Using a dictionary template for consistent response structure from an API

Question

I am making a simple API for news items using Python and the Bottle framework.

I return a Python dictionary from my endpoints as Bottle converts this to JSON automatically in the response to the client.

I wanted to ensure a consistent structure to the responses, so I have declared a template dictionary. The code for each endpoint makes a deep copy of this then modifies the relevant data before returning it.

import bottle
from bottle import route
from copy import deepcopy as deepcopy
# Dictionary for response template
response_dict = {
"status" : "ok",
"code" : 0,
"error" : False,
"message" : "",
"result" : {}
}
# Example route
@route('/example')
def example():
 return_dict = deepcopy(response_dict)
 return_dict["message"] = "Success"
 return_dict["result"] = {
 "title" : "Test Title",
 "body" : "<p>Lorem ipsum dolor sit amet...</p>"
 }
 return return_dict

I would like to know if there is a better way to use a template for a JSON response and whether the structure of my dictionary is appropriate.

Answer 1

There is no need to use deepcopy here. Just have a function that returns a new object when you need it. And while you're at it, just make the message and the result parameters of that function. Or even all of them:

def json_response(message, result, status="ok", code=0, error=False):
 return {
 "status" : status,
 "code" : code,
 "error" : error,
 "message" : message,
 "result" : result
 }
@route('/example')
def example():
 result = {
 "title" : "Test Title",
 "body" : "<p>Lorem ipsum dolor sit amet...</p>"
 }
 return json_response("Success", result)

Having all as parameters, but with default values, allows you to do this in the future:

json_response("Failure", None, status="fail", code=404, error=True)

In the end it depends on how often you need to use this template whether or not this is better than just directly returning the dictionary explicitly:

@route('/example')
def example():
 return {
 "status" : "ok",
 "code" : 0,
 "error" : False,
 "message" : "Success",
 "result" : {
 "title" : "Test Title",
 "body" : "<p>Lorem ipsum dolor sit amet...</p>"
 }
 }

• Chris: Thanks for this. I was fixated on using the dictionary and hadn’t thought about using a function. It seems much more straightforward.