Running transformation script in Alfresco - pdf

Question

Why isn't my transformation script running on any uploaded files beyond the first file?
I set up a transformation rule in Alfresco that listens to a folder. When a new file is placed into the folder, the rule triggers a script to run that takes a PDF without a text layer, breaks it into jpegs, OCRs the jpegs, then converts the jpegs into PDFs and merges the PDFs, returning an OCRed PDF with a text layer then copies the result into another folder so we know it got done.
Running the script at command line works. The first time I drop a file into the Alfresco folder (upload) it runs the script and copies the file. But any subsequent time I drop files into the folder, the script isn't run, but the file is still copied to the target folder. So I know the rule is being called, but the script doesn't seem to be running on the following files. I have logging on the script, so I know the script isn't even getting called. The rule is being applied to all new and modified files in the folder with no filters. Then it runs the Transform and Copy command using our custom OCR script and with the target folder being defined as the parent folder.
Below is my alfresco transformation extension:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id="transformer.worker.PdfOCRTool" class="org.alfresco.repo.content.transform.RuntimeExecutableContentTransformerWorker">
<property name="mimetypeService">
<ref bean="mimetypeService"/>
</property>
<property name="transformCommand">
<bean name="transformer.pdftoocr.Command" class="org.alfresco.util.exec.RuntimeExec">
<property name="commandMap">
<map>
<entry key=".*">
<value>/opt/ocr/ocr.sh ${source} ${target}</value>
</entry>
</map>
</property>
<property name="errorCodes">
<value>1,2</value>
</property>
</bean>
</property>
<property name="explicitTransformations">
<list>
<bean class="org.alfresco.repo.content.transform.ExplictTransformationDetails">
<property name="sourceMimetype">
<value>application/pdf</value>
</property>
<property name="targetMimetype">
<value>application/pdf</value>
</property>
</bean>
</list>
</property>
</bean>
<bean id="transformer.proxy.PdfOCRTool" class="org.alfresco.repo.management.subsystems.SubsystemProxyFactory">
<property name="sourceApplicationContextFactory">
<ref bean="thirdparty"/>
</property>
<property name="sourceBeanName">
<value>transformer.worker.PdfOCRTool</value>
</property>
<property name="interfaces">
<list>
<value>org.alfresco.repo.content.transform.ContentTransformerWorker</value>
</list>
</property>
</bean>
<bean id="transformer.PdfOCRTool" class="org.alfresco.repo.content.transform.ProxyContentTransformer" parent="baseContentTransformer">
<property name="worker">
<ref bean="transformer.proxy.PdfOCRTool"/>
</property>
</bean>
</beans>

Answer 1

The transformation service is intended for converting items from one mimetype to another. I am not sure that converting from PDF to a second PDF is valid. You would be better implementing a custom Java repository action which then in turn uses a org.alfresco.util.exec.RuntimeExec bean to fire off the command.
Since your Spring config already defines a RuntimeExec bean, you could re-use this definition but wrap it instead in your own custom class which extends org.alfresco.repo.action.executer.ActionExecuterAbstractBase. In fact, if you take a look at the source of org.alfresco.repo.action.executer.TransformActionExecuter then that might give you some clues on how to go about implementing things.