SQLAlchemy-Api-Handler 0.14.2

Adds SQLAlchemy support to your Flask application for handle apis.

sqlalchemy-api-handler

SQLAlchemy-Api-Handler is an extension that adds support for handling apis with sqlalchemy. It helps to handle models with :

• humanized ids once it is jsonified,
• throwing api errors for some casting of value during the save time,
• dictification of the model objects into jsonified ones.
• It also gives an activate method to help you better handle offline operational transforms, based on the PostgreSQL-Audit Activity model.

Installing

Install and update using pip:

  $ pip install -U SQLAlchemy-Api-Handler

A Simple Example

Suppose a request POST /users {'email': '[e-mail]', name: 'Marx Foo'} :

    from flask import Flask, jsonify, request
    from sqlalchemy_api_handler import ApiHandler

    app = Flask(__name__)
    app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///example.sqlite'
    db = SQLAlchemy(app)
    ApiHandler.set_db(db)

    class User(ApiHandler, db.Model):
        email = db.Column(db.String, unique=True, nullable=False)
        name = db.Column(db.String, unique=True, nullable=False)

    @app.route('/users', methods=['POST'])
    def post_user():
      user = User(**request.form)
      ApiHandler.save(user)
      return jsonify(as_dict(user))

The success result will have stored a user object at, let's say id = 32, and so will fetch an object at humanized id = humanize(32), ie

  {'id': 'EA', 'email': '[e-mail]', name: 'Marx Foo'}

Playing with nesting data

Suppose a request GET /offers

    from flask import Flask, jsonify, request
    from sqlalchemy.orm import relationship
    from sqlalchemy_api_handler import ApiHandler

    app = Flask(__name__)
    app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///example.sqlite'
    db = SQLAlchemy(app)
    ApiHandler.set_db(db)

    class Venue(ApiHandler, db.Model):
        address = db.Column(db.String, unique=True, nullable=False)
        name = db.Column(db.String, unique=True, nullable=False)

    class Offer(ApiHandler, db.Model):
        name = db.Column(db.String, unique=True, nullable=False)
        venueId = db.Column(db.BigInteger,
                     db.ForeignKey('venue.id'),
                     nullable=False,
                     index=True)
        venue = relationship('Venue',
                             foreign_keys=[venueId],
                             backref='offers')

    class Stock(ApiHandler, db.Model):
        available = db.Column(db.Integer, nullable=False)
        offerId = db.Column(db.BigInteger,
                         db.ForeignKey('offer.id'),
                         index=True,
                         nullable=False)
        offer = relationship('Offer',
                             foreign_keys=[offerId],
                             backref='stocks')

    venue = Venue(address='Somewhere I belong', name='MyVenue')
    offer = Offer(name='MyOffer')
    stock = Stock(available=10)
    stock.offer = offer
    offer.venue = venue
    ApiHandler.save(stock)

    offer_includes = [
      'stocks',
      {
        'key': 'venue',
        'includes': [
          '-address'
        ]
      }
    ]

    @app.route('/offers', methods=['GET'])
    def get_offers():
      offers = Offer.query.all()
      return jsonify(as_dict(offers, includes=offer_includes))

The success will return

  [
    {
      'id': 'AE',
      'name': 'MyOffer',
      'stocks': [
        {
          'available': 10,
          'id': 'AE'
        }
      ],
      'venue': {
        'name': 'MyVenue'
      }
    }
  ]

Activity

If you need to manage operation transforms of your entities (typically with a collaborative app working offline) :

    from flask import Flask, jsonify, request
    from sqlalchemy.orm import relationship
    from sqlalchemy_api_handler import ApiHandler
    from sqlalchemy_api_handler.mixins import ActivityMixin, \
                                              HasActivitiesMixin

    app = Flask(__name__)
    app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///example.sqlite'
    db = SQLAlchemy(app)
    ApiHandler.set_db(db)

    versioning_manager.init(db.Model)
    class Activity(ActivityMixin,
                   ApiHandler,
                   versioning_manager.activity_cls):
        __table_args__ = {'extend_existing': True}

        id = versioning_manager.activity_cls.id
    ApiHandler.set_activity(Activity)

    class Venue(ApiHandler,
                db.Model,
                HasActivitiesMixin):
        address = db.Column(db.String, unique=True, nullable=False)
        name = db.Column(db.String, unique=True, nullable=False)

    @app.route('/__activities__', methods=['POST'])
    def create_activities():
        activities = [Activity(**a) for a in request.json]
        ApiHandler.activate(*activities)
        return jsonify([as_dict(activity) for activity in activities]), 201

The request POST /activities helps you to sync your backend with the last state of pushed activities. For example, if the data posted is :

[
  {
    "dateCreated": "2020-08-05T08:34:06.415000Z" ,
    "entityIdentifier": "4039fb61-f085-43c4-a2ed-e5e97c5dcebc",
    "modelName": "Venue",
    "patch": { "address": "22 rue de la Loire", "name": "MyVenue" }
  },
  {
    "dateCreated": "2020-08-06T09:34:06.415000Z" ,
    "entityIdentifier": "4039fb61-f085-43c4-a2ed-e5e97c5dcebc",
    "modelName": "Venue",
    "patch": { "name": "MyVenueChanged" }
  }
]

It will then end to create a venue instance:

venue = Venue.query.filter_by(name='MyVenueChanged').first()
print(as_dict(venue, includes=['__activities__']))

{
  '__activities__': [
    {
      'dateCreated': '2020-08-05T08:34:06.415000Z',
      'entityIdentifier': '4039fb61-f085-43c4-a2ed-e5e97c5dcebc',
      'id': 'BA',
      'modelName': 'Venue',
      'patch': {
        'address': '22 rue de la Loire',
        'name': 'MyVenue'
      },
      'verb': 'insert'
    },
    {
      'dateCreated': '2020-08-06T09:34:06.415000Z',
      'entityIdentifier': '4039fb61-f085-43c4-a2ed-e5e97c5dcebc',
      'id': 'BF',
      'modelName': 'Venue',
      'patch': {
        'name': 'MyVenueChanged'
      },
      'verb': 'update'
    }
  ],
  'activityIdentifier': '2020-08-05T08:34:06.415000Z',
  'address': "22 rue de la Loire",
  'id': 'AE',
  'name': 'MyVenueChanged'
}

Celery

Sometimes it's hard to track celery tasks from the celery cli itself. And you may not want use flower when you have one exposed port by application, like in scalingo classic services. Therefore, ApiHandler can also synchronise the tasks to be stored in your postgres db, then you can build your Tasks Manager Dashboard front easy as you want, querying from classic postgres api routes. See how the example is build in the api folder.

Links

• Releases: https://pypi.org/project/SQLAlchemy-Api-Handler/

• Code: https://github.com/betagouv/sqlalchemy-api-handler

• Issue tracker: https://github.com/betagouv/sqlalchemy-api-handler/issues

• Flask: https://betagouvprojects.com/p/flask/

• SQLAlchemy: https://www.sqlalchemy.org

• pip: https://pip.pypa.io/en/stable/quickstart/

Deploy

First, make sure that the deploy environment is started:

  ./sqlaah start

In a second tab, then:

2. Change the version into sqlalchemy_api_handler/init.py

3. Pre publish:

  ./sqlaah prepublish

4. Publish:

  ./sqlaah publish