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From Uwe Geisert <ugeis...@opentext.com>
Subject RE: Streaming capability with WS binding
Date Tue, 19 Nov 2013 10:15:35 GMT
Hi Florian,

I investigated the streaming issue a bit and found that "parseEagerly=true" in the JAX-WS
annotation

	@StreamingAttachment(parseEagerly = true, memoryThreshold = 4 * 1024 * 1204)

which is applied to OpenCMIS' ObjectService and VersioningService breaks streaming.
Setting it to false has the following effect:
- no MIME*.temp files in Tomcat's temp directory
- the content stream's read() is called only a few times before the service is invoked (whereas
with parseEagerly=true the complete content was read before the service's invokation and before
all handler invokations)
- in a small dev environment no negative performance impact was observed

Would you please explain what was the intention to user eager parsing?
Would it make sense to make this a configurable parameter as the memoryThreshold already is?

Thanks
Uwe



-----Original Message-----
From: Florian Müller [mailto:fmui@apache.org] 
Sent: Mittwoch, 23. Oktober 2013 19:36
To: dev@chemistry.apache.org
Cc: Uwe Geisert
Subject: Re: Streaming capability with WS binding

 Hi Uwe,

 The abilities to stream, buffer in memory, buffer on disk, encrypt, and  dealing with attachments
in general are implementation details of the  JAX-WS framework and not covered by the JAX-WS
specification.

 OpenCMIS supports streaming if the Sun JAX-WS RI is used. The  WSConverter checks for each
stream if "read once" is available and use  it, if it is available.
 But it is really easy to break. For example, putting a SOAP Handler in  front of the service
can force the JAX-WS implementation to read the  whole content into memory.

 OpenCMIS does not use mimepull directly. It's a dependency of the Sun  JAX-WS RI. We can't
influence how the Sun JAX-WS RI uses it and when it  uses the feature you have mentioned.

 The only way to get full control is to develop our own Web Services  stack and I doubt that
we will do that.


 - Florian


> Hi,
>
> With Webservice-binding uploaded content gets loaded completely on
> the server (either in memory or on disk, depending on the size, as
> specified in the StreamingAttachment's memoryThreshold).
> This issue has been discussed before in regards to encryption and
> configurability of the threshold.
> But I wonder why content must be buffered at all.
>
> According to https://mimepull.java.net, streaming should be possible 
> if
> - "The parts are accessed in the same order as they appear in the 
> stream"
> - "The parts are accessed only once."
> I believe the read-once condition is complied with by OpenCMIS
> (org.apache.chemistry.opencmis.commons.impl.WSConverter).
>
> So why is streaming not possible with OpenCMIS?
>
> Thanks for a short explanation (or even a solution ;-)
> Uwe

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