Re: [ebxml-msg] Implementing Compression in AS4

[Theo Kramer <theo@flame.co.za>]

Hi Pim

Thanks for the feedback/input - comments inline.

On 26 Sep 2011, at 11:23 AM, Pim van der Eijk wrote:

> 
> Hello Theo,
> 
> 1.  There are situations where the MIME type of a payload
> can be inferred,  say, from the values for Service/Action.
> For example, S1/A1 type messages always contain one payload
> and it's an XML document, S2/A2 type messages always have
> two payloads, the first of which is a PDF document and the
> second a JPEG image, etc. The MSH can just pass the metadata
> and pointers to payloads to the application.  For
> decompressed payloads that do not have the MIME type
> specificied as an attribute,  the MIME type is effectively
> unknown, but the business application may still know how to
> process the payload content. 

Not ideal imo. Our preference would be to have the eb:Property[@name='MimeType'] 
attribute as mandatory in the spec.

> 2.  Why would you want that?  Base64 encoding increases the
> message size, which the compression feature is intended to
> reduce.  AS4 is layered over HTTP, and HTTP allows binary
> attachments such as GZIP data.   My assumption is that
> compressed payloads, even XML payloads, should always go as
> separate MIME parts, not in the SOAP body (where Base64
> encoding would be required).  That assumption seems
> imexplicit in the AS4 specification. 

You are right - thanks. We have taken out the base64 encoding and tested as working.

> 3.  We should probably change this to something like:
> <eb:Property name="Compressed">true</eb:Property>
> Unfortunately that means a specification change.

Thanks - we have amended our system to conform to the above and works perfectly. 
I would recommend an amendment on this asap.

-- 
Regards
Theo