id="urn:example:Content-Type"/> 
</type>

A final configuration step will be to create the archive area for the CAS-Filemgr (You'll remember that we set the repository path for MP3 products in the product-types.xml file). In order to do this, we will just make the directory:

...

We will now start the CAS-Filemgr instance. This instance will run on port 9000 by default. In order to start the Filemgr, we will issue the following commands:

cd /usr/local/srcoodt/cas-filemgr-1.8.0/bin/bin
./filemgr start

Now that we have started the CAS-Filemgr, we will need to configure the CAS-Curator to use this Filemgr instance. In order to do this, we will add the following parameters to the CAS-Curator context file:

    
<Parameter name="org.apache.oodt.cas.fm.url"
        value="http://localhost:9000"/>
            
<Parameter name="org.apache.oodt.cas.curator.dataDefinition.uploadPath"
        value="/usr/local/srcoodt/cas-filemgr-1.8.0/policy" />

<Parameter name="org.apache.oodt.cas.curator.fmProps"
        value="/usr/local/srcoodt/cas-filemgr-1.8.0/etc/filemgr.properties"/>        

Once we restart Tomcat, the CAS-Curator will now recognize the policy and properties of the configured CAS-Filemgr instance and use this instance during the ingest process.

...

> ls -lR /usr/local/archive
total 0
drwxr-xr-x  3 -  - 102 Nov 27 23:53 Bach-SuiteNo2.mp3

/usr/local/archive//Bach-SuiteNo2.mp3:
total 9344
-rw-r--r--  1 -  -  4781079 Nov 25 20:14 Bach-SuiteNo2.mp3

...

Worth noting is the fact that our configuration of the CAS-Filemgr included a selection of the {{BasicVersioner}} as the MP3 product type versioner. This means that mp3s are placed at \[the BasicVersioner as the MP3 product type versioner. This means that mp3s are placed at \archive_base\]/\[filename\]/\[filename\ ] during ingest.
We have now completed a base configuration of the CAS-Curator. In the [Advanced Guide|http://oodt.apache.org/components/maven/curator/user/advanced.html], we will cover topics like changing the look and feel of the Curator, and security configuration.