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From Uwe Geisert <ugeis...@opentext.com>
Subject RE: Streaming capability with WS binding
Date Mon, 04 Jan 2016 15:14:53 GMT
Hi,

Happy New Year everybody!

Quite a while ago we found that in OpenCMIS 0.10.0 the parseEagerly=true in StreamingAttachment
caused content to be buffered in tomcat's temp directory (or in memory). See below.

This was fixed in OpenCMIS 0.11.0.

There is a client-side counterpart in chemistry-opencmis-client-bindings/src/main/java/org/apache/chemistry/opencmis/client/bindings/spi/webservices/SunRIPortProvider.java,
line 65:  a StreamingAttachmentFeature is created with parseEagerly=true. This causes MIME*.tmp
files to be created in %TEMP% for every sufficiently big document that is downloaded.

Would that be something that could be changed or made customizable in a future OpenCMIS version?

Thanks
Uwe

-----Original Message-----
From: Florian Müller [mailto:fmui@apache.org] 
Sent: Dienstag, 19. November 2013 12:22
To: Uwe Geisert
Cc: dev@chemistry.apache.org
Subject: RE: Streaming capability with WS binding

 Hi Uwe,

 The current code base (in trunk) does not do eager parsing.


 - Florian


> 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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