Thursday, 2 July 2015

OSB & MTOM: When to use Include Binary Data by Reference or Value

As can be seen in my blogs of these days, I've been busy with implementing a service using MTOM in OSB. When enabling XOP/MTOM Support you'll have to choose between:
  • Include Binary Data by Reference
  • Include Binary Data by Value

I used the first because I want to process the content in another service on another WLS-Domain. However, in my first service catching the initial request I want to do an XSD validation. And although the rest of the message is valid, the Validate activity raises an exception with the message: 'Element not allowed: binary-content@ in element Bestandsdata....'.

Looking into this problem I came up with this section in the doc,  which states that you use 'Include Binary Data by Value' when you want to:
  • transfer your data to a service that does not support MTOM
  • validate your message
Now, what does this other option? OSB then parses the root of the Inbound MIME message in search for  xop:Include-tags. When found, it will Base64 encode the binary-content and replaces the tags with the Base64-string.

Now, although I want exactly that in the end, I don't want that at this point of the service. I want to transform my message, without the Base64-strings. And I want to encode the data only on my other domain.

So I just want to ignore messages that start with the 'Element not allowed: binary-content@...' messages. To do so I came up with the next expression:
fn:count($fault/ctx:details/con:ValidationFailureDetail/con:message[not(fn:starts-with(text(),'Element not allowed: binary-content@ in element Bestandsdata'))])>0 
Add an If-Then-Else activity to your Error Handler Stage with this expression. Add the following Namespace:
  • Prefix: con
  • Namespace:

If the expression evaluates to true, then you have in fact an invalid XML-message. In the else branch you can add a Resume to ignore the exception.

This expression might come in handy in other situations as well.

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