Payload with images processing

Question

Hello,
My problem may be pretty common but i cannot decide on most suitable approach. So i turned to this forum where i always find an answer.
I have to develop a flow, XML over JMS, to receive a message payload with number of images as base64Binary in specific elements e.g country, city, area
<Payload>
<country>
<element/>
<element/>
<Image>EQ==</Image> <!-- Optional -->
</country>
<City>
<element/>
<element/>
<CityImages><!-- Optional -->
<Image>EQ==</Image>
<Image>EQ==</Image>
</Image>EQ==</Image>
</CityImages>
<Area>
<element/>
<element/>
<Images> <!-- these images are must -->
<Image1>EQ==</AreaImage1>
<Image2>EQ==</AreaImage2>
</Images>
</Area
</Payload>
These images will be stored in a separate system before rest of the payload is forwarded to a different system.
The system where images needs to be stored expose a web service and will return a unique image reference number for each image we store. Created a XQuery which will wrap all images in collection of documents sent to local service. And second XQuery will go through that collection of document and create a request payload for the image processing service. Second XQuery also assign Id to each image as serial number (1, 2, 3...) in the order they are present in the collection when it processes collection of document. The request to image web service goes as one payload with multiple images e.g. <DataSource><Query><id>1</id><image>EQ==</image></Query><Query><id>1</id><image>EQ==</image></Query></DataSource> with unique id and image content.Response contains Id and image reference number e.g. <QueryResult><result><id>1</id><ref>AB1312</ref><></result><result><id>2</id><ref>AB1124</ref><></result></QueryResult>.
Images contents in original payload will then be replaced with the reference numbers returned from the images system.
Now the problems i have is:
1 - First Xquery which creates document collection goes through the payload and when it finds an image it create a document element but i am unable to generate unique ID, in xquery, for each image found in original payload. Second Xquery goes through document collection and uses 'at $count' in for loop as counter and assign that to Id attribute. Ideally unique id sould be generated in the flow or first xquery, instead of second xquery, some how and used as reference?
2 - I intend to correlate returned image reference number based on the sequence(assumption) in which image appear in the original payload instead of using any cross refence mechanism.
I seek guidance on my solution on how best to correlate image reference number with corresponding image in the original payload.
Many Thanks for help!
Sall0

Answer 1

You can use the fn-bea:uuid() xquery function to generate unique id's for each image in the first xquery.
For correlating the image ref no to the actual image in the payload , what you are following based on sequence looks ok, since there is no reference available for each image on the original payload, kind of using the image index within the original payload looks fine.