title: How to process data before storing to database in python eve
body: <p>I'm currently learning python eve framework and mongoDB database for restful API development. In eve, basic CRUD operations are done only by defining the schema in <code>settings.py</code> file. Client can send GET/POST methods and data is automatically stored into mongoDB according to the predefined schema.</p>
  
  <p>What if I want to preprocess my data before inserting it into mongoDB (e.g.: Client only sends product quantity and price, then the server calculates the total amount and stores product, price and amount to the database). And what if I want to process my data before respond to client. Should we use flask controller methods(like this <a href="https://stackoverflow.com/questions/21700113/eve-define-custom-flask-controllers">EVE - define custom flask controllers</a>) and manually store the data to database?</p>