Chapter 6. But I Wanna REST Mom, Now!

REST is an architectural style that has been gaining momentum these last few years due to its many features and architectural constraints such as cacheability, stateless behavior, and its interface requirement.

Tip

For a nice overview of REST architecture, refer to http://www.drdobbs.com/Web-development/restful-Web-services-a-tutorial/240169069 and http://en.wikipedia.org/wiki/Representational_state_transfer.

Our focus in this chapter will be on RESTful Web Services and APIs—that is, Web services and Web APIs following the REST architecture. Let's start at the beginning: what is a Web service?

A Web service is a Web application that can be consulted by your application as if it was an API, improving the user experience. If your RESTful Web service does not need to be called from a traditional UI interface, and may be used standalone, then what you have is a RESTful Web Service API, "RESTful API" for short, that works just like a regular API, but through...

Beyond GET

So far we've had a few cozy examples with Ajax and RESTful Web services but we have yet to record data in our database using a service. How about trying that now?

Recording to the database using Web services is not much different from what we have done in the previous chapter. We'll receive data from an Ajax request, we will check which HTTP method was used in order to decide what to do, then we'll validate the sent data and save everything if no error was found. In Chapter 4, Please Fill in This Form, Madam, we talked about CSRF protection and its importance. We'll keep validating our data against CSRF with our Web service. The trick is to add the CSRF token to the form data being submitted. See the attached code provided with the eBook for the example HTML.

This is how our view looks like with POST, PUT, and REMOVE method support:

@app.route("/articles/", methods=["GET", "POST"])
@app.route("/articles/<int:article_id>", methods=["GET", "PUT", "DELETE"])
def articles(article_id...

Flask-Restless

Flask-Restless is an extension capable of auto-generating a whole RESTful API for your SQLAlchemy models with support for GET, POST, PUT, and DELETE. Most Web services won't need more than that. Another advantage to using Flask-Restless is the chance to extend the auto-generated methods with authentication validation, custom behavior, and custom queries. This is a must-learn extension!

Let's see how our Web service would look with Flask-Restless. We'll also have to install a new library for this example:

pip install Flask-Restless

And then:

# coding:utf-8

from flask import Flask, url_for
from flask.ext.restless import APIManager
from flask.ext.sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SECRET_KEY'] = 'secret'
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/employees.sqlite'

db = SQLAlchemy(app)


class Article(db.Model):
    __tablename__ = 'articles'

    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(100), nullable...

Summary

In this chapter, we learned what REST is, its advantages, how to create Flask RESTful Web Services and APIs, and how to use Flask-RESTless to make the whole thing work well. We also had an overview on what jQuery is and how to use it to send Ajax requests to consult our services. These chapter examples were pretty intense. Try to code the examples yourself, to assimilate them better.

In the next chapter, we'll be talking about the one way in which you can assure software quality: tests! We'll learn how to test our Web applications in the many ways that they may be tested and how to integrate these tests into our very coding routines. See you there!