I'm currently trying to create an API which will depending of the action create/modify/fetch data from Reuters but I didn't find a proper API/library which does that. Is it possible ? If it's possible, do you have an example ?
You can create and then edit or delete those RICS on your local TREP for internal consumption within your organisation.
The ADH component of TREP allows you to define a Cached service in which you can create records etc. I have an article on this website which talks about a specific use case scenario using this ADH cache facility - hopefully you will find some of the information relevant.
And yes you can use any of our realtime APIs to create records in the cache - including the Websocket API. The article above is based on EMA - however, the Post Msg functionality I refer to can be implemented using Websocket - see this tutorial on how to Post messages using Websocket API.
You will need to liaise with your Market Data team in order for them to define the cache service on your ADH.
If you do not have ATS product,
On the consumer part, you can use OMM Consumer from EMA (part of ESDK) to consumer realtime data from ELEKTRON_DD datafeed.
On Provider part:
You can use OMMProvider from EMA (part of ESDK).
OMMProvider acts as a datafeed.
You can use OMMNIProvider (OMM Non-Interactive Provider) to publish data to ADH.
If you have ATS product, you can use WebSocket API to consumer and post a message to TREP. (So Python or C# can be used)
I think it is better to contact your CSM (or Technical Account Manager) so they can have a discussion with you on your needs.