In a REST application, i need to publish a message in this flow:
RESTApi -> ComputeNode -> Publication -> ...
Can I publish without using an MQInput / Output? How can i do it?
Yes, you should be able to set up the Properties tree to allow the Publication node to work without receiving the input message on MQ Input. MQ Output is not needed.
From the IIB knowledge center:
The message being published must:
Be a Publish command message
Be a Delete Publication command message, or
Have at least one topic present in the standard properties of the message.
The 3rd option seems like the one you need.