Python Web Practice Assessment

In this assessment, you will create a simple, data-driven Web application using Python. The tests are provided for you in this project; however, there is no Pipfile because part of this assessment is for you to initialize and use your own virtual environment using Pipenv.

During this assessment, you can access the following resources:

• The Alembic documentation
• The Flask-Migrate documentation
• The Flask-SQLAlchemy documentation
• The Flask-WTF documentation
• The SQLAlchemy documentation
• The WTForms documentation
• The Python documentation

Getting started

Your application should use a database.

• Create a database user named “pyweb_practice_user” with password “pyweb”
• Create a database named “pyweb_practice_db” with owner “pyweb_practice_user”
• Determine your PostgreSQL database connection URI

Use Pipenv to install the following dependencies.

• pytest
• pycodestyle
• pylint
• rope
• flask
• flask-sqlalchemy
• alembic
• flask-migrate
• python-dotenv
• psycopg2-binary
• sqlalchemy
• wtforms
• flask-wtf

Once you have those installed, activate your virtual environment.

The tests will expect you to store your application’s code in an app/ directory. Inside the app/ directory, you will need to

• Create a __init__.py file which will contain your Flask app declaration
• Create a forms.py file which will contain your form classes
• Create a models.py file which will contain your Flask-SQLAlchemy model classes.
• Create a config.py file which will contain your configuration object

NOTE: If you are going to view this application in the browser while you develop it, you will need to set a SECRET_KEY in your configuration. The unit tests do not require it to be set. There is a reminder, later, to add it when you’ll need it.

The requirements

For each of the following routes, you need to implement the requirements. These requirements are what the tests test.

App location

In the app/__init__.py file, create your Flask application. You must name the variable that holds the Flask application app.

You can define the routes wherever you’d like: in their own Blueprints or in the app/__init__.py file. Think of what file you need to import the app from the app directory.

GET “/”

The response from this HTTP request must be of type “text/html” (Flask sets this for you when you render a template) and contain the following HTML:

<h1>Practice Assessment</h1>

GET “/simple-form”

You must create a form class using Flask-WTF and WTForms. You must define this in the app.forms module. The form class must be named SimpleForm. It must define a form with the following specifications.

NOTE: The bio field is a TEXTAREA!!!

Create a route to handle GET /simple-form. In it use the form class you just defined and render a template containing the form HTML.

The response from this HTTP request must be of type “text/html” (Flask sets this for you when you render a template) and contain the form fields described above. The method of the form should be “post” and “/simple-form”. It should look exactly like this.

<form method="post" action="/simple-form">

NOTE: If you are going to view this in the browser, then you need to do things:

• Don’t forget to put the {{ form.csrf_token }} value in your form. (The form variable, there, is whatever you name the form parameter for the template.)
• Go ahead and create a class named Configuration in app.config. Add a SECRET_KEY value to it. Get that configuration into your application by following the instructions in the next section.

POST “/simple-form”

In the app.config module, create a class named Configuration. In there, create an attribute named SQLALCHEMY_DATABASE_URI and set it to the value of the proper PostgreSQL URL from the database information in the Getting started section. Add SQLALCHEMY_DATABASE_URI and SECRET_KEY to your .env file. Import your environment variables into app.config.py (We trust that you know how to use os.environ.get)

Notes: - If you are going to view this in the browser, add a SECRET_KEY attribute to the Configuration object, as well, and set it to anything. - SQLAlchemy will issue a warnings about SQLALCHEMY_TRACK_MODIFICATIONS. These will not effect your tests passing, and can be ignored. Alternatively you may set it’s value to False in your configuration object to address the warnings.

Import the Configuration class into the app/__init__.py file and use it to configure your Flask application.

Create a mapping class (model) in the app.models module named SimplePerson. It must use the table name “simple_people”. It must have the following mappings on it.

Remember that you will need to construct a db object by calling the SQLAlchemy constructor. In order to avoid circular dependencies (caused by importing from app) import db into your app/__init__.py and call init_app on it.

Note: The assessment can cover INTEGER, VARCHAR, BOOLEAN, and TEXT types.

Create a migration for this and upgrade your database.

• Create a separate route to handle POST /simple-form.
• It should take the data from the posted form page (name, age, bio) and use the SimpleForm validate it
• If the form validates, it should
  • use the SimplePerson to insert it into the database using the SimplePerson
  • redirect to “/”.
• If the form does not validate, it should show a message that reads “Bad Data” (the content type can be anything, including plain text).

GET “/simple-form-data”

Create a route to handle GET /simple-form-data. In that route, have it query all of the records from using the SimplePerson for where the name begins with “M”. Loop over those records in your view and render them using the following template.

<-- Your for loop, here -->
<div>{{ person.name }}</div>
<div>{{ person.age }}</div>
<div>{{ person.bio }}</div>
{% endfor %}

The tests

The tests are grouped into two categories: simple and data-driven. The “simple” tests do not require a database. The “data-driven” tests require you to store data in a database by creating proper models. The model classes will be inspected.

The “simple” tests

These tests will check that the responses have values in the HTML and in your SimpleForm class.

The “database” tests

These tests will check your Configuration class, that those values are put into your Flask application’s config object, the model exist in your app.models module, and that your routes handle and show data created in your application.