Flask restless
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This document provides an overview of Flask Restless, a library for building REST APIs with Flask and SQLAlchemy. It allows you to define models and their relationships, then expose them through API endpoints with minimal configuration. Flask Restless handles common tasks like pagination, filtering queries, and relationships automatically. It uses SQLAlchemy under the hood, so models can represent different database backends. The document includes code samples and discusses features like preprocessing requests, validation, and querying data through filters.
![Turning a Model into a API
# Create the DB
db.create_all()
# Create the Flask-Restless API manager.
manager = APIManager(app, flask_sqlalchemy_db=db)
# Create the API endpoints from the DB Models
# These will be available at /api/<tablename>
manager.create_api(Beer, methods=['GET', 'POST', 'PUT',
'DELETE'])](https://image.slidesharecdn.com/flaskrestless-160511231702/85/Flask-restless-8-320.jpg)
![Excluding Columns
You can use exclude_columns or include_columns
to hide columns in the response
manager.create_api(Beer, methods=['GET', 'POST', 'PUT',
'DELETE'], exclude_columns=['reviews', 'type'])](https://image.slidesharecdn.com/flaskrestless-160511231702/85/Flask-restless-14-320.jpg)
![Processors
# Augments the request with the current db DATETIMESTAMP
# When submitted
def add_current_date(**kw):
kw['data']['date'] = 'CURRENT_TIMESTAMP'
return kw
# Create the API endpoints from the DB Models
# These will be available at /api/<tablename>
manager.create_api(
Review,
methods=['GET', 'POST', 'PUT', 'DELETE'],
preprocessors = {
'POST': [add_current_date],
'PUT_SINGLE': [add_current_date]
}
)](https://image.slidesharecdn.com/flaskrestless-160511231702/85/Flask-restless-18-320.jpg)
![Server side Pagination
Natively uses server side pagination (default is 10
results per page)
<host>/api/<resource>?page=2 Give you page 2
Set the results_per_page attribute when creating
your api to over-ride
manager.create_api(Reviewer, methods=['GET', 'POST',
'PUT', 'DELETE'], results_per_page=2)](https://image.slidesharecdn.com/flaskrestless-160511231702/85/Flask-restless-25-320.jpg)
![Querying Data
Support query params on GETS
Uses Query Filters
<host>/api/<resource>/?q={“filter”:[…filters…]}](https://image.slidesharecdn.com/flaskrestless-160511231702/85/Flask-restless-27-320.jpg)
![Examples
Get all the Hipsters
GET localhost:5000/api/reviewer?q={"filters":
[{"name":"name","op": "ilike", "val":"Hipster%"}]}
Reviews with more than 3 stars
GET localhost:5000/api/review?q={"filters":
[{"name":"stars","op": "gt", "val":3}]}
All reviews made by Hipster Jane
GET localhost:5000/api/review?q={"filters":
[{"name":"author","op":"has","val":{"name":"name",
"op":"eq", "val":"Hipster Jane”}}]}](https://image.slidesharecdn.com/flaskrestless-160511231702/85/Flask-restless-31-320.jpg)
Flask restless
- 1. FLASK RESTLESS FAST AND EASY REST API’S
- 3. What is Flask Restless Library built around flask Model driven Define your models Define their relationships Expose your models Specify what to expose them on (GET, POST, PUT, DELETE
- 4. What is Flask Restless Uses SQLAlchemy Supports SQLite, Postgresql, MySQL, Oracle and many more Built in query language (FOR FREE!)
- 5. Models What is a model? Comes from SQLAlchemy or Flask-SQLAlchemy Used to represent objects which will become records in a database
- 6. Flask-SQLAlchemy Abstracts away a lot of unnecessary SQLAlchemy config and makes your life easier. Read more here
- 7. Defining a Model # Define the models class Beer(db.Model): id = db.Column(db.Integer, primary_key=True) name = db.Column(db.Unicode, unique=True) Will execute: CREATE TABLE beer ( id INTEGER NOT NULL, name VARCHAR, PRIMARY KEY (id), UNIQUE (name), )
- 8. Turning a Model into a API # Create the DB db.create_all() # Create the Flask-Restless API manager. manager = APIManager(app, flask_sqlalchemy_db=db) # Create the API endpoints from the DB Models # These will be available at /api/<tablename> manager.create_api(Beer, methods=['GET', 'POST', 'PUT', 'DELETE'])
- 9. DEMO STEP/1
- 10. Relationships
- 11. Creating a one to many Relationship Relationship always goes on the ‘one’ side # Define the models class Beer(db.Model): id = db.Column(db.Integer, primary_key=True) name = db.Column(db.Unicode, unique=True) # Create a foreign key type_id = db.Column(db.Integer, db.ForeignKey(‘type.id’)) class Type(db.Model): id = db.Column(db.Integer, primary_key=True) name = db.Column(db.Unicode, unique=True) # Create a relationship beers = db.relationship('Beer', backref=db.backref('type'), lazy=‘dynamic')
- 12. DEMO STEP/2
- 14. Excluding Columns You can use exclude_columns or include_columns to hide columns in the response manager.create_api(Beer, methods=['GET', 'POST', 'PUT', 'DELETE'], exclude_columns=['reviews', 'type'])
- 15. DEMO STEP/3
- 16. Pre and Post Processing
- 17. Consider On a POST or PUT for a review you want to add the date that the review was created Do you? Do this client side (What time zone? What format) Do this server side
- 18. Processors # Augments the request with the current db DATETIMESTAMP # When submitted def add_current_date(**kw): kw['data']['date'] = 'CURRENT_TIMESTAMP' return kw # Create the API endpoints from the DB Models # These will be available at /api/<tablename> manager.create_api( Review, methods=['GET', 'POST', 'PUT', 'DELETE'], preprocessors = { 'POST': [add_current_date], 'PUT_SINGLE': [add_current_date] } )
- 19. Processors Preprocessors -> before the requests is processed Postprocessors -> before the response is returned
- 20. DEMO STEP/4
- 21. Validation
- 22. Validation Not performed by Flask-Restless Roll your own or use a combination of the SQLAlchemy validate decorator and flasks abort
- 23. Validation from flask import Flask, abort from sqlalchemy.orm import validates class Review(db.Model): id = db.Column(db.Integer, primary_key=True) date = db.Column(db.DateTime) stars = db.Column(db.Integer) comment = db.Column(db.Unicode) beer_id = db.Column(db.Integer, db.ForeignKey('beer.id')) author_id = db.Column(db.Integer, db.ForeignKey('reviewer.id')) @validates('stars') def validate_name(self, key, stars): if stars >= 1 and stars <=5: return stars else: return abort(400, description='A review must have a star rating of between 1 and 5')
- 24. Pagination
- 25. Server side Pagination Natively uses server side pagination (default is 10 results per page) <host>/api/<resource>?page=2 Give you page 2 Set the results_per_page attribute when creating your api to over-ride manager.create_api(Reviewer, methods=['GET', 'POST', 'PUT', 'DELETE'], results_per_page=2)
- 26. Querying data NULL is the Chuck Norris of the database. Nothing can be compared to it. - Unknown
- 27. Querying Data Support query params on GETS Uses Query Filters <host>/api/<resource>/?q={“filter”:[…filters…]}
- 28. Query Filters Lists of {“name”: name, “op”: op, “val”: val} {“name”: name, “op”: op, “field”: field} name The field to use op The operator to use val The Value to use field The field to compare name to
- 29. Valid Operators equal ==, eq, equals, equals_to not equal !=, neq, does_not_equal, not_equal_to comparison >, gt, <, lt, >=, ge, gte, geq, <=, le, lte, leq membership in, not_in null check is_null, is_not_null like like has has any any
- 30. Querying Data Extremely feature rich Order by Group By Single result expected READ THE DOCS
- 31. Examples Get all the Hipsters GET localhost:5000/api/reviewer?q={"filters": [{"name":"name","op": "ilike", "val":"Hipster%"}]} Reviews with more than 3 stars GET localhost:5000/api/review?q={"filters": [{"name":"stars","op": "gt", "val":3}]} All reviews made by Hipster Jane GET localhost:5000/api/review?q={"filters": [{"name":"author","op":"has","val":{"name":"name", "op":"eq", "val":"Hipster Jane”}}]}
- 32. Examples You can also use relationships in a GET All reviews made by Hipster Jane(id=2) GET localhost:5000/api/reviewer/2/ reviews
- 33. Further Reading You can use SQLAlchemy migrate to migrate you DB revisions Read all about it (and lots more) here
- 34. QUESTIONS?