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Problems when PDF document transfers through WebService

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cheney zhao

Problems when PDF document transfers through WebService

Hi, All,
I faced a strange problem when viewing PDF files.
When I view the pdf file in IE directly through the following xpl:
<p:processor name="oxf:url-generator">
<p:input name="config" transform="oxf:unsafe-xslt" href="#instance">
<config xsl:version="2.0">
<url>file:\\temp\test.pdf</url>
<content-type>application/pdf</content-type>
</config>
</p:input>
<p:output name="data" ref="data" />
</p:processor>
It works fine. But when I make the xpl above as a webservice, call this webservice by the Document-Style in the following xpl:

<p:processor name="oxf:delegation">
<p:input name="interface" href="#service-interface"/>
<p:input name="call" href="#service-call"/>
<p:output name="data" id="service-result" debug="data"/>
</p:processor>

<p:processor name="oxf:xslt">
<p:input name="data" href="#service-result"/>
<p:input name="config">
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
<xsl:template match="*">
<xsl:element name="{local-name()}">
<xsl:copy-of select="@*"/>
<xsl:apply-templates/>
</xsl:element>
</xsl:template>
</xsl:stylesheet>
</p:input>
<p:output name="data" id="test" ref="data"/>
</p:processor>
The output of two pipelines are same:
<document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xs:base64Binary" content-type="application/pdf" last-modified="Tue, 16 Oct 2007 08:09:51 GMT">JVBERi0xLjUKJeLjz9MKMSAwIG9iaiA8PC9UeXBlL01ldGFkYXRhL0xlbmd0aC</document>
But I got the exception when invoking by this style:

ERROR ProcessorService - Exception at line 327, column 53 of oxf:/config/epilogue-servlet.xpl (executing processor: name='{http://www.orbeon.com/oxf/processors}http-serializer')
java.lang.NullPointerException
at org.orbeon.oxf.processor.serializer.BinaryTextContentHandler.characters(BinaryTextContentHandler.java:177)
at org.orbeon.oxf.xml.SAXStore.replay(SAXStore.java:197)
Is there something changed during the transfer of webservice? I'm confused when the output of two pipelines have no difference?

cheney zhao

Re: Problems when PDF document transfers through WebService

Thanks for your useful explanation!

Alessandro Vernet

Re: Problems when PDF document transfers through WebService

Administrator

In reply to this post by cheney zhao

On Oct 27, 2008, at 8:43 AM, cheney zhao <[hidden email]> wrote:

> I faced a strange problem when viewing PDF files.
> When I view the pdf file in IE directly through the following xpl:
> <p:processor name="oxf:url-generator">
> <p:input name="config" transform="oxf:unsafe-xslt"
> href="#instance">
> <config xsl:version="2.0">
> <url>file:\\temp\test.pdf</url>
> <content-type>application/pdf</content-type>
> </config>
> </p:input>
> <p:output name="data" ref="data" />
> </p:processor>
> It works fine. But when I make the xpl above as a webservice, call
> this
> webservice by the Document-Style in the following xpl:
> [...]
> The output of two pipelines are same:
> <document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
> xsi:type="xs:base64Binary" content-type="application/pdf"
> last-modified="Tue, 16 Oct 2007 08:09:51
> GMT">JVBERi0xLjUKJeLjz9MKMSAwIG9iaiA8PC9UeXBlL01ldGFkYXRhL0xlbmd0aC</
> document>
> But I got the exception when invoking by this style:
>
> ERROR ProcessorService - Exception at line 327, column 53 of
> oxf:/config/epilogue-servlet.xpl (executing processor:
> name='{http://www.orbeon.com/oxf/processors}http-serializer')
> java.lang.NullPointerException

The pipeline that reads the PDF produces an XML document that contains
the binary PDF encoded in base64. This is how binary data can be
passed around in pipelines, since all the inputs and outputs of
pipelines and processors have to be XML. Now if your pipeline is
referenced from the page flow (view="pipeline.xpl"), then the output
goes to the epilogue which understand this as an XML document and
returns the binary data in the HTTP response instead of the XML
document.

When you expose the XPL as a service you want the XML document to be
returned. There are a few ways to do this. Maybe the simplest is to
remove the xsi:type attribute on the document produced by the URL
generator, say with an XSLT stylesheet just after the URL generator.

Alex
--
Orbeon Forms - Web 2.0 Forms, open-source, for the Enterprise
Orbeon's Blog: http://www.orbeon.com/blog/
Personal Blog: http://avernet.blogspot.com/
Twitter - http://twitter.com/avernet

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cheney zhao

Re: Problems when PDF document transfers through WebService

Thank you , Alex, I have fixed this problem.

Alessandro Vernet wrote

On Oct 27, 2008, at 8:43 AM, cheney zhao <cauzcy@126.com> wrote:
> I faced a strange problem when viewing PDF files.
> When I view the pdf file in IE directly through the following xpl:
> <p:processor name="oxf:url-generator">
> <p:input name="config" transform="oxf:unsafe-xslt"
> href="#instance">
> <config xsl:version="2.0">
> <url>file:\\temp\test.pdf</url>
> <content-type>application/pdf</content-type>
> </config>
> </p:input>
> <p:output name="data" ref="data" />
> </p:processor>
> It works fine. But when I make the xpl above as a webservice, call
> this
> webservice by the Document-Style in the following xpl:
> [...]
> The output of two pipelines are same:
> <document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
> xsi:type="xs:base64Binary" content-type="application/pdf"
> last-modified="Tue, 16 Oct 2007 08:09:51
> GMT">JVBERi0xLjUKJeLjz9MKMSAwIG9iaiA8PC9UeXBlL01ldGFkYXRhL0xlbmd0aC</
> document>
> But I got the exception when invoking by this style:
>
> ERROR ProcessorService - Exception at line 327, column 53 of
> oxf:/config/epilogue-servlet.xpl (executing processor:
> name='{http://www.orbeon.com/oxf/processors}http-serializer')
> java.lang.NullPointerException

The pipeline that reads the PDF produces an XML document that contains
the binary PDF encoded in base64. This is how binary data can be
passed around in pipelines, since all the inputs and outputs of
pipelines and processors have to be XML. Now if your pipeline is
referenced from the page flow (view="pipeline.xpl"), then the output
goes to the epilogue which understand this as an XML document and
returns the binary data in the HTTP response instead of the XML
document.

When you expose the XPL as a service you want the XML document to be
returned. There are a few ways to do this. Maybe the simplest is to
remove the xsi:type attribute on the document produced by the URL
generator, say with an XSLT stylesheet just after the URL generator.

Alex
--
Orbeon Forms - Web 2.0 Forms, open-source, for the Enterprise
Orbeon's Blog: http://www.orbeon.com/blog/
Personal Blog: http://avernet.blogspot.com/
Twitter - http://twitter.com/avernet

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For general help: mailto:sympa@ow2.org?subject=help
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-----
Orbeon Forms - Web 2.0 Forms, open-source, for the Enterprise
Orbeon's Blog: http://www.orbeon.com/blog/
Personal Blog: http://avernet.blogspot.com/
Twitter - http://twitter.com/avernet