Create compressed PDF from PDF

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loftux

I need to make compressed versions of a PDF:s available. The original PDF are scanned documents with very high resolution (they need to be since they are historical documents that are not always of best quality to start with) and therefor very large file sizes. Now I need to make compressed version of those files available for preview and download for faster page load.

My thinking is that I can use a new thumbnail definition for this.
For the compression I can use ghostscript like this http://www.alfredklomp.com/programming/shrinkpdf/ and put this into a transformer similar to the transformer.worker.Pdf2swf or transformer.worker.ImageMagick found in thirdparty subsystem.

But how do I go from there and tell the thumbnail definitions bean to use that transformer?
In the thumbnail definition I can set the target mimetype, but in this case it is the same (application/pdf).

loftux

I found that one can use imagemagick to compress pdf with

convert -compress jpeg -density 100 input.pdf output.pdf ‍

My line of thought then was that i could use this for a new thumbnail definition

   <bean id="loftux.thumbnail.pdfcompressed" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
      <property name="targetObject" ref="thumbnailRegistry" />
      <property name="targetMethod" value="addThumbnailDefinition" />
      <property name="arguments">
         <list>
            <bean class="org.alfresco.repo.thumbnail.ThumbnailDefinition">
               <property name="name" value="pdfcompressed" />
               <property name="mimetype" value="application/pdf"/>
               <property name="transformationOptions">
                  <bean parent="defaultImageTransformationOptions">
                     <property name="commandOptions">
                        <value>-compress jpeg -density 100 ${source} ${target}</value>
                     </property>
                  </bean>
               </property>
               <property name="runAs" value="System"/>
               <property name="failureHandlingOptions" ref="standardFailureOptions"/>
            </bean>
         </list>
      </property>
   </bean>

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This does not work unfortunately. I get the error
The content node was not specified so the content cannot be streamed to the client…
So something is wrong with my bean definition I guess.