Modifying a Flask-Restless result array

Question

I have something like this:

{
  "id": 1, 
  "username": "plasmy",
  "userdetails": [
    {
      "detail": "A Name", 
      "detail_name": "Full Name", 
      "id": 1, 
      "user_id": 1
    }, 
    {
      "detail": "an@email.com", 
      "detail_name": "Email", 
      "id": 2, 
      "user_id": 1
    }, 
    {
      "detail": "An Address", 
      "detail_name": "Address", 
      "id": 3, 
      "user_id": 1
    }, 
    {
      "detail": "999-999-9999", 
      "detail_name": "Phone Number", 
      "id": 4, 
      "user_id": 1
    }
  ]
}

This comes as a result from using Flask_Restless and SQLAlchemy. There is a table for users and a table for userdetails, which are put in the userdetails part of that JSON. What I want to do is, find a way in which the data can look like this:

{
  "id": 1, 
  "username": "plasmy",
  "userdetails": {
      "Full Name": "A Name",
      "Email": "an@email.com",
      "Address": "An Address",
      "Phone Number": "A Phone Number"
    }
}

See how I removed the ids and I used the field "detail_name" as the key and "detail" as value. I tried using preprocessors but they didn't work or maybe I'm using them wrong. I put the preprocessor in the "child" table.

This is what I tried doing (but didn't work):

def detail_sort(results):
    return {'user_details': results['userdetails']}


manager.create_api(User, methods=['GET', 'POST'])
manager.create_api(UserDetails, methods=['GET', 'POST'],
                   preprocessors={
                       'GET_COLLECTION': [detail_sort]
                   })

I tried GET_COLLECTION, GET_SINGLE and GET_MANY. Any help on this will be greatly appreciated.

UPDATE: Here is the new code I tried based on the answer

from flask import Blueprint
from medinv import manager
from medinv.User.models import User, UserDetails

blueprint = Blueprint('blueprint', __name__)


@blueprint.route('/')
@blueprint.route('/home')
def home():
    return "Welcome."


def detail_sort(results):
    print(results)
    results['userdetails'] = {item['detail_name']: item['detail'] for item in results['userdetails']}
    return results['userdetails']


manager.create_api(User, methods=['GET', 'POST'])
manager.create_api(UserDetails, methods=['GET', 'POST'],
                   postprocessors={
                       'GET_COLLECTION': [detail_sort]
                   })

Answer 1

I think you need to use postproccessors since you need to modify the json response before sending it back to the client.

OK, I reproduced your problem. Now it's working. Here is my code:

import flask
import flask_sqlalchemy
import flask_restless

# Create the Flask application and the Flask-SQLAlchemy object.
app = flask.Flask(__name__)
app.config['DEBUG'] = True
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/test.db'
db = flask_sqlalchemy.SQLAlchemy(app)


# Create your Flask-SQLALchemy models as usual but with the following
# restriction: they must have an __init__ method that accepts keyword
# arguments for all columns (the constructor in
# flask_sqlalchemy.SQLAlchemy.Model supplies such a method, so you
# don't need to declare a new one).

class User(db.Model):

    __tablename__ = 'user'

    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String)
    userdetails = db.relationship('UserDetails', backref='User', lazy='dynamic')


class UserDetails(db.Model):

    __tablename__ = 'user_details'

    id = db.Column(db.Integer, primary_key=True)
    detail = db.Column(db.String)
    detail_name = db.Column(db.String)
    user_id = db.Column(db.Integer, db.ForeignKey("user.id"), nullable=False)

# Create the database tables.
db.create_all()

# Create the Flask-Restless API manager.
manager = flask_restless.APIManager(app, flask_sqlalchemy_db=db)

user = User(username='plasmy')
userdetail_0 = UserDetails(detail='A name', detail_name='Full Name' )
userdetail_1 = UserDetails(detail='an@email.com', detail_name='Email')
userdetail_2 = UserDetails(detail='An Address', detail_name='Address')
userdetail_3 = UserDetails(detail='999-999-9999', detail_name='Phone Number')


user.userdetails.append(userdetail_0)
user.userdetails.append(userdetail_1)
user.userdetails.append(userdetail_2)
user.userdetails.append(userdetail_3)

db.session.add(user)
db.session.commit()

print('USER CREATED')

def detail_sort(result, **kw):
    print('detail_sort called')
    print(result)

    for entry in result['objects']:
        entry['userdetails'] = {item['detail_name']: item['detail'] for item in
                                entry['userdetails']}
    print('MODIFIED JSON: ', result)

# Create API endpoints, which will be available at /api/<tablename> by
# default. Allowed HTTP methods can be specified as well.
# manager.create_api(Person, methods=['GET', 'POST', 'DELETE'])
# manager.create_api(Article, methods=['GET'])

manager.create_api(User, methods=['GET', 'POST', 'DELETE'],
                   postprocessors={
                       'GET_MANY': [detail_sort]
                   })
manager.create_api(UserDetails, methods=['GET'], )

# start the flask loop
app.run(use_reloader=False)

Note that you need to use GET_MANY and look how detail_sort is implemented.

Without using postprocessor the response is like this:

{
  "num_results": 1, 
  "objects": [
    {
      "id": 1, 
      "userdetails": [
        {
          "detail": "A name", 
          "detail_name": "Full Name", 
          "id": 1, 
          "user_id": 1
        }, 
        {
          "detail": "an@email.com", 
          "detail_name": "Email", 
          "id": 2, 
          "user_id": 1
        }, 
        {
          "detail": "An Address", 
          "detail_name": "Address", 
          "id": 3, 
          "user_id": 1
        }, 
        {
          "detail": "999-999-9999", 
          "detail_name": "Phone Number", 
          "id": 4, 
          "user_id": 1
        }
      ], 
      "username": "plasmy"
    }
  ], 
  "page": 1, 
  "total_pages": 1
}

With postprocessor the response looks like this:

{
  "num_results": 1, 
  "objects": [
    {
      "id": 1, 
      "userdetails": {
        "Address": "An Address", 
        "Email": "an@email.com", 
        "Full Name": "A name", 
        "Phone Number": "999-999-9999"
      }, 
      "username": "plasmy"
    }
  ], 
  "page": 1, 
  "total_pages": 1
}

Hope this helps.