Override Python Eve Endpoint because of backend column changes? - eve

Question

How do I override an endpoint if I want to run some data transformations before it hit's the database. For e.g., let's say we had a people table, with a column name fname and we renamed it to first_name. But our users are making queries with fname. Is there a way of overriding the endpoint with a custom route for people so that I can transform the column name from fname to first_name or more complexly, run some python code before either calling SQLALchemy by myself or perhaps returning it back to the Eve framework to continue with calling the database?
E.g. using the QuickStart, I tried something like this but it didn't work:
from eve import Eve
from flask import jsonify
app = Eve()
#app.route('/people/<name>')
def custom_people_func(name):
return jsonify(name='Override', people_name=name)
if __name__ == '__main__':
app.run()
settings.py
people = {
# 'title' tag used in item links. Defaults to the resource title minus
# the final, plural 's' (works fine in most cases but not for 'people')
'item_title': 'person',
# by default the standard item entry point is defined as
# '/people/<ObjectId>'. We leave it untouched, and we also enable an
# additional read-only entry point. This way consumers can also perform
# GET requests at '/people/<lastname>'.
'additional_lookup': {
'url': 'regex("[\w]+")',
'field': 'lastname'
},
# We choose to override global cache-control directives for this resource.
'cache_control': 'max-age=10,must-revalidate',
'cache_expires': 10,
# most global settings can be overridden at resource level
'resource_methods': ['GET', 'POST'],
'schema': schema
}
DOMAIN = {'people': people}
When I do curl -i http://127.0.0.1:5000/people/obama, it won't call the method I defined but the default Eve routing.
Asking generally, how do we manage these kind of database changes, if possible, using Eve?

Answer 1

Have you looked into Event Hooks, specifically into database event hooks? They allow you to hook a callout function to your db events (insert, replace, delete, fetch.) Within your function you can, for example, change the incoming payload before it hits the database.
>>> def before_insert(resource_name, items):
... print('About to store items to "%s" ' % resource)
... # modify incoming items here
>>> app = Eve()
>>> app.on_insert += before_insert
>>> app.run()