Is there a REST server with Pub/Sub subscription and pre, post post processing?

Question

MySQL

I'm looking for an analogue of Parse.com, with the following features:
1. Subscribe on the client to change Pub/Sub data (preferably websockets). Sending not all messages (setting). Life timeout.
2. The ability to pre-process incoming data, and using other data (for example, a data structure has arrived, it must be converted to another before saving).
3. Relational database for the main storage (Mysql, PG).
4. Ideally, Open Source, but BAS is also possible and there is something paid on my server.
5. The number of records up to 30 per second, up to 1 million. in a day.